M. martini Stock, 1989

Currently includes five species: M. martini, M. roffensis, M. remyi, M. pavesiae sp. n., M. microphtalma (Amanieu & Salvat, 1963) new comb.

As in Stock (1989) except that the lacinia mobilis of the left mandible is 4 - 5 –dentate. The propodus of the seventh peraeopod carries distinctive tufts of long, slender setae, which are sexually dimorphic. The first antenna with up to 5 articles (versus 3 in Stock). The pleopods are biramous with a basis which is not reduced, but both rami are variously reduced dependant on the total body length of the largest adults of the species. Thus in the smallest species, martini, there is no segmentation in the rami and 1–3 plumose setae and in the largest, microphtalma, there up to 5 segments and 11 plumose setae. The pleopod rami may be sexually dimorphic, as in male M. remyi, and the second antennal flagellum articles are sexually dimorphic in female M. pavesiae sp. n. In addition all species are small, that is to say < 15 mm in total body length and lack epidermal pigment patterns.

Male holotype and 8 females (allotype and paratypes) on loan from Zoological Museum of Amsterdam, Amsterdam, the Netherlands (AMPH. 108.57). Collected by J. Stock on 2 August, 1987 from Gruta das Agulhas in Porto Judeus on the island of Terceira, Azores archipelago.

Known only from the type locality on the island of Terceira.

Not mentioned by Stock (1989).

This is the type species and smallest Macarorchestia. Stock (1989) was equivocal about whether this was a recent troglobiont specialist or trogloxenous form. I concur with the latter view and believe that the adaptations (small body length, body length greater in the female, small eyes, reduced pleopod rami and shortened length of the first 5 peraeopods) indicate that M. martini is a driftwood specialist.

Male holotype (BMNH 1968:64), one female allotype (BMNH 1968:65) and 416 paratypes of all life history stages (BMNH 1968:66). Collected by D.J.Wildish(DJW) in August 1968, 0.2 km upstream from Chatham Ness in Limehouse Reach, Medway estuary, near Rochester, Kent, U.K.

Besides the type locality one other locality in the Medway estuary was found in 1968 with a few specimens in a driftwood log by DJW. The location was ~ 0.6 km upstream from the old Rochester Bridge in Tower Reach on the eastern shore. A few specimens collected by DJW in 1999 from the Swale, in Ferry Reach ~ 0.5 Km northwest of Kingsferry Bridge on the mainland shore.

Absent.

Remarks This is the second smallest Macarorchestia. The type locality was destroyed during reclamation of Frindsbury marsh as an industrial estate.

Two males, 4 females, 1 juvenile (Crust. 25468) ZMB Museum für Naturkunde, Berlin. Collected by A. Schellenberg from a seashore cave at St. Barthelemy, Corisca. A total of 47 individuals (combined sample) of all life history stages, including females with ova, collected by L. Pavesi on 20 January and 15 April 2007 at Principina a Mare, Tyrrhenian Sea, Italy. Sample location co-ordinates: 42°41'18"N, 10°59'53"E. A further sample collected at Principina a Mare by L. Pavesi on 24 April 2011 consisted of 28 individuals of all life history stages, including females with ova. One individual from Corfù Island (Ionian Sea, Greece) collected by L. Pavesi in 2007 (Destructively used in DNA analysis).

Besides the locations found by L. Pavesi for this species, published records include that of Ruffo (1960) in Sardinia and Ruffo (1993) in France, Greece and Italy. Possibly some of these records refer to the species described below.

Absent.

Remarks This is the second largest Macarorchestia. In recent times the type locality has been destroyed by cleaning beaches for the benefit of tourists (L. Pavesi, pers. comm.).

Holotype male of 8.0 mm TBL (NHMUK 2014. 408) and allotype female of 7.5 mm (NHMUK 2014. 409) collected by L. Pavesi on 31 October, 2006 at Lesina, Adriatic Sea, Italy. 13 paratypes collected on the same date (NHMUK 2014. 410 - 419). Paratypes have also been deposited in the Natural History Museum, Verona and Museum at Rome University, Rome, Italy by L. Pavesi.

