Research Article |
Sung Joon Song‡§, Sang-kyu Lee§, Mijin Kim|, Kai Horst George¶, Jong Seong Khim§
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Corresponding author: Kai Horst George ( kgeorge@senckenberg.de ) Corresponding author: Jong Seong Khim ( jskocean@snu.ac.kr ) Academic editor: Kay Van Damme
© 2023 Sung Joon Song, Sang-kyu Lee, Mijin Kim, Kai Horst George, Jong Seong Khim.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Song SJ, Lee S-k, Kim M, George KH, Khim JS (2023) Phylogenetic revision of Echinolaophonte Nicholls (Copepoda, Harpacticoida, Laophontidae T. Scott) including the establishment of two new genera and two new species. Zoosystematics and Evolution 99(1): 217-252. https://doi.org/10.3897/zse.99.90114
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Abstract
The record of a new species of Echinolaophonte Nicholls, 1941 (Copepoda, Harpacticoida, Laophontidae) from Jeju Island (Korea) formed the basis for a detailed and exhaustive phylogenetic revision of the genus. Comparison of all 15 species currently assigned to Echinolaophonte (including the new Korean species) revealed that its current composition cannot be maintained. The phylogenetic relationships within Echinolaophonte were elucidated through the analysis of 135 morphological characters and the inclusion of four outgroups. As a result, four species were removed from Echinolaophonte and placed in two new genera: Parechinolaophonte gen. nov. for E. tropica Ummerkutty, 1970 and Pseudechinolaophonte gen. nov. for E. minuta Cottarelli & Forniz, 1991, E. mordoganensis Kuru, Sönmez & Karaytug, 2019 and E. veniliae Cottarelli, Forniz & Bascherini, 1992. Echinolaophonte longantennata Apostolov, 1990 had to be excluded from the analysis, due to the fragmentary and imprecise description. Accordingly, the phylogenetic relationships of the ten species remaining in Echinolaophonte are clarified. The new Korean species is described as Echinolaophonte musa sp. nov. Furthermore, the subspecies E. armiger f. briani Lang, 1965 is elevated to species rank as E. briani Lang, 1965. A detailed phylogenetic discussion is provided and a key to the species of Echinolaophonte is given.
Key Words
crustacea, meiofauna, Pacific Ocean, systematics, taxonomy
Introduction
When describing E. armiger f. typica Lang, 1965 from the Mediterranean Sea and E. armiger f. briani Lang, 1965 from the Californian coast (U.S.A.),
While examining collections of laophontid species deposited at the School of Biological Sciences, Seoul National University, we found a new species of Echinolaophonte obtained from the subtidal soft bottoms of Jeju Island, Korea. Here, we fully describe and illustrate it as E. musa sp. nov. Our attempt to clear the systematic relationship of the new species within Echinolaophonte required a fundamental, exhaustive phylogenetic analysis of the genus that is presented herein. Moreover, we provide an amended identification key to the species of the genus.
Methods
The specimens were collected by SCUBA diving from subtidal sandy bottoms at a depth range of 20–30 m at Munseom islet, Jeju Island.
The material was sieved with a 38 mm mesh and fixed in 95% ethanol. Benthic harpacticoid copepods were sorted in the laboratory using a Leica M165C (Germany) stereomicroscope. Specimens were then embedded in glycerol and dissected. The slide preparations were sealed with transparent nail varnish. Species identification and drawings were prepared using a drawing tube on an Olympus BX53 (Tokyo, Japan) differential interference contrast microscope, equipped with Nomarski optics.
Confocal Laser Scanning Microscopy (CLSM) was used at the DZMB (Senckenberg am Meer Wilhelmshaven, Germany) to examine the individuals, applying the methods shown, for example, in
The underlying morphological comparison of the used characters was made, based on the respective original species (re-)descriptions.
The terminology used follows
Abbreviations used in the text
A1, antennule; A2, antenna; ae, aesthetasc; cphth, cephalothorax; CR, caudal ramus/rami; GDS, genital double somite; md, mandible; mx, maxilla; mxl, maxillula; mxp, maxilliped; P1–P6, first to sixth thoracopod; exp (enp)-1 (2, 3) to denote the proximal (middle, distal) segment of a ramus.
Scale bars are in micrometres (μm). The type specimens are deposited in the collection of The Natural Institute of Biological Resources (NIBR), Incheon, Korea and The National Marine Biodiversity Institute of Korea (MABIK), Seochun, Korea.
Results
Subclass Copepoda Milne Edwards, 1840
Order Harpacticoida Sars, 1903
Family Laophontidae T. Scott, 1905
Echinolaophonte
Generic diagnosis
(modified from
Laophontidae T. Scott, 1905. Body elongate, cylindrical, podoplean boundary between pro- and urosome inconspicuous. Sexual dimorphism in A1, P3 (in the brevispinosa—oshoroensis clade only; not yet confirmed for E. gladiator), P4 (part.), P5, P6 and urosome segmentation (female with GDS due to fusion of last (P6-bearing, genital) thoracic somite with first abdominal somite). Cphth about 1/3 of total body length, with some sensilla laterally and dorsally; with strong, acute dorsal spur on posterior margin. Rostrum fused to cphth, laterally constricted, of different shape (dome, truncate, notch etc). Body somites, except preanal and telson, dorsally with cuticular processes of variable lengths. Preanal somite with highly variable pseudoperculum consisting of several, often digitate or squarrose processes (sometimes partly fused together). CR longer than broad, varying in length between species, with 7 setae. Female A1 slender, 6-segmented; male A1 sexually dimorphic, 8-segmented, subchirocer. A2 with 1-segmented exopod bearing 4 setae; allobasis with 1 or lacking abexopodal seta; endopod 1-segmented, subdistally with 2 spines and 1 slender additional seta, apically with 6 setae (2–3 geniculate)/spines. Mxp with elongated syncoxa and basis, prehensile, apical claw as long as basis. P1 prehensile, with extremely elongated coxa and basis, the latter reaching the length of enp-1. Exopod small, 2-segmented; endopod 2-segmented, enp-1 extremely elongated, enp-2 very small, with 1 strong claw and 1 tiny seta apically; P2–P4 with 3-segmented exopods, female with 2-segmented endopods; if sexually dimorphic, male P3 endopod 3-segmented, with strong apophysis on outer apical edge; those males lacking sexual dimorphism on P3 with 2-segmented endopod, resembling that of the female. Exopods of male P3 and P4 with or without sexual dimorphism. P5 of female with baseoendopod bearing 4 setae and with small distinct exopod carrying 3 setae. Male P5 smaller than in female, baseoendopod completely reduced; exopod distinct and small, with 3 setae.
Type species
Echinolaophonte horrida (Norman, 1876) (= Cleta horrida Norman, 1876; Laophonte horrida (Brady, 1880); Onychocamptus horridus (Lang, 1948)).
Additional species
E. armiger (Gurney, 1927) (= Laophonte armiger Gurney, 1927; Onychocamptus armiger (Lang, 1948); Echinolaophonte armiger f. typica (Lang, 1965));
E. brevispinosa (Sars, 1908) (= Laophonte brevispinosa Sars, 1908; Onychocamptus brevispinosus (Lang, 1948));
E. briani Lang, 1965 (= E. armiger f. briani Lang, 1965);
E. gladiator (Vervoort, 1962) (= Onychocamptus gladiator Vervoort, 1964);
E. hystrix (Brian, 1928) (= Laophonte hystrix Brian, 1928; L. steueri van Douwe, 1929; E. armiger (Norman, 1941); O. armiger (Lang, 1948, Vervoort, 1964); E. armiger f. typica (Lang, 1965;
E. longantennata Apostolov, 1990;
E. mirabilis (Gurney, 1927) (= Laophonte mirabilis Gurney, 1927; Onychocamptus mirabilis (Lang, 1948));
E. musa sp. nov. (present contribution);
E. oshoroensis Itô, 1969;
E. tetracheir Mielke, 1981;
E. villabonae Fuentes-Reinés and Suárez-Morales, 2017.
Echinolaophonte musa sp. nov.
Locus typicus
Type material
Adult female holotype (NIBRIV0000888158) dissected on 12 slides (Rostrum and A1; A2; mandible; maxillule; maxilla; maxilliped; P1; P2; P3; P4; P5; urosome), Munseom Islet, Jeju Island, Korea, coll. H.S. Rho, 01 Oct. 2002. Male allotype (NIBRIV0000888157) dissected on 12 slides (Rostrum; A1; A2; maxilla; maxilliped; P1; P2; P3; P4; P5; cphth; urosome). Paratypes: two females and five males, undissected, ethanol-preserved in vial (NIBRIV0000888156) and two females and four males, as above (MABIKCR00248285-CR00248290).
Additional studied material
1 female and 1 male, ethanol-preserved, Munseom Islet, Jeju Island, Korea, coll. H.S. Rho, 06 Oct. 2002; 1 male, undissected, ethanol-preserved, Sagyeri, Jeju Island, 4 Sep 2008; 2 females and 1 male, undissected, ethanol-preserved, Sungsanpo, Jeju Island, 12 May, 2013, coll. S.H. Kim, deposited at the National Marine Biodiversity Institute of Korea (reg. no. MADBK 721114-001).
Description of the female
Habitus (Figs
Cephalothorax (Figs
Urosome (Figs
Antennule (Figs
Antenna (Fig.
Mandible (Fig.
Maxillule (Fig.
Maxilla (Fig.
