Research Article |
Corresponding author: Rudá Amorim Lucena ( rudalucena15@gmail.com ) Academic editor: Pavel Stoev
© 2022 Rudá Amorim Lucena, Martin Lindsey Christoffersen.
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:
Lucena RA, Lindsey Christoffersen M (2022) Pycnogonida (Arthropoda) from Museu de Ciências Naturais, Rio Grande do Sul, Brazil. Zoosystematics and Evolution 98(2): 305-312. https://doi.org/10.3897/zse.98.83671
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Five species were identified in the studied collection: Colossendeis megalonyx Hoek, 1881, first record for Uruguay, Ascorhynchus corderoi du Bois-Reymond Marcus, 1952 and Pallenopsis candidoi Mello-Leitão, 1949, with extended ranges, Pallenopsis patagonica (Hoek, 1881), a species complex recently analysed with molecular data and Ammothea tetrapoda, recorded previously for Uruguayan waters. Our study clarifies records based on morphology, provides new data on distributions and species ranges and correlates species with ecological conditions.
biological collections, marine invertebrates, Pantopoda, sea spiders, South America, Uruguay
Zoological collections contain a practically inexhaustible amount of information. In Brazil, there are about 26 million deposited specimens (
Class Pycnogonida represents an exclusively marine group of arthropods (
Nonetheless, most Brazilian collections remain little explored (
The material is deposited in the Museum of Natural Science (Museu de Ciências Naturais do Rio Grande do Sul –
Map with the distribution of species present in the Museum of Natural Sciences of Rio Grande do Sul. Legend: black circle, Ascorhynchus corderoi; cross, Colossendeis megalonyx; diamond, Pallenopsis candidoi; triangle, Pallenopsis patagonica; white circle, Ammothea tetrapoda. Abbreviations: ARG, Argentina; BRA, Brazil; BOL, Bolivia; CHI, Chile; PAR, Paraguay; PER, Peru; URY, Uruguay; SC, Santa Catarina.
Identification of the specimens followed
Ascorhynchidae Hoek, 1881
Ascorhynchus Sars, 1877
(FZB.Pyc–001) 31 specimens, Fernando de Noronha, Pernambuco, Brazil, Dec 21, 1978; (FZB.Pyc–007) 5 specimens, Perequê, Nov 2, 1972.
Brazil: São Paulo and Paraíba (
Shallow waters.
The species is recorded herein for the first time for the Archipelago of Fernando de Noronha, expanding its known distribution in north-eastern Brazil. All 31 specimens obtained from Fernando de Noronha were found associated with the epibiont hydrozoan Clytia? Lamouroux, 1812 (FZB.Pyc–001).
The hydrozoans occurred on both the dorsal and ventral surfaces of the trunk (mainly near the dorsal tubercles and the lateral processes), on eggs and ovigers and more densely on the legs (Fig.
Colossendeidae Jarzynsky, 1870
Colossendeis Jarzynsky, 1870
Colossendeis frigida Hodgson, 1902: 63.
Colossendeis rugosa Hodgson, 1907: 64, pl. IX, fig. 3, pl. X, figs 5, 6.
Colossendeis orcadense
–
Colossendeis scoresbii Gordon, 1932: 18–21, figs 5c, 6b, c, 7a, b.
(FZB.Pyc–002) 1 female, South Atlantic, July 8, 1964; (FZB.Pyc–004) 5 females, off Mar del Plata, Argentina (38°22'S, 55°37'W), May 1961, col. L.R. Pontes; (FZB.Pyc–005) 1 female, Uruguay, Mar1961.
Circumpolar. Antarctic, Western South America and up to Buenos Aires (Argentina), South Africa, Madagascar, New Zealand, Eastern South America (
7 to 4900 m in depth.
Colossendeis megalonyx is a very variable species (
Molecular studies confirm that a complex of species exists under the name C. megalonyx. Five species and another seven cryptic species were indicated (
Specimens analysed thus should belong to C. megalonyx, as they were collected in Uruguay (the northernmost record for the species, a full two degrees of latitude north of the record provided by
Pallenopsidae Fry, 1978
Pallenopsis Wilson, 1881
Melloleitanianus candidoi Mello-Leitão, 1955: 122–128, figs 1–4.
Pallenopsis (Pallenopsis) candidoi
–
(FZB.Pyc–003) 2 females, Garopaba, Santa Catarina, Brazil, 24 June 1975.
Up to 430 m.
P. candidoi and P. fluminensis (Krøyer, 1844) are sympatric species, very frequent in depths between 10 and 100 m. These are the commonest species of Pallenopsis along the Brazilian coast. The two species are very similar, varying mainly in the number of setae on the legs (larger and more numerous in P. candidoi) and in the number of articles in the female oviger, in which article 6 is smaller than article 5 and 8 and is less than half as long as article 7 in P. candidoi (article 6 is the same size as article 5 and article 8 is almost the same size as article 7 in P. fluminensis) (
Phoxichilidium patagonicum Hoek, 1881: 84–86, pl. XII, figs 6–9.
Pallenopsis glabra Möbius, 1902: 184–185, taf. XXVII, fig. 1–6.
Pallenopsis hiemalis Hodgson, 1907: 17–20, pl. I, fig. 