Lesina, Adriatic Sea, Italy (41°54'11"N, 15°26'50"E).

Other

17 individuals collected by L.Pavesi in April 2006 at Varano, Adriatic Sea, Italy (41°55'12"N, 15°47'29"E).

M. pavesiae sp. n. is distinguished from its close relative, M. remyi, by its smaller size, sexually dimorphic second antennal flagellum articles in adult females and absence of sexual dimorphism in pleopod rami.

Based on male paratypes: total body lengths in the range of 8.0 to 6.7 mm. Figs 1 and 2. The male holotype has similar morphology to male paratypes dissected in preparing the figures.

Head deeper than long (1: 0.7); eyes small, round, less than half the head length. Antenna 1 flagellum 5–articulate with tip just exceeding the junction of peduncle segments 4 and 5 of antenna 2. Antenna 2 short, flagellum 12–articulate, peduncle not incrassate.

Mouthparts. Lower lip with lateral lobes, minute setae on the inner clefts. Left mandible with a 4-dentate lacinia mobilis and large molar process. Right mandible with the tip of the dentate incisor bilobed, 6–dentate lacinia mobilis. Maxilla 1 inner fig narrow with 2 terminal plumose setae, inner margin with long, fine setae; outer fig with a palp, apical robust setae curved and serrated on the inner edge. Maxilla 2 both figs equal in size, inner with a single, plumose seta, with shorter robust setae on the distal edge; outer fig with simple robust setae. Maxilliped inner figs with 3 stout teeth apically, inner, outer and palp distal edges covered with robust setae; palp large and 3–articulated.

Peraeon. Gnathopod 1 weakly subchelate with palmate lobes on propodus and carpus; dactylus as long as propodus lobe; the largest robust setae are present on the posterior edge of the merus. Gnathopod 2 subchelate with propodus and dactylus massively enlarged, dactylus drawn out in a short, blunt tip, its inner surface lacking fine setae. Ventral edge of each coxal fig rounded and with fine robust setae. Peraeopods 3 to 5 short, peraeopods 6 and 7 longer, the latter just longer than uropod 1. Peraeopods 3 and 4 lack a dactylus notch (“pinched unguis”). Peraeopods 6 and 7 not sexually dimorphic in merus and carpus. Six distinctive tufts of long, slender setae originating from the propodus of peraeopod 7 as follows: anterodistal (2 setae), distal (6 setae), anterior side of peraeopod near the first insertion of robust, bifid-tipped setae (4 setae), then on the posterior side of the peraeopod: first insertion of robust, bifid-tipped setae (2 setae), second (4 setae) and third (3 setae). The maximum length of the longest seta from the distal tuft was 144 µm (Fig. 3).

Pleosome. Pleopod basis not reduced and with a pair of hooked coupling spines, robust setae and fine marginal setae absent. All rami are are shorter than the basis. The second pleopod rami have 3 articles each bearing a pair of long, plumose setae: exopod –7, endopod -5.

Urosome. In uropods 1 and 2 the inner and outer rami are of similar length, with 2–4 apical robust setae and 1 or 2 inter-ramal robust setae, basis with 1 or 2 dorsoventral, robust setae distally. Uropod 3 basis longer than the ramus and with 2 large, robust setae dorso-laterally. Smaller robust setae at the ramus tip but lacks inter-ramal robust setae. Telson with a mid-dorsal groove and 6–7 dorso-lateral robust setae on each lobe.

Bbased on non-breeding adult female paratype of 7.3 mm total body length.

Gnathopod 1 without palmate lobes on propodus and carpus. Gnathopod 2 basis slender and with weak robust setae. Palmate lobes present on merus, carpus and propodus, dactylus small (described as “mitten-shaped”gnathopod 2). Pairs of non-ovigerous oostegites on peraeopods 2 to 5. Adult females greater than 7.5 mm body length with no more than 11 antennal flagellum articles (versus up to 13 in males). The 6 tufts of long, simple setae on the propodus of peraeopod 7 in males compares with 2 tufts, of sparser and shorter length setae in females.

Absent.

The name honours Dr. Laura Pavesi who originally discovered and collected the new species during graduate studies at the University of Rome, Italy.