Maxilliped (Fig.
P1 (Fig.
P2 (Fig.
P3 (Fig.
P4 (Fig.
| Thoracopod | Exopod | Endopod |
|---|---|---|
| P2 | 0 1 123 | 0 120 |
| P3 | 0 1 223 | 0 220 |
| P4 | 0 1 222 | 0 120 |
P5 (Fig.
Description of male
Total body length 648.5 μm (642.4–721.2 μm, mean = 681.8 μm, n = 10), measured from anterior margin of rostrum to posterior margin of caudal rami (Fig.
Urosome (Figs
Antennule (Fig.
Setal formula: 1-[1], 2-[8], 3-[7], 4-[11 + ae], 5-[0], 6-[1], 7-[8 + acrothek (2 + ae)].
Antenna, mouthparts and P1, P2 and P4 as in female.
P3 (Fig.
P5 (Fig.
P6 (Fig.
Etymology
The epitheton originates from the Korean word ‘mu-sa [무사]’, which means “warrior”.
Phylogenetic analysis
Currently, the taxon Echinolaophonte encloses 16 species: E. armiger, E. brevispinosa, E. briani, E. gladiator, E. horrida, E. hystrix, E. longantennata, E. minuta, E. mirabilis, E. mordoganensis, E. musa sp. nov., E. oshoroensis, E. tetracheir, E. tropica, E. veniliae and E. villabonae. These are in the following referred to as “Echinolaophonte–CS” (“current status”) to distinguish them from both
Matrix listing the 135 morphological characters used in the here presented phylogenetic analysis. 1 = supposed apomorphies; 0 = supposed plesiomorphies; 1 = supposed convergent apomorphies. Vertical arrows in characters 31 and 32 point towards a further deviation in E. oshoroensis. For character state justification, see character discussion.
| No. | No. Convergences | Character/species (1 = apomorphy; 0 = plesiomorphy; 1 = supposed convergence; ? = no data available) | Echinolaophonte-CS | ||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Heterolaophonte minuta | Coullia | Hemilaophonte janinae | Xanthilaophonte | Parechinolaophonte tropica | Pseudechinolaophonte minuta | Pseudechinolaophonte veniliae | Pseudechinolaophonte mordoganensis | Echinolaophonte armiger | Echinolaophonte gladiator | Echinolaophonte brevispinosa | Echinolaophonte horrida | Echinolaophonte oshoroensis | Echinolaophonte villabonae | Echinolaophonte briani | Echinolaophonte hystrix | Echinolaophonte tetracheir | Echinolaophonte musa sp. nov. | Echinolaophonte mirabilis | |||
| 1 |
P1 of characteristic laophontid shape (cf. |
1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | |
| 2 | P2 female enp(-2) with at most 1 inner seta | 0 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | |
| 3 | P3 female enp(-2) with at most 2 inner setae | 0 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | |
| 4 | P1 exopod at most 2-segmented | 0 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | |
| 5 | P1 coxa slender, elongate | 0 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | |
| 6 | P1 basis slender, elongate | 0 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | |
| 7 | P3 female enp(-2) without outer spine | 0 | 0 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | |
| 8 | A1 female 6-segmented | 0 | 0 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | |
| 9 | P5 female benp with at most 4 setae | 0 | 0 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | |
| 10 | P4 female enp(-2) without outer spine | 0 | 0 | 0 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | |
| 11 | P5 female exopod with at most 3 setae | 0 | 0 | 0 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | |
| 12 | Preanal somite dorsally with pseudoperculum formed by cuticular spikes | 0 | 0 | 0 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | |
| 13 | Rostrum narrowed | 0 | 0 | 0 | 0 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | |
| 14 | Mxp syncoxa as long as or slightly shorter than basis | 0 | 0 | 0 | 0 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | |
| 15 | Cphth with dorsal cuticular ridge crossed by two furrows | 0 | 0 | 0 | 0 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | |
| 16 | 1(?) | Cphth laterally extended | 0 | 0 | 0 | 0 | 1 | 0 | 0 | 0 | 1 ? | 1 ? | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 ? | 1 ? |
| 17 | Cphth on lateral posterior corners with backwardly directed projections | 0 | 0 | 0 | 0 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | |
| 18 | 1st abdominal somite with small spinulose cuticular structure | 0 | 0 | 0 | 0 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | |
| 19 | 2nd abdominal somite with small spinulose cuticular structure | 0 | 0 | 0 | 0 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | |
| 20 | P5 female baseoendopod and exopod fused | 0 | 0 | 0 | 0 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | |
| 21 | Cphth dorsally with strong cuticular structure centrally on posterior margin | 0 | 0 | 0 | 0 | 0 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | |
| 22 | Free body somites except preanal somite and telson with cuticular structures on posterior margin | 0 | 0 | 0 | 0 | 0 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | |
| 23 | Cphth dorsally with spinulose, broad projection bearing 2-4 apical spikes | 0 | 0 | 0 | 0 | 0 | 1 | 1 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | |
| 24 | Cphth rectangular, almost square | 0 | 0 | 0 | 0 | 0 | 1 | 1 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | |
| 25 | P2-bearing somite dorsally with pair of strong spikes standing close together | 0 | 0 | 0 | 0 | 0 | 1 | 1 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | |
| 26 | P3-bearing somite dorsally with pair of strong spikes standing close together | 0 | 0 | 0 | 0 | 0 | 1 | 1 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | |
| 27 | P4-bearing somite dorsally with pair of strong spikes standing close together | 0 | 0 | 0 | 0 | 0 | 1 | 1 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | |
| 28 | P5-bearing somite dorsally with pair of strong spikes standing close together | 0 | 0 | 0 | 0 | 0 | 1 | 1 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | |
| 29 | 1st abdominal somite (= posterior GDS) with dorsal sclerotized clasp-like area bearing 2 spikes | 0 | 0 | 0 | 0 | 0 | 1 | 1 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | |
| 30 | 2nd abdominal somite with dorsal sclerotized clasp-like area bearing 2 spikes | 0 | 0 | 0 | 0 | 0 | 1 | 1 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | |
| 31 | 2 | 1st abdominal somite (= posterior GDS) with epimeres extended laterally | 0 | 0 | 0 | 0 | 0 | 1 | 1 | 1 | 0 | 0 | 1 | 1 | 1 ↑ | 0 | 0 | 0 | 0 | 0 | 1 |
| 32 | 3 | 2nd abdominal somite with epimeres extended laterally | 0 | 0 | 0 | 0 | 0 | 1 | 1 | 1 | 0 | 0 | 1 | 1 | 1 ↑ | 0 | 0 | 0 | 0 | 0 | 1 |
| 33 | Pseudoperculum developed as sclerotized clasp-like area bearing spikes | 0 | 0 | 0 | 0 | 0 | 1 | 1 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | |
| 34 | A2 endopodal surface seta with strongly derived tip | 0 | 0 | 0 | 0 | 0 | 1 | 1 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | |
| 35 | P2 outer basal seta longer than exp-1 and exp-2, biplumose | 0 | 0 | 0 | 0 | 0 | 1 | 1 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | |
| 36 | P5 baseoendopod female with 2 setae | 0 | 0 | 0 | 0 | 0 | 1 | 1 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | |
| 37 | Cphth dorsal process square, spinulose, with 2 strong spikes, each outwardly accompained by 2 small ones | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | |
| 38 | A1 female 2nd segment 1 subapical outer seta remarkably elongated, longer that remaining segments together | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | |
| 39 | A2 endopod: surface seta comb-like at distal half; not tapering gradually | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | |
| 40 | P5 female baseoendopodal setae not reaching apical margin of exopod | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | |
| 41 | Posterior half of GDS lateral wing-like epimeres strongly pronounced | 0 | 0 | 0 | 0 | 0 | 1 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | |
| 42 | 2nd abdominal somite lateral wing-like epimeres strongly pronounced | 0 | 0 | 0 | 0 | 0 | 1 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | |
| 43 | Pseudoperculum consisting of paired y-shaped spikes accompanied each by single spike | 0 | 0 | 0 | 0 | 0 | 1 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | |
| 44 | 4 | A2 allobasis without abexopodal seta | 0 | 0 | 0 | 0 | 0 | 1 | 1 | 0 | 0 | 1 | 0 | 0 | 0 | 0 | 1 | 0 | 0 | 0 | 0 |
| 45 | Md palpus lost exopodal seta (= with 4 setae) | 0 | 0 | 0 | 0 | 0 | 1 | 1 | 0 | 0 | ? | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | |
| 46 | 5 | Mxp syncoxa with 1 apical seta | 0 | 0 | 0 | 0 | 0 | 1 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 0 | 0 | 0 | 0 |
| 47 | Cphth dorsal process square, spinulose, with 4 strong spikes | 0 | 0 | 0 | 0 | 0 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | |
| 48 | A2 endopod seta with club-shaped, apically pinnate tip | 0 | 0 | 0 | 0 | 0 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | |
| 49 | 6 | Mxl coxa with 1 apical seta | 0 | 0 | 0 | 1 | 0 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| 50 | 7 | Mxl basis with 1 apical seta | 0 | 0 | 0 | 1 | 0 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| 51 | Cphth dorsal process spinulose, elongate, with rounded apex carrying 4 spikes | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | |
| 52 | A2 endopod seta with square-cut, fork-like tip | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | |
| 53 | P3 male endopodal apophysis with indentation near its tip | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | |
| 54 | Cphth with single spur dorsally on posterior margin | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | |
| 55 | Whole body surface densely covered with fine cuticular structures | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | |
| 56 | 8 | Cphth laterally protruded | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 1 |
| 57 | Cphth dorsal spur broad, rather short | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | |
| 58 | 9 | Female GDS laterally of slightly inflated aspect | 0 | 0 | 0 | 1 | 0 | 0 | 0 | 0 | 1 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| 59 | Pedigerous and first 2 abdominal somites dorsally with small spiny processes on posterior margin | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | |
| 60 | Dense body coverage developed into tiny denticles | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | |
| 61 | P4-bearing somite dorsally with 4 spiny processes standing pairwise together | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | |
| 62 | Anterior half of female GDS with pair of spiny processes fused at their bases | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | |
| 63 | Posterior half of GDS and second abdominal somite dorsally with spiny processes standing close together | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | |
| 64 | Dense body coverage developed into short setules | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | |
| 65 | Cphth lateral protrusions produced into pair of narrow, backwardly directed cuticular jags | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | |
| 66 | Mxp strong, allobasis swollen on inner margin, claw massive, curved about 90° | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | |
| 67 | 10 | P3 female exp-3 with 2 outer spines | 0 | 0 | 0 | 1 | 1 | 0 | 0 | 0 | 0 | 1 | 0 | 0 | 0 | 1 | 0 | 0 | 0 | 0 | 0 |
| 68 | P2-bearing somite with paired dorsal processes | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | |
| 69 | P3-bearing somite with paired dorsal processes | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | |
| 70 | P4-bearing somite with paired dorsal processes | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | |
| 71 | P5-bearing somite with paired dorsal processes | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | |
| 72 | 11 | P6-bearing somites with paired dorsal processes | 0 | 0 | 0 | 0 | 0 | 1 | 1 | 1 | 0 | 0 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 |
| 73 | 1st abdominal somite with paired dorsal processes | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | |
| 74 | 2nd abdominal somite with paired dorsal processes | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | |
| 75 | Cphth laterodistally extended cheek-like | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 1 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | |
| 76 | Rostrum elongate, with rounded tip | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 1 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | |
| 77 | P3 male exopod powerfully developed | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 1 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | |
| 78 | P3 male exp-2 outer spine massive, s-shaped | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 1 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | |
| 79 | Tip of rostrum minutely emarginated | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | |
| 80 | Cphth: lateral “cheeks” bulging considerably | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | |
| 81 | Rostrum basally remarkably constricted | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | |
| 82 | 12 | Cphth spur strongly tapering apically, apical half quite narrow | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 1 | 0 | 1 | 0 | 0 | 0 | 0 |
| 83 | Pseudoperculum consisting of 4 tridenticulated processes | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | |
| 84 | 13 | P1 exopod reduced in length, not even reaching half the length of enp-1 | 0 | 0 | 0 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 1 | 0 | 0 | 0 | 0 | 0 | 0 |
| 85 | P3 male enp-2 apophysis with acute jag basally on inner margin | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | |
| 86 | P2-bearing somite dorsal processes denticulated | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | |
| 87 | P3-bearing somite dorsal processes denticulated | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | |
| 88 | P4-bearing somite dorsal processes denticulated | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | |
| 89 | P5-bearing somite dorsal processes denticulated | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | |
| 90 | Dorsal cuticular processes of P6-bearing somite (= female anterior half of GDS) denticulated | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | |
| 91 | Dorsal cuticular processes of 1st abdominal somite (= female posterior half of GDS) denticulated | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | |
| 92 | Dorsal cuticular processes of 2nd abdominal somite denticulated | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | |
| 93 | 1st abdominal somite (= posterior GDS) lateral wing-like epimeres extended completely reduced | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | |
| 94 | 2nd abdominal somite lateral wing-like epimeres extended completely reduced | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | |
| 95 | 14 | Cphth spur laterally with tufts of long and fine setules | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 0 | 1 | 0 | 1 | 1 | 1 |
| 96 | P2-bearing somite with lateral cuticular processes | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | |
| 97 | P3-bearing somite with lateral cuticular processes | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | |
| 98 | P4-bearing somite with lateral cuticular processes | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | |
| 99 | P5-bearing somite with lateral cuticular processes | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | |
| 100 | 1st abdominal somite (= posterior half of female GDS) with lateral cuticular processes | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | |
| 101 | 2nd abdominal somite with lateral cuticular processes | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | |
| 102 | P3 exopod male remakably strengthened | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | |
| 103 | 15 | P3 endopod male 2-segmented | 0 | 0 | 0 | 1 | 1 | 0 | 0 | 0 | 1 | ? | 0 | 0 | 0 | 1 | 1 | 1 | 1 | 1 | 1 |
| 104 | 16 | P3 male endopod lost sexual dimorphism | 0 | 0 | 0 | 1 | 1 | 0 | 0 | 0 | 1 | ? | 0 | 0 | 0 | 1 | 1 | 1 | 1 | 1 | 1 |
| 105 | Rostrum slightly trapezoid, constricted basally and broadening apically, rather flat/concave apical margin | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 1 | 1 | 0 | 0 | 0 | |
| 106 | Cphth laterally with intricate cuticular ornamentation | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 1 | 1 | 0 | 0 | 0 | |
| 107 | Female GDS dorsally with cuticular “ring” | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 1 | 1 | 0 | 0 | 0 | |
| 108 | 1st abdominal somite (= posterior half of female GDS) dorsally with strengthened, spinules-bearing cuticular area | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 1 | 1 | 0 | 0 | 0 | |
| 109 | 2nd abdominal somite dorsally with strengthened, spinules-bearing cuticular area | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 1 | 1 | 0 | 0 | 0 | |
| 110 | Female pseudoperculum consisting of 2 bi- or tri-denticulate processes, laterally accompanied each by 2 spikes | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 1 | 1 | 0 | 0 | 0 | |
| 111 | Cphth dorsal spur robust, short, with 2 dorsal notches | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 0 | ? | 0 | 0 | 0 | |
| 112 | Cphth: lateral cuticular ornamentation considerably pronounced | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 0 | ? | 0 | 0 | 0 | |
| 113 | Rostrum granular on anterior half | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 0 | ? | 0 | 0 | 0 | |
| 114 | Preanal somite with 2 spinulose rows in front of pseudoperculum | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | ? | 0 | 0 | 0 | |
| 115 | Rostrum elongate, with bifurcated tip | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 1 | 1 | |
| 116 | CR at least 3,5 times longer than broad | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 1 | 1 | |
| 117 | 17 | P3 outer basal seta of composite shape | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 0 | 1 | 0 | 1 | 1 | 1 |
| 118 | 18 | P4 outer basal seta of composite shape | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 0 | 0 | 0 | 1 | 1 | 1 |
| 119 | 1st abdominal somite (= posterior half of female GDS): processes arising from H-like fortification | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 0 | 0 | |
| 120 | 2nd abdominal somite: processes arising from H-like fortification | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 0 | 0 | |
| 121 | Pseudoperculum consisting of 4 palmate processes carrying each 5-6 “fingers” | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 0 | 0 | |
| 122 | Cphth lateral processes elongated, slender | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 1 | |
| 123 | Cphth anteriorly with moderate dorsal process | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 1 | |
| 124 | Cphth centrally with moderate dorsal process | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 1 | |
| 125 | CR at least 5,5 times longer than broad | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 1 | |
| 126 | Cphth lateral processes backwardly curved | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 0 | |
| 127 | P2-bearing somite of female: processes strongly elongate and bifurcate | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 0 | |
| 128 | P3-bearing somite: processes strongly elongate and bifurcate | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 0 | |
| 129 | P4-bearing somite: processes strongly elongate and bifurcate | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 0 | |
| 130 | P5-bearing somite: processes strongly elongate and bifurcate | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 0 | |
| 131 | P6-bearing somite: processes strongly elongate and bifurcate | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 0 | |
| 132 | 1st abdominal somite: processes strongly elongate and bifurcate | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 0 | |
| 133 | 2nd abdominal somite: processes strongly elongate and bifurcate | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 0 | |
| 134 | P2-bearing somite dorsal processes long, bearing 3 long setules basally | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | |
| 135 | 2nd abdominal somite dorsal proceses fused basally, with 2 denticles basally and centrally, and with 2 long setules | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | |
Eightteen out of 135 characters (= 13.3%) emerged as convergent deviations. They mostly distribute heterogeneously over the species and are set in underlined bold italics in Table
The results of the phylogenetic analysis are discussed in detail below. The resulting phylogenetic relationships are presented in Fig.