There are three known locations for this species on the shores of the Adriatic Sea and one on Corfú Island, Ionian Sea.

Figure 1. 

M. pavesiae sp. n. Habitus of female allotype total body length (TBL) = 7.5 mm. Mouthparts, telson and uropods from male paratype. Mouthparts, Up3 and telson, scale = 0.1 mm, except Lmnd, Up1 and Up2 = 0.25 mm.

Figure 2. 

M. pavesiae sp. n. habitus of male holotype, TBL = 8.0 mm. Limb parts from male paratype. Scale = 0.25 mm.

Figure 3. 

Peraeopod 7 tip (dactylus and part of propodus) in male (M) and female (F) Macarorchestia. A. M. microphtalma, B. M. roffensis, C. M. remyi, D. M. pavesiae sp. n. Scale = 0.1 mm.

Male holotype (No. 5-1963) and paratypes in the Museum National d’Histoire Naturelle, Paris. Collected in 1962 by Mr. C. Caussanel from Cap Ferret Point near Arcachon on the Atlantic coast of France. Paratypes also in L’Institut de Biologie Marine at Arcachon. Collection by DJW in the type locality on 11^th September 1967 and deposited in the Natural History Museum, London (BMNH 1967 10.6.1–75).

M. microphtalma is distinguished from M. remyi and M. pavesiae sp. n., by:

- Sexually dimorphic tufts of long, slender, simple setae from the propodus of peraeopod P7, with no tuft at anterodistal position and 4 tufts on the posterior side of the propodus in males, versus a tuft at anterodistal position and 3 tufts on the posterior side of the propodus in males of M. remyi and M. pavesiae sp. n. (Fig. 3),

- its larger size, and

- lack of sexual dimorphism in pleopod and second antennal characters. Pleopod sexual dimorphism was discovered by Wildish et al. (2012) in M. remyi where males grew at the same rate as juveniles throughout life, whereas females grew at a slower rate. A2 flagellum article sexual dimorphism was present in M. pavesiae sp. n., where adult females grew at a slower rate than juveniles and males (Wildish et al. 2012).

Known from the

and 3 other locations further south on the French Atlantic coast (Lagardere 1966).

Absent.

Remarks The largest species of Macarorchestia.

Orchestia gammarellus (Pallas, 1766).

Since the erection of Orchestia Leach, 1814 the genus has been uncritically used to include many new species from around the World. In more recent times genera have been split off from Orchestia including: Platorchestia by Bousfield (1982), Palmorchestia by Stock and Martin (1988) and Macarorchestia by Stock (1989). Bousfield (1982) re-defined the range of Orchestia, limiting species to those found in the Atlantic/ Mediterranean region. I have further limited the geographic range of this taxon to the northeast Atlantic, the Mediterranean and Black Seas, but excluding the western Atlantic coastline of North America. The northeast Atlantic islands including: Canary, Madeira and Azore archipelagos are also included in the region. The northerly limit is arbitrarily set at the Arctic Circle (thus including Iceland) and the southern one at the Tropic of Cancer. Circumstantial evidence (Henzler and Ingolffson 2008) supports the presence of Orchestia gammarellus on northwest Atlantic coastlines (as far south as Maine), as a result of recent, post glacial, synanthropic, dispersal from the northeastern shores of the Atlantic.