List of nodes and assigned clades/taxa and apomorphies shown in Fig.
| Node | Clade/taxon | Included studied taxa | No. apomorphies |
|---|---|---|---|
| A | Laophontidae | all studied taxa | 1 |
| B | Coullia–Echinolaophonte clade | Coullia, Hemilaophonte, Parechinolaophonte gen. nov., Pseudechinolaophonte gen. nov., Echinolaophonte | 2, 3, 4, 5, 6 |
| C | Hemilaophonte–Echinolaophonte clade | Hemilaophonte, Parechinolaophonte gen. nov., Pseudechinolaophonte gen. nov., Echinolaophonte | 7, 8, 9 |
| D | Xanthilaophonte–Echinolao-phonte clade | Parechinolaophonte gen. nov., Pseudechinolaophonte gen. nov., Echinolaophonte | 10, 11, 12 |
| E | Parechinolaophonte gen. nov.–Echinolaophonte clade | Parechinolaophonte gen. nov., Pseudechinolaophonte gen. nov., Echinolaophonte | 13, 14 |
| F | Parechinolaophonte gen. nov. | Parechinolaophonte tropica gen. et comb. nov. | 15, 16?, 17, 18, 19, 20, 67, 103, 104 |
| G | Pseudechinolaophonte gen. nov.–Echinolaophonte clade | Pseudechinolaophonte gen. nov., Echinolaophonte | 21, 22 |
| H | Pseudechinolaophonte gen. nov. | Pseudechinolaophonte minuta gen. et comb. nov., Ps. mordoganensis gen. et comb. nov., Ps. veniliae gen. et comb. nov. | 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 72 |
| I | Pseudechinolaophonte mordoganensis gen. et comb. nov. | Pseudechinolaophonte mordoganensis gen. et comb. nov. | 37, 38, 39, 40 |
| J | Pseudechinolaophonte minuta–venilia clade | Pseudechinolaophonte minuta gen. et comb. nov., Ps. veniliae gen. et comb. nov. | 41, 42, 43, 44, 45, 46 |
| K | Pseudoechinolaophonte minuta gen. et comb. nov. | Pseudechinolaophonte minuta gen. et comb. nov. | 47, 48, 49, 50 |
| L | Pseudoechinolaophonte veniliae gen. et comb. nov. | Pseudechinolaophonte veniliae gen. et comb. nov. | 51, 52, 53 |
| M | Echinolaophonte | E. armiger, E. gladiator, E. brevispinosa, E. horrida, E. oshoroensis, E. villabonae, E. briani, E. tetracheir, E. musa sp. nov., E. mirabilis | 54 |
| N | Echinolaophonte armiger–gladiator clade | Echinocletodes armiger, E. gladiator | 16 ?, 55, 56, 57, 58, 59 |
| O | Echinolaophonte armiger | Echinolaophonte armiger | 60, 61, 62, 63, 103, 104 |
| P | Echinolaophonte gladiator | Echinolaophonte gladiator | 44 , 64, 65, 66, 67 |
| Q | Echinolaophonte brevispinosa–mirabilis clade | Echinolaophonte brevispinosa, E. horrida, E. oshoroensis, E. villabonae, E. briani, E. tetracheir, E. musa sp. nov., E. mirabilis | 68, 69, 70, 71, 72, 73, 74 |
| R | Echinolaophonte brevispinosa–oshoroensis clade | Echinolaophonte brevispinosa, E. horrida, E. oshoroensis | 31 , 32, 75, 76, 77, 78 |
| S | Echinolaophonte brevispinosa | Echinolaophonte brevispinosa | 79, 80 |
| T | Echinolaophonte horrida–oshoroensis clade | Echinolaophonte horrida, E. oshoroensis | 81, 82, 83, 84, 85 |
| U | Echinolaophonte horrida | Echinolaophonte horrida | 86, 87, 88, 89, 90, 91, 92 |
| V | Echinolaophonte oshoroensis | Echinolaophonte oshoroensis | 93, 94, 95, 96, 97, 98, 99, 100, 101, 102, 117, 118 |
| W | Echinolaophonte villabonae–mirabilis clade | Echinolaophonte villabonae, E. briani, E. tetracheir, E. musa sp. nov., E. mirabilis | 103 , 104 |
| X | Echinolaophonte villabonae–briani clade | Echinolaophonte villabonae, E. briani | 105, 106, 107, 108, 109, 110 |
| Y | Echinolaophonte villabonae | Echinolaophonte villabonae | 67 , 111, 112, 113 |
| Z | Echinolaophonte briani | Echinolaophonte briani | 44 , 46, 82, 95, 114, 117 |
| AA | E. tetracheir–mirabilis clade | Echinolaophonte tetracheir, E. musa sp. nov., E. mirabilis | 95 , 115, 116, 117, 118 |
| BB | Echinolaophonte tetracheir | Echinolaophonte tetracheir | 119, 120, 121 |
| CC | Echinolaophonte musa sp. nov.–mirabilis clade | Echinolaophonte musa sp. nov., E. mirabilis | 16 ?, 56, 122, 123, 124, 125 |
| DD | Echinolaophonte musa sp. nov. | Echinolaophonte musa sp. nov. | 126, 127, 128, 129, 130, 131, 132, 133 |
| EE | Echinolaophonte mirabilis | Echinolaophonte mirabilis | 31 , 32, 134, 135 |
The results suggest that Echinolaophonte–CS consists of several subordinated clades that complicate an unambiguous characterisation of the genus (Fig.
Parechinolaophonte gen. nov.
Diagnosis
Laophontidae T. Scott, 1905. Body elongate, cylindrical, podoplean boundary between pro- and urosome inconspicuous. Whole body minutely punctate. Sexual dimorphism in A1, P5 and P6; female with GDS. Cphth reaching about 1/3 of total body length; lateral margins of cphth extended outwardly, triangular; distal outer edges of cphth with paired backwardly directed protrusions, dorsally with longitudinal cuticular ridge crossed by 2 furrows. Rostrum fused to cphth, laterally constricted, almost square. Body somites without pronounced dorsal cuticular processes; abdominal somites, except telson, with weakly developed cuticular spinulose structures on posterior margins. Pseudoperculum weakly developed, consisting of 4 small protrusions bearing several fine spinules apically. CR about twice as long as broad, with 7 setae (cf.
Etymology
The generic name is composed of the Greek prefix pará-, meaning similar and the generic name Echinolaophonte. Gender: feminine.
Type and only species
Parechinolaophonte tropica (Ummerkutty, 1970), gen. et comb. nov., by original designation.
Pseudechinolaophonte gen.nov.
Diagnosis
Laophontidae T. Scott, 1905. Body elongate, cylindrical, podoplean boundary between pro- and urosome inconspicuous. Sexual dimorphism in the A1, P3, P5 and P6; female with GDS. Cphth almost squarish, reaching about 1/3 of total body length; dorsally with spinulose, broad cuticular projection bearing 2–4 apical spikes on posterior margin (cf. Fig.
Schematic depiction of A. Pseudechinolaophonte minuta gen. et comb. nov.; B. Echinolaophonte armiger and C. Echinolaophonte horrida, illustrating and exemplifying the general shape of the cuticular structures located dorsally on the cephalothorax and free body somites of the closely-related taxa treated in the present contribution. The assigned numbers reflect the corresponding morphological characters as listed in Table
Etymology
The generic name is composed of the Greek prefix pseudo-, meaning false or fake and the generic name Echinolaophonte. Gender: feminine.
Type species
Pseudechinolaophonte minuta (Cottarelly & Forniz, 1991), gen. et comb. nov., by original designation.
Additional species
Ps. mordoganensis (Kuru, Sönmez & Karaytug, 2019) gen. et comb. nov., Ps. veniliae (Cottarelly, Forniz & Bascherini, 1992), gen. et comb. nov.
Restructuring Echinolaophonte Nicholls, 1941
After the exclusion of Parechinolaophonte tropica gen. et comb. nov., Pseudechinolaophonte minuta gen. et comb. nov., Ps. mordoganensis gen. et comb. nov. and Ps. veniliae gen. et comb. nov. from Echinolaophonte–CS, the genus Echinolaophonte retains 11 species (Fig.
Phylogenetic relationships within Echinolaophonte
Echinolaophonte splits into two main subordinated clades, namely the armiger–gladiator clade enclosing E. armiger and E. gladiator (Fig.
The brevispinosa–mirabilis clade is characterised by seven unambiguous autapomorphies (Table
Establishment of Echinolaophonte briani Lang, 1965
The status of Echinolaophonte hystrix and Laophonte steueri van Douwe, 1929
Echinolaophonte hystrix had been synonymised with E. armiger by
The here presented phylogenetic analysis aimed at elucidating the systematic relationship of both E. hystrix and L. steueri. However, the available information is scarce and the descriptions of both species are rather imprecise and incomplete. Though, the synonymisation of L. steueri with E. hystrix is tentatively confirmed here (see Discussion); however and despite some indications for an allocation of E. hystrix into the villabonae–briani clade, due to the gap of detailed information, the systematic position of E. hystrix within Echinolaophonte remains unclear (Fig.
Diagnostic key to the genera and species of Echinolaophonte and the here established new genera (note: E. longantennata was excluded from the analysis due to lack of data)
| 1 | Cphth without strong, cuticular dorsal structure centrally; free body somites, except pre-anal somite and telson without well-developed cuticular structures | 2 |
| – | Cphth with strong cuticular dorsal structure centrally; free body somites, except pre-anal somite and telson with well-developed cuticular structures | 3 |
| 2 | P2 exp-2 with inner seta; P1 exp reaching over middle of enp- | Parechinolaophonte tropica gen. et. comb. nov. |
| 3 | Cphth rectangular, almost square; P2–P6-bearing somites dorsally with pair of with spikes that are basally connected to each other; A2 enp with 1 spine bearing strongly derived tip 4 | Pseudechinolaophonte gen. nov. |
| – | Cphth not square; P2–P6-bearing somites dorsally with pair of basally separated processes instead of pair of connected spikes; A2 enp without blunt-tip-bearing spine 6 | Echinolaophonte |
| 4 | P4 exp-3 with 4 setae/spines | 5 |
| – | A2 enp derived seta comb-like at distal half; P4 exp-3 with 5 setae/spines | Ps. mordoganensis comb. nov. |
| 5 | A2 enp derived seta club-shaped; P2 exp-3 twice as long as exp-3; CR 2.0 times longer than wide | Ps. minuta comb. nov. |
| – | A2 enp derived seta with a trifid tip; P2 exp-3 only slightly longer than exp-3; CR 1.5 times longer than wide | Ps. veniliae comb. nov. |
| 6 | Paired dorsal processes tiny; cphth dorsal spur with broad base | 7 |
| – | Paired dorsal processes strongly developed; cphth dorsal spur with narrow base | 8 |
| 7 | P3 exp-3 with 7 setae/spines | E. armiger |
| – | P3 exp-3 with 6 setae/spines | E. gladiator |
| 8 | Cphth laterodistally exended cheek-like; Ro elongate, with rounded tip | 9 |
| – | These characters not combined | 11 |
| 9 | P2 exp-3 with inner seta; CR at least 2 times as long as wide | 10 |
| – | P2 exp-3 without inner seta; CR at most 2 times as long as wide | E. oshoroensis |
| 10 | Rostrum with rounded tip; P1 exp not reaching middle of enp-1 | E. horrida |
| – | Rostrum with bilobed tip; P1 exp reaching middle of enp-1 | E. brevispinosa |
| 11 | Rostrum slightly trapezoid, broadening apically; Cphth with lateral cuticular ornamentation | 12 |
| – | Rostrum narrow and elongate; Cphth without lateral cuticular ornamentation | 14 |
| 12 | P3 exp-3 with 7 setae/spines | 13 |
| – | P3 exp-3 with 6 setae/spines | E. villabonae |
| 13 | Female P2 enp-1 as long as enp-2; male P3 with sexual dimorphism | E. hystrix |
| – | Female P2 enp-1 much shorter than enp-2; male P3 without sexual dimorphism | E. briani |
| 14 | CR at most 4 times longer than wide; female P4 enp-2 reaching beyond exp-2 | E. tetracheir |
| – | CR at least 5 times longer than wide; female P4 enp-2 not reaching exp-2 | 15 |
| 15 | P2–P6-bearing somites with strongly elongate and bifurcate processes; Rostrum without sexual dimorphism | E. musa sp. nov. |
| – | P2–P6-bearing somites without strongly elongate and bifurcate processes; Ro with sexual dimorphism | E. mirabilis |
Discussion
Echinolaophonte: a systematic tangle
The statement of
The topic began at the end of the 18th century:
Nowadays, Cleta is synonymised with Laophontopsis Sars, 1908 and, thus, assigned to the Laophontopsidae Huys & Willems, 1989 (cf.
It was
Nineteen years after
A further obstacle is that, since the establishment of Echinolaophonte by
Echinolaophonte was proposed by
Phylogenetic analysis
Validity of the generic diagnosis from
In a first step, the 15 species (E. longantennata was excluded from the analysis) were examined in relation to Nicholl’s (1941) generic diagnosis, i.e. the above listed characters I–VI. These constitute remarkable morphological deviations and, thus, are seen here as phylogenetically highly relevant.
Character I, presence of a single, well-developed spur on the posterior margin of the cphth (cf. Figs
“…a chitinous process nearly quadrangular, the posterior margin of which is provided with strong spines and many thin setae lined on dorsal surface and along margins.” (
That structure is interpreted here as having undergone a different further development than the single acute spur in Echinolaophonte. It is, therefore, listed as distinct apomorphy (Table
Finally, the last of the four species, E. tropica, presents neither a single acute spur nor a squarish spinulose and setulose structure; instead, it presents two dorsal furrows crossing a longitudinal cuticular ridge on its cphth (cf.
Character II, presence of dorsolateral pairs of processes on all free body somites, except penultimate somite and telson (cf. Fig.
Character III, a large and expanded rostrum (cf. Fig.
Characters IV (female A1 6-segmented), V (P1 with long and slender coxa, basis and enp-1; exopod 2-segmented, short, almost reaching half the length of enp-1) and VI (female P5 with narrow baseoendopod that carries four setae; exopod elongate, with three setae) are confirmed for all species. It has to be objected, however, that at least characters IV and V are not exclusively found in Echinolaophonte–CS; for instance, a 6-segmented female A1 (character IV) is also found in the laophontids Carraroenia McCormack, 2006, Hemilaophonte janinae Jakubisiak, 1933, Psammoplatypus Lee & Huys, 1999, Xanthilaophonte, and Coullia (part.), a P1 as described in character V is also present at least in Hemilaophonte janinae, Xanthilaophonte and Coullia and a female P5 baseoendopod bearing four setae is also present in Hemilaophonte janinae and Xanthilaophonte (e.g.
Therefore, it is concluded here that, based on Nicholl’s (1941) generic diagnosis, characters I–VI are not shared by all Echinolaophonte–CS species or they are present also in other laophontid genera.
Relationship of Echinolaophonte–CS with other laophontid genera
In the following, a detailed character comparison is presented. For that purpose, 135 morphological characters were selected (Table
Discussion of the membership of all here treated taxa in a monophylum Laophontidae is not an objective of the contribution at hand. Therefore, it is simply underlined by just one unambiguous apomorphy, the characteristic laophontid shape of the P1 (Table
Compared with the first outgroup Heterolaophonte minuta, a set of five apomorphies characterise Coullia, Hemilaophonte janinae, Xanthilaophonte and Echinolaophonte–CS (Table
Character 2, female P2 endopod with at most 1 inner seta [with 2 setae]: whilst H. minuta retains 2 inner setae on the female P2 endopod, Echinolaophonte–CS and Xanthilaophonte lost 1 and Coullia and Hemilaophonte janinae lost both inner setae.
Character 3, female P3 endopod with at most 2 inner setae [with 3 setae]: as for character 2, H. minuta retains the ancestral state of 3 inner setae, whilst Echinolaophonte–CS and Xanthilaophonte lost 1 seta, Coullia lost 2 and Hemilaophonte janinae lost all three setae.
Character 4, P1 exopod at most 2-segmented [3-segmented]: in H. minuta the P1 presents the ancestral 3-segmented exopod; the exopod is (at most) 2-segmented in Coullia, Hemilaophonte janinae, Xanthilaophonte and Echinolaophonte–CS.
Characters 5 and 6, P1 coxa and basis elongate and slender [coxa short, squarish or broader than long]: H. minuta presents the rather ancestral state of a short coxa and basis. In contrast, in Coullia, Hemilaophonte janinae, Xanthilaophonte and Echinolaophonte–CS, both the coxa and the basis are remarkably elongated.
Characters 2–6 clearly separate the Coullia–Echinolaophonte–CS clade from Heterolaophonte minuta. It remains, however, unclear, to what extent that clade constitutes a monophyletic unity. Other taxa like, for example, Carraroenia and Psammoplatypus, also share at least single deviations with the Coullia–Echinolaophonte–CS clade. Nonetheless, as the here presented study explicitly focuses on the systematic status of Echinolaophonte–CS, the expansion of the phylogenetic analysis by adding further supraspecific taxa is beyond the scope of the present analysis.
The first branch-off from the Coullia–Echinolaophonte–CS clade is Coullia. It differs from the Hemilaophonte–Echinolaophonte–CS clade (Fig.
Character 7, female P3 enp-2 without outer spine [outer spine still present]: Hemilaophonte janinae, Xanthilaophonte and Echinolaophonte–CS have lost the outer spine on the female P3 enp-2, which is still present in Coullia.
Character 8, female A1 6-segmented [at least 7-segmented]: Hemilaophonte janinae, Xanthilaophonte and Echinolaophonte–CS show a 6-segmented female antennule; the ae-bearing fourth segment is followed by 2 segments only. In Coullia, all except one species also present a 6-segmented female A1 (including the here exemplified C. tongariki). Nonetheless, as C. platychelipusoides (Noodt, 1958) still retains 7 segments in the female A1 (Noodt, 1958) — the ae-bearing fourth segment followed by 3 segments, the reduction of one antennular segment in the remaining Coullia species must be regarded as further deviation within Coullia and is, therefore, interpreted here as independent and convergent development.
Character 9, female P5 baseoendopod with at most 4 setae [with at least 5 setae]: At least C. tongariki and C. platychelipusoides bear five setae on the female P5 baseoendopod, whilst in Hemilaophonte janinae, Xanthilaophonte and Echinolaophonte–CS, only four setae are retained.
The monophyletic characterisation of Coullia is not pursued here. Contrariwise, the exclusive presence of the derived characters 7–9 in Hemilaophonte janinae, Xanthilaophonte and Echinolaophonte–CS support the hypothesis of these taxa being sister groups, with characters 7–9 constituting unambiguous synapomorphies.
Without aiming to provide an extensive characterisation of Hemilaophonte janinae, its distinct phylogenetic status may probably be supported by the shape, size and ornamentation of the rather short and blunt P2–P4; especially the (female) endopods stick out because of their small size that scarcely reaches the length of the respective exp-1. These derived features are missing in Xanthilaophonte and Echinolaophonte–CS and may probably build important hints for a future phylogenetic characterisation of Hemilaophonte janinae. It is, however, relevant in the present context, that H. janinae lacks the supposed apomorphies 10–12 (Table
Character 10, female P4 enp-2 without outer spine [outer spine still present]: Hemilaophonte janinae still retains an outer spine on the distal endopodal segment of the P4, whereas such outer spine became lost in Xanthilaophonte and in the Echinolaophonte–CS species.