Taking only Orchestia species which occur within this newly defined geographic range and excluding those outside it, synonyms, and where the taxonomic or ecological status is unclear (inclusive of O. kosswigi Ruffo, 1949–which is figured and described in Ruffo (1993) but its ecological status remains unclear); O. guerni Chevreux, 1889 and O. gambierensis Chevreux, 1908), leaving a total of 13 species (Table 1). The placement of these 13 species in five clearly separate habitats is consistent with a polyphyletic origin for them and that we can expect further generic splitting of Orchestia. In fact Lowry and Fanini (2013) have recently proposed a revision of the genus Orchestia in which all the species belonging to freshwater and terrestrial rain forest leaf litter of the northeast Atlantic islands (columns 3 and 4 in Table 1) were removed to a newly created genus Cryptorchestia. O. kosswigi is also transferred to the new genus and these authors describe a new species referable to Orchestia: O. xylino Lowry & Fanini from the Mediterranean Sea. Recent molecular evidence (Pavesi et al. 2014) does not support the close genetic relationship required by Lowry and Fanini’s proposal between cavimana and the Atlantic islands endemic “Orchestia” listed in column 4 of Table 1. One of these taxa, O. guancha, was shown to be close genetically to O. gammarellus, confirming earlier work by Villacorta et al. (2008). Pavesi et al. (2014 )also show that O. montagui and O. stephenseni are not closely linked genetically to the other species of Orchestia inclusive of the type species O. gammarellus, plus O. mediterranea, O. aestuarensis and O. guancha. With the transfer of O. microphtalma to Macarorchestia herein, this reduces the habitats occupied by “Orchestia” to 4. The genetic findings of Pavesi et al. (2014) suggest the polyphyletic status of Orchestia and a generic level re-alignment like that shown in Table 2. Further genetic and taxonomic work is needed to include all the species listed in Tables 1 and 2.

An interim diagnosis is provided based on the type species, O. gammarellus from the Medway estuary, U.K., as listed in Table 2. This is because of the demonstration of polyphyly (Pavesi et al. 2014) within the older view of the genus Orchestia and because of the resultant taxonomic uncertainty regarding which of the taxa in Table 1 should be included within Orchestia. A diagnosis of the 5 genera listed by letter in Table 2 is delayed because the current COI phylogeny (Pavesi et al. 2014) does not include 6 species of “Orchestia” (indicated by brackets in Table 2). This omission might change the final phylogentic tree obtained with all species listed in Table 2 included.

Adult total body length up to 22 mm; dorsal pigment patterns present; eyes medium in size, approximately one quarter of head length; antenna 1 flagellum just reaching antenna 2 peduncle of article 4; antenna 2 sexually dimorphic, peduncle slightly incrassate in adult males and without ventral fig on peduncle article 3; upper lip without robust setae; mandible left lacinia mobilis 4 dentate; maxilliped palp 3 articulate, article 2 with well developed medial lobe; gnathopod 1 of male subchelate with palm equal to dactyl, carpus and propodus free and with rounded lobes covered with palmate setae; gnathopod 1 of female parachelate, without lobes on carpus and propodus; gnathopod 2 of male strongly subchelate, merus and carpus free, dactylus with blunted tip and is half the length of the enlarged propodus; gnathopod 2 of female, ovigerous oostegite long and wide with many, long, simple, marginal setae, basis expanded anteriorly; peraeopods 3–7 cuspidactylate; peraeopods 5–7 lack slender setae lining the anterior margin of the dactyl; peraeopod 7 sexually dimorphic, adult males with merus and carpus enlarged; distinctive tufts of long simple setae on propodus of peraeopod 7 absent in both sexes; pleon segments 1–3 lacking vertical slits; pleopod rami slightly, or not, reduced; uropods without apical, spade-like robust setae, uropod 1 not sexually dimorphic, peduncle lacking well developed dorsolateral robust setae distally, outer ramus with marginal robust setae, uropod 2 rami equal in length, uropod 3 ramus shorter than peduncle; telson apically notched with 6–8 robust setae per lobe and shorter than uropod 3.

Neotenorchestia kenwildishi gen. sp. n. n.

Monotypic.

As in Orchestia and specifically similar to Orchestia mediterranea A. Costa 1853 except for:

- lack of dorsal pigment patterns (versus dorsal pigment patterns in O. mediterranea as in Wildish, 1987).

- smaller size by neoteny (largest total body length estimated to be 12 to16 mm, versus up to 20 mm in O. mediterranea)

Very similar to Orchestia mediterranea A. Costa 1853 and if characterization is limited to conventional morphological methods this species can easily be misidentified as a juvenile O. mediterranea. The use of relative growth methods and regression fitting predictions as found in Pavesi et al. (2014, see Table 3) are required for definitive identification.

Refers to the origin of the new genus by a form of neoteny and combination of the stem of this word with the genus Orchestia to which it is closely related.

Figure 4. 