Character 11, female P5 exopod with three setae [with at least four setae]: Xanthilaophonte and Echinolaophonte–CS are characterised by a strongly reduced setation of the female P5 exopod; only three setae are present. In contrast, Hemilaophonte janinae still retains six setae on the female P5 exopod.
Character 12, the presence of a peculiar pseudoperculum dorsally on the posterior margin of the pre-anal somite [no pseudoperculum]: Hemilaophonte janinae, Coullia and Heterolaophonte minuta share a pseudoperculum on the posterior margin of the pre-anal somite. In contrast, Xanthilaophonte and Echinolaophonte–CS developed a quite peculiar pseudoperculum. It carries several digitate, cuspidate processes of high inter- and even intraspecific variability (e.g.
From the above given comparative argumentation it is concluded that characters 10–12 unite Xanthilaophonte and the 15 species currently assigned to Echinolaophonte–CS. Although not providing the complex quality of, for example, Nicholl’s (1941) characters I–VI, they are exclusive deviations of them and may, therefore, support their state as monophylum.
As for Coullia and Hemilaophonte, it is neither the intention here to discuss the phylogenetic status of Xanthilaophonte. In the present context, it is, however, important to assert that, apart from single supposed convergences at lower taxonomic level (cf. Table
The Echinolaophonte–CS clade (Fig. 10 /Table 3 : node E)
As shown in Table
Character 13, rostrum narrowed, not tapering apically [rostrum with broad base, triangular]: Hemilaophonte janinae and Coullia retain the ancestral shape of the rostrum, which consists of a broad base tapering apically, giving the rostrum a triangular shape. Therefore, the narrowed rostrum as present in the Parechinolaophonte—Echinolaophonte clade (cf. Fig.
Character 14, syncoxa of the mxp as long as or only slightly shorter than the basis [syncoxa reaching only nearly half the length of the basis]: the species of the Parechinolaophonte–Echinolaophonte clade share the remarkable derived elongation of the maxilliped. It bears a syncoxa, a basis and an endopod produced into a long, curved claw. The syncoxa and basis are equally long and slender and the claw reaches or even surpasses the length of the basis. Instead, the maxillipedal syncoxa in Hemilaophonte janinae and Xanthilaophonte is short (
The first branch-off in the Parechinolaophonte–Echinolaophonte clade is Echinolaophonte tropica (Fig.
Character 15, cphth dorsally with cuticular ridge crossed by two furrows [without dorsal ridge and furrows]: Whilst the Pseudechinolaophonte–Echinolaophonte clade bears characteristic cuticular processes on the cphth, E. tropica does not. Instead, its cphth is dorsally characterised by a kind of cuticular longitudinal ridge that is crossed by two furrows (
Character 16, cphth laterally extended [not extended]: As indicated by
Character 17, cphth laterally on posterior corners with backwardly directed projections [no projections]: E. tropica is the only species assigned to the Parechinolaophonte—Echinolaophonte clade that presents peculiar backwardly directed projections laterally on the posterior corners of the cphth—an unambiguous specific apomorphy.
Characters 18 and 19, the presence of small spinulose cuticular structures on the posterior margins of the first and second abdominal somites [no such structures present]: E. tropica lacks the presence of paired processes on the body somites, except for the penultimate somite and the telson. Nonetheless, E. tropica indeed has small spinulose structures on the posterior margins of the first abdominal somite (posterior half of the female GDS), as well as on the second one. However, these structures differ remarkably from the paired cuspidate processes of Echinolaophonte sensu
Character 20, baseoendopod and exopod of the female P5 fused: E. tropica is the only species in the Parechinolaophonte—Echinolaophonte clade, whose female P5 presents a fusion of the exopod and the baseoendopod. In all remaining 14 species, the P5 exopod and the baseoendopod are separated. The fusion is hypothesised here as clear autapomorphy for E. tropica.
The clear-cut characterisation of E. tropica by six autapomorphies, combined with the absence of the apomorphies of the Pseudechinolaophonte–Echinolaophonte clade (see below) lead to the exclusion of that species from Echinolaophonte. Instead, E. tropica is transferred into a new genus Parechinolaophonte gen. nov. as Pa. tropica (Ummerkutty, 1970), gen. et comb. nov. (Fig.
The Pseudechinolaophonte—Echinolaophonte clade (Fig. 10 /Table 3 : node G)
The remaining 14 species of the Parechinolaophonte—Echinolaophonte clade, here named Pseudechinolaophonte—Echinolaophonte clade, share two unambiguous synapomorphies:
Character 21, cphth dorsally with strong cuticular structure centrally on posterior margin [no cuticular structure developed] (cf. Fig.
Character 22, free body somites, except the pre-anal one and the telson with well-developed cuticular structures on posterior margin [no cuticular structures present]: as for the cephalothoracic dorsal structure (character 21), all 14 species of the Pseudechinolaophonte–Echinolaophonte clade bear well-developed cuticular structures on the posterior margins of all, except two, free body somites. Such processes are (like the dorsal process on the cphth) absent in the above treated outgroups Heterolaophonte minuta, Coullia, Hemilaophonte janinae, Xanthilaophonte and Pa. tropica gen. et comb. nov. Therefore, they are seen as an unambiguous autapomorphic character complex of the Pseudechinolaophonte–Echinolaophonte clade.
Establishment of Pseudechinolaophonte gen. nov. (Fig. 10 /Table 3 : node H)
The Pseudechinolaophonte–Echinolaophonte clade itself splits into two lineages. One lineage, enclosing Echinolaophonte minuta, E. mordoganensis and E. veniliae, can be characterised by 14 autapomorphies (Table
Character 23, cphth dorsally with spinulose, broad projection bearing 2–4 apical teeth [no such projection] (cf. Fig.
Character 24, cphth rectangular, almost squarish [cphth somewhat ovoid, tapering anteriorly, lateral margins convex]: the outgroups Coullia, Hemilaophonte and Xanthilaophonte possess a cphth with rounded, convex lateral margins, with the posterior part being broader than the anterior one. In the Parechinolaophonte–Echinolaophonte clade, however, the cphth underwent different morphological modifications. Echinolaophonte minuta, E. mordoganensis and E. veniliae present a clearly rectangular cphth that is even almost squarish in shape and differs remarkably from the cphth of the remaining 11 species of the Pseudechinolaophonte–Echinolaophonte clade. This clearly different cphth is hypothesised here as a synapomorphic character of the three species.
Characters 25–28, P2–P6-bearing somites dorsally with pair of strong spikes standing closely together [no paired spikes developed] (cf. Fig.
Characters 29, 30, first and second abdominal somite with dorsal sclerotised clasp-like area bearing 2 spikes [these structures not developed] (cf. Fig.
Characters 31, 32, first two abdominal somites with laterally extended epimeres [abdominal somites not extended laterally] (cf. Fig.
Character 33, pseudoperculum developed as sclerotised clasp-like area bearing spikes [no clasp-like area developed] (cf. Fig.
Character 34, A2 endopod surface seta with strongly derived tip [element of regular bipinnate shape]: in E. minuta, E. mordoganensis and E. veniliae, one of the elements arising on the lateral margin in the distal half of the A2 endopod is remarkably transformed and presents a remarkably derived tip that even differs amongst the three species. Nonetheless, whilst all outgroup taxa, as well as Parechinolaophonte tropica gen. et comb. nov. and the remaining species of the Pseudechinolaophonte–Echinolaophonte clade, retain the ancestral bipinnate spine, the development of a strongly deviated element is considered as synapomorphic for the three species.
Character 35, P2 outer basal seta longer than exp-1 and exp-2, biplumose [seta bipinnate, not reaching the distal margin of exp-2]: in E. minuta, E. mordoganensis and E. veniliae, the P2 carries an outer basal seta that is stronger and much more elongated than in all remaining here compared species. Moreover, it is biplumose, with the setules being considerably long. This is regarded as an unambiguous synapomorphy for the three species.
Character 36, female P5 baseoendopod with 2 setae [baseoendopod with at least 3 setae]: in Laophontidae, the female P5 baseoendopod consists of a large, ovoid lobe representing the former endopod with five setae (e.g. Heterolaophonte minuta, cf.
From the argumentation given above and based on the derived characters 23–36, of which the majority is exclusive to E. minuta, E. mordoganensis and E. veniliae, it is here concluded that the three species form a monophyletic taxon within the genus Echinolaophonte as currently composed. Nevertheless, the detected deviations shared by the three species and the recognised remarkable differences between them and the remaining 11 species of the Pseudechinolaophonte–Echinolaophonte clade led to the decision to transfer E. minuta, E. mordoganensis and E. veniliae from the Echinolaophonte–CS group into a distinct, new taxon Pseudechinolaophonte gen. nov. (Fig.
The first branch-off within Pseudechinolaophonte gen. nov. is Ps. mordoganensis gen. et comb. nov. (Fig.
Character 37, cphth dorsal process square, spinulose, with two strong spikes, each outwardly accompanied by two small ones [dorsal process absent or of different shape]: the cephalothoracic dorsal process is different in all three species that are so far assigned to Pseudechinolaophonte gen. nov. Pseudechinolaophonte mordoganensis gen. et comb. nov. presents a squarish sclerotised structure, covered with fine setules and bearing a pair of comparatively stronger spikes that are accompanied on their respective outer sides by two smaller spinules. This is considered as an autapomorphy for the species.
Character 38, A1 female second segment with one subapical outer seta being remarkably elongated, longer that remaining segments together [corresponding seta short]: only Ps. mordoganansis gen. et comb. nov. shows a subapical seta on the second segment of the female A1. It surpasses the apical edge of the last antennular segment; this is regarded as autapomorphic for the species.
Character 39, A2 endopodal surface surface seta comb-like at distal half; not tapering gradually [setal tip of different shape]: as discussed for character 34, the new genus is characterised by a particular lateral spine that ends in a blunt tip; in Ps. mordoganansis gen. et comb. nov. that spine is rounded and finely serrated in its distal half, presenting a somewhat comb-like shape. This is seen here as autapomorphic for Ps. mordoganensis gen. et comb. nov.
Character 40, P5 female baseoendopodal setae not reaching apical margin of exopod [setae at least reaching end of exopod]: whilst in Ps. minuta gen. et comb. nov. and in Ps. veniliae gen. et comb. nov., the setae of the female baseoendopod reach or even surpass the apical edge of the exopod (
The minuta–veniliae clade (Fig. 10 /Table 3 : node J)
The minuta–veniliae clade, on its part, provides six autapomorphies confirming its monophyletic status (Table
Moreover, both species share the loss of the abexopodal seta in the A2 allobasis (Table
Pseudechinolaophonte minuta gen. et comb. nov. (Fig.
Revised compilation of Echinolaophonte
After the above-discussed and phylogenetically justified exclusion of E. tropica, E. minuta, E. mordoganensis and E. veniliae in combination with their transfer to Parechinolaophonte gen. nov. and Pseudechinolaophonte gen. nov., respectively, 11 species remain in Echinolaophonte (Fig.
Character 54, cphth with single spur dorsally on posterior margin [no spur developed] (cf. Figs
The armiger–gladiator clade (Fig. 10 /Table 3 : node N)
Within that genus, two main clades are discernible. A first clade is composed of E. armiger and E. gladiator (armiger–gladiator clade). They share five synapomorphies (Table
Character 55, whole body surface densely covered with fine cuticular structures [body surface smooth]: for two species, their (re-)descriptors explicitly mentioned a coverage of the whole body with “minute denticles” (
Character 56, cphth laterally protruded [no protrusions developed]: In Echinolaophonte, the cphth, particularly its lateral margins, present a remarkable variability (see below, characters 75, 80, 106, 112, 122, 126). Echinolaophonte armiger and E. gladiator share the development of small lateral protrusions (cf.
Character 57, cphth dorsal spur broad, rather short [spur long, slender] (cf. Fig.
Character 58, a slight lateral inflation of the female GDS [female GDS laterally not inflated]: the female GDS of E. armiger and E. gladiator presents a somewhat inflated and confluent aspect, blurring the former frontier between the original urosomites and showing its broadest extension in the area of the fusion. In contrast, in the remaining Echinolaophonte species, the previous distinction between the now fused somites remains clearly discernible by a remarkable lateral constriction in the area of fusion. The lateral inflation, combined with the confluent lateral borders, is seen here as synapomorphic for E. armiger and E. gladiator. A similar shape documented for E. oshoroensis, Xanthilaophonte trispinosa by
Character 59, the development of small spiny processes on the dorsal posterior margin of the pedigerous and first 2 abdominal somites [no cuticular processes developed] (cf. Fig.
Each species can be characterised by four autapomorphies (Table
Character 60, the coverage of the body with small cuticular denticles (cf.
Character 61, the presence of 4 spiny processes standing pairwise together dorsally on the P4-bearing somite;
Character 62, the development of a pair of spiny processes that are fused at their bases on the anterior half of the female GDS, respectively the last thoracic somite of the male (cf.
Character 63, the posterior half of GDS/last thoracic somite of the male and second abdominal somite dorsally with spiny processes standing close together (cf.
Characters 60–63 are exclusively present in E. armiger and, thus, regarded here as unambiguously autapomorphic for that species.
As indicated in Fig.
On the other hand, E. gladiator (Fig.
Character 64, the coverage of the body with fine setules (“hairs”) instead of small denticles;
Character 65, the cephalothoracic lateral protrusions produced into pair of narrow, backwardly directed cuticular jags;
Character 66, the remarkable transformation of the mxp into a strong appendage whose allobasis is swollen on its inner margin and the endopodal claw being massive and curved about 90°;
Character 67, the (female) P3 exp-3 with only two outer spines (cf.
Character 67 is also observable in Xanthilaophonte, Parechinolaophonte tropica gen. et comb. nov. (cf.
The brevispinosa–mirabilis clade (Fig. 10 /Table 3 : node Q)
The remaining clade, here named brevispinosa–mirabilis clade, encloses nine species. It is unambiguously supported by seven autapomorphies (Table
The brevispinosa–mirabilis clade divides again into two clades, namely the brevispinosa–oshoroensis clade (three species) and the villabonae–mirabilis clade (six species). These clades are characterised by four and two autapomorphies, respectively.
The brevispinosa–oshoroensis clade (Fig. 10 /Table 3 : node R)
The species united in the brevispinosa–oshoroensis clade share – besides the supposed convergently developed characters 31 and 32 – four unique characters (Table
Character 75, the lateral cheek-like extension of the cphth [lateral margins of cphth different]; whilst the species pooled here to Pseudechinolaophonte gen. nov. present an almost squarish cphth and that of Parechinolaophonte tropica gen. et comb. nov. displays unique deviations, the cphth of the Echinolaophonte species presents three main variations: (a) the development of lateral protrusions like in E. armiger and E. gladiator and presumably convergent in E. mirabilis and E. musa sp. nov. (Table
Character 76, rostrum elongate, with rounded tip: All three species present a rostrum of a peculiar shape (
Characters 77, 78, the male P3 exopod is powerfully developed (character 77) and bears on its exp-2 a massive, s-shaped outer spine (character 78): the strengthening of the P3 and P4 exopods seem to form part of a sexual dimorphism in Echinolaophonte. In E. brevispinosa, E. horrida and E. oshoroensis, particularly the P3 exopod suffers a remarkable strengthening as compared to the female (
Echinolaophonte brevispinosa (Fig.
Character 79, the emargination of the rostral tip: the rostral tip is rounded regularly in E. horrida and E. oshoroensis, but presents a narrow, but distinct emargination in E. brevispinosa, which is considered as a deviated feature and, thus, as autapomorphic for the latter.
Character 80, the considerable bulging of the cephalothoracic lateral “chubby cheeks”: the lateral “cheeks” present their strongest expression in E. brevispinosa (
The horrida–oshoroensis clade (Fig. 10 /Table 3 : node T)
The monophyly of the horrida–oshoroensis clade is supported by five autapomorphies (Table
Character 81, lateral constriction of the rostral proximal half considerably pronounced;
Character 82, cephalothoracic spur elongated, surpassing posterior margin of cphth;
Character 83, pseudoperculum consisting of 4 tri-denticulated processes (cf. Fig.
Character 84, P1 exopod diminished in length, not reaching half the length of enp-1;
Character 85, male P3 enp-2 apophysis with acute jag basally on inner margin.
In E. brevispinosa, the lateral margins of the rostrum are constricted, but much less than in E. horrida and E. oshoroensis (character 81); the spur on its cphth is small and does not surpass the posterior margin (
Basing on the description of
In contrast, E. oshoroensis (Fig.
Characters 93, 94, secondary loss of the wing-like lateral epimers: As explained in the discussion of features 31 and 32, lateral wing-like epimeres are considered to have arisen convergently on the first two abdominal segments on three occasions: once in Pseudechinolaophonte, once in E. mirabilis and once in the brevispinosa–oshoroensis clade. While E. brevispinosa and E. horrida retained the epimeres, they were secondarily reduced again in E. oshoroensis. This hypothesis is based on the fact that E. horrida and E. oshoroensis are well justifiable as sister-groups on the basis of synapomorphies 81 to 85, whereas neither species shares exclusive derived characters with E. brevispinosa. Only the presence of lateral epimers could be an indication of a closer relationship between E. brevispinosa and E. horrida, which, however, led to the not very plausible assumption that the common derived characters of E. horrida and E. oshoroensis would have to be interpreted as convergences in return. A secondary reduction of the wing-like epimeres in E. oshoroensis, therefore, seems the most plausible and parsimonious explanation.
Character 95, Cphth spur laterally with tufts of long and fine setules: A very similar kind of process has also been observed in Echinolaophonte briani, E. tetracheir (only textual description by
Characters 96–101, presence of lateral cuticular processes from the P2-bearing somite to the second abdominal somite: Echinolaophonte oshoroensis is the only species bearing additional lateral cuticular processes on the body somites, except the pre-anal one and the telson (
Character 102, the male P3 exopod remarkably strengthened: The powerful development of the male P3 exopod (character 78, see above) is further strengthened in E. oshoroensis, having been developed into a massive and broad appendage (
The villabonae–mirabilis clade (Fig. 10 /Table 3 : node W)
The supposed sister group of the brevispinosa–oshoroensis clade is composed of six species, namely E. villabonae, E. briani, E. hystrix, E. tetracheir, E. musa sp. nov. and E. mirabilis. These are united into the villabonae–mirabilis clade and share the following two apomorphic characters related to the shape of the male P3 (Table
Character 103, male P3 endopod 2-segmented [endopod 3-segmented]: The Laophontoidea present a 3-segmented male P3 endopod that is sexually dimorphic, with the enp-2 bearing a well-developed apophysis on its apical outer margin; this is considered as autapomorphy for the Laophontoidea (e.g.