Neotenorchestia kenwildishi gen. n., sp. n. Habitus of juvenile paratype, total body length (TBL) = 3.7 mm. All other body parts from immature male holotype, TBL = 7.2 mm. Antennae and pleopod scale = 0.25 mm. Mouthparts, scale = 0.1 mm.

Figure 5. 

Neotenorchestia kenwildishi gen. n., sp. n. Immature male holotype as in Fig. 3, except peraeopod 3 is from a female paratype of TBL = 8.3 mm. Scale = 0.25 mm.

Holotype–immature male of 7.2 mm total body length (NHMUK 2014. 397) and slide preparation from this individual (NHMUK 2014. 397). Nine juvenile paratypes (NHMUK 2014. 398 - 406) and 2 immature females (destructively sampled for temporary slide mounts and mtDNA analysis) removed from a cast-up driftwood log resting at the base of the seawall in the Enteromorpha zone by K.J. Wildish. The driftwood log had been tethered to an old cattle fence on the shore, so it could not float away. It was sampled on 14^th June 2011, 23^rd July 2011 and 13^th August, 2011 from the Swale, near Kingsferry Bridge, U.K.

Approximately 0.5 km west of Kingsferry Bridge, The Swale on the mainland shore in a single rotting driftwood log (~ 3 × 0.5 × 0.5 m) determined to be of Douglas fir by Dr. P. Gasson, Kew (Pavesi et al. 2014). GPS position: 51° 23.97’N, 00° 43.56’E.

Unknown, the largest found was an 8.9 mm TBL immature female. Mature adults predicted by relative growth methods to be 12 to16 mm total body length (Pavesi et al. 2014).

N. kenwildishi sp. n., can readily be distinguished from other driftwood hoppers of the genus Macarorchestia by its medium size eyes (versus small) and unreduced pleopods (rami sub-equal to basis, versus rami shorter than basis).

Based on immature male holotype of 7.2 mm total body length. Figs 4 and 5.

Head deeper than long (1: 0.5); eyes medium/large, round and greater than half the head length. Antenna 1 flagellum 4-articulate. Antenna 2 flagellum 13-articulate. Peduncle not incrassate.

Mouthparts. Upper lip with minute setae on the apical margin. Lower lip deeply cleft and with minute setae on the inner face. Maxilla 1 inner fig slim and with two terminal, plumose setae; inner margin with long fine setae; outer fig with a vestigial palp, apical robust setae curved inwards, some simple and others serrated on the inner edge. Maxilla 2 with inner fig subequal to the outer, inner with a single, plumose seta and fine marginal setae below it; both inner and outer figs with long, simple robust setae which curve inwards. Left mandible with a 4-dentate lacinia mobilis, 6-dentate incisor, strong molar process and setose accessory blades. Maxilliped with 3 strong apical teeth on the inner fig; inner, outer and palp edged with simple, robust setae; palp large and 3-articulated.

Peraeon. Gnathopod 1 weakly subchelate, palmate lobes on propodus and carpus. Gnathopod 2 weakly subchelate with dactylus shorter than the propodus lobe; palmate lobes on propodus, carpus and merus. Peraeopod 3 lacks a dactylus notch (“pinched unguis”), but this is present in an immature female. Peraopod 5 shorter than peraeopods 6 and 7, the latter not sexually dimorphic in the immature male.

Pleosome. Pleopods large and well developed, with 6–7 ramal segments in the endopod, 8 segments in the exopod; rami subequal to basis with paired coupling spines on the inner, distal margin of the basis; 6 simple setae present on the basis of pleopod 1.

Urosome. Uropod 1 rami subequal to peduncle. Peduncle with 2 rows of 2 robust setae. Terminal setae on each ramus consists of 1 large and 1 or 2 smaller robust setae. 3 interamal robust setae on inner and 2 on outer ramus.

Based on immature female of 8.9 mm total body length.

In the absence of sexually mature males and females the only unique female characters found were: absence of palmate lobes on propodus and carpus of gnathopod 1, presence of pinched unguis on peraeopod 3, and presence of small, rudimentary oostegites on coxae of peraeopods 2–5.

The name honours Kenneth J. Wildish who discovered and collected the new taxon in the Swale during the summer of 2011.

Absent.

Known only from the type locality.