Character 104, male P3 endopod lost sexual dimorphism [male P3 endopod sexually dimorphic]: The loss of a pronounced sexual dimorphism in the male P3 endopod is presumably linked with the reduction of 1 segment. Like character 103, it is a clear deviation as compared with the remaining Echinolaophonte species.
Remarks: It is assumed here that, during the ontogenetic development, the formation of the second segment, which carries the apophysis in the adult male, has been suppressed. However, compared with
The villabonae–mirabilis clade divides into two monophyletic taxa, each characterisable by distinct autapomorphies: the villabonae–briani clade (Table
The villabonae–briani clade (Fig. 10 /Table 3 : node X)
The villabonae–briani clade is characterised by the following derived features provided by E. villabonae, E. briani and E. hystrix:
Character 105, rostrum slightly trapezoid, constricted basally and broadening apically, with rather flat/concave apical margin, distal half smooth: with a basal constriction and a soft distal part, the shape of the rostrum in E. briani (
Character 106, cphth laterally with intricate cuticular ornamentation: E. villabonae, E. briani and E. hystrix share the peculiar cuticular ornamentation along the extended laterodistal margin of the cphth (
Character 107, the female GDS dorsally with cuticular “ring”: Both
Characters 108, 109, posterior half of female GDS and second abdominal somite dorsally with strengthened, spike-bearing cuticular process: such structure is only present in the villabonae–briani clade. Superficially, in dorsal view, it may resemble the respective cuticular structures described for Pseudechinolaophonte gen. nov. (Table
Character 110, the female pseudoperculum consisting of two bi- (or tri-)denticulate processes, laterally accompanied each by two spikes: As already mentioned (cf. discussion of characters 43, 83), the shape of the pseudoperculum is, either intra- and interspecific, highly variable. Otherwise, as discussed above for Pseudechinolaophonte minuta gen. et comb. nov. and Ps. veniliae gen. et comb. nov. (character 43), respectively for Echinolaophonte horrida and E. oshoroensis (character 83), supposed closely-related species can be characterised by an almost identical shape of the pseudoperculum, supporting that close relationship. This applies also to E. villabonae, E. briani and E. hystrix, whose pseudoperculum is almost identical in shape, but differs from that of all remaining species under consideration. Thus, it is seen here as a common deviation.
Echinolaophonte villabonae (Fig.
Echinolaophonte briani (Fig.
Remarks: from the descriptions by
Direct comparison of the species reveals that, in L. steueri, the posterolateral cuticular ornamentation on the cphth is as strongly pronounced as in E. villabonae. Otherwise, L. steueri shares an almost identical cephalothoracic dorsal spur with E. briani, although
The tetracheir–mirabilis clade (Fig. 10 /Table 3 : node AA)
That clade encloses the species Echinolaophonte tetracheir, E. musa sp. nov. and E. mirabilis. Within Echinolaophonte, they share the following four synapomorphies:
Character 115, an elongated rostrum with a bifurcated tip: although the development of an elongated, bifurcated rostrum is also present in other Harpacticoida (e.g. Ancorabolus Norman, 1903 (Ancorabolidae Sars, 1909), Pseudechinopsyllus George, 2006, Pseudopolyascophorus George, 2021 (Cletodinae T. Scott, 1904)), in Laophontidae, only the representatives of the tetracheir–mirabilis clade show that derived development. It is hypothesised here as synapomorphic for the enclosed species.
Character 116, CR at least 3.5 times longer than broad: the caudal rami of the here treated outgroups, as well as of the other here treated taxa are short, reaching mostly twice the length of their broadest width. Instead, the tetracheir–mirabilis clade displays caudal rami that are clearly elongated and slender. This is regarded as autapomorphic for that clade.
Characters 117, 118, outer basal seta of P3 and P4 of composite shape: The development of composite setae in the bases of the P3 and P4 is not common within Laophontidae, as observable, for example, in the here treated outgroups Heterolaophonte minuta, Coullia, Xanthilaophonte and Hemilaophonte janinae. (
The first branch-off within the tetracheir–mirabilis clade is Echinolaophonte tetracheir (Fig.
The musa–mirabilis clade (Fig. 10 /Table 3 : node CC)
The remaining musa–mirabilis clade presents four derived characters (Table
Character 122, cphth laterally with long and slender processes: both species present remarkably long and slender lateral processes on the cphth. Their development is unique not only within Echinolaophonte, but also in Laophontidae and, therefore, considered as synapomorphic for E. musa sp. nov. and E. mirabilis.
Characters 123, 124, cphth equipped with a further anterior and central cuticular process: Besides the dorsal spur that is characteristic for Echinolaophonte, E. musa sp. nov. and E. mirabilis bear two further structures dorsally on the cphth. Behind the rostral area and in the centre of the cphth, two moderate spurs arise (
Character 125, CR at least 5.5 times longer than broad: Echinolaophonte musa sp. nov. and E. mirabilis are the only species within Echinolaophonte, whose caudal rami are remarkably elongated, reaching a length/width ratio of > 5:1. This is regarded as synapomorphic for both species.
The here described Echinolaophonte musa sp. nov. (Fig.
In contrast, a clear-cut characterisation of E. mirabilis (Fig.
However, based on particular re-described body parts provided by
Character 134, the dorsal processes on the P2-bearing somite dorsal processes being long, bearing three long setules basally: no other Echinolaophonte presents such dorsal processes (cf.
Character 135, the dorsal processes on the second abdominal somite are fused basally, with two denticles basally and centrally and with two long setules: As for the previous character, also these processes are unique in Echinolaophonte.
Remarks on previous findings of E. mirabilis in Asia
Amongst the congeners of the Echinolaophonte complex, two Echinolaophonte species were reported from Asia: E. oshoroensis from Japan (
Conclusions
The description of a new laophontid species from Jeju Island (Korea) and the subsequent attempt to allocate it to Echinolaophonte Nicholls, 1941 (Copepoda, Harpacticoida, Laophontidae T. Scott, 1904) revealed that this genus actually constitutes a heterogeneous conglomerate of species that cannot be united by means of clear-cut synapomorphies. Therefore, an exhaustive phylogenetic analysis of Echinolaophonte was undertaken, based on 135 morphological characters. Until the here presented phylogenetic re-evaluation, the genus enclosed 14 species. The phylogenetic analysis resulted, however, in the exclusion of four species from Echinolaophonte: E. tropica Ummerkutty, 1970, was assigned to Parechinolaophonte gen. nov. as Pa. tropica (Ummerkutty, 1970) gen. et comb. nov.; the three Mediterranean species E. minuta Cottarelli & Forniz, 1991, E. mordoganensis Kuru, Sönmez & Karaytug, 2019 and E. venilia Cottarelli, Forniz & Bascherini, 1992 were allocated to Pseudechinolaophonte gen. nov. as Ps. minuta (Cottarelli & Forniz, 1991), gen. et comb. nov., Ps. mordoganensis (Kuru, Sönmez & Karaytug, 2019), gen. et comb. nov. and Ps. venilia (Cottarelli, Forniz & Bascherini, 1992), gen. et comb. nov. Both new genera are characterised by exclusive autapomorphies. Echinolaophonte longantennata Apostolov, 1990 had to be excluded from the phylogenetic revision, due to imprecise and fragmentary description; its systematic position is pending until further material is available for re-examination and re-description, so within the Laophontidae, it is regarded here as species incertae sedis. The remaining nine species are retained in Echinolaophonte, which is now characterised as a monophylum by means of one autapomorphy, i.e. the presence of a dorsal single spur on the posterior margin of the cephalothorax. Moreover, with the description of E. musa sp. nov. from Jeju Island and the elevation of E. armiger f. briani Lang, 1965 to the species level (E. briani Lang, 1965), the number of species assigned to Echinolaophonte increases to 11.
Together with findings of E. oshoroensis in Japan (
The here presented phylogenetic re-evaluation of Echinolaophonte elucidates its former ambiguous phylogenetic status and, thus, might be a helpful step towards the solution of the phylogenetic unclarities within the Laophontidae.
Acknowledgements
The first author would like to express his gratitude to Dr Gritta Veit-Köhler, Senckenberg am Meer, Abt. DZMB, Wilhelmshaven, Germany, for her helpful advice and providing conveniences during his visit to the German Centre for Marine Biodiversity Research (DZMB) and he wishes to express his appreciation to Dr Karin Richter, Untere Naturschutzbehörde, Emden, Germany, for her helpful support in Confocal Laser Scanning Microscopy (CLSM) examination. The authors specially thank Dr Hyun Soo Rho, Korea Institute of Ocean Science and Technology, for collecting samples on Munseom Islet, Jeju Island. The authors are indebted to Dr Seher Kuru, Mersin University, Mersin, Turkey/Senckenberg am Meer, Abt. DZMB, Wilhelmshaven, Germany, for helpful and constructive hints and comments on a former draft of the manuscript. Similarly, three reviewers are thanked for very helpful and constructive comments on the manuscript. This research was supported by the Discovery of Korean Indigenous Species Project, National Institute of Biological Resources. This is publication number 63 that uses data from the Senckenberg am Meer Confocal Laser scanning Microscope Facility (SGN-SaM-cLSM). This research was supported by “Development of Advanced Science and Technology for Marine Environmental Impact Assessment” of Korea Institute of Marine Science & Technology Promotion (KIMST) funded by the Ministry of Oceans and Fisheries (KIMST-20210427).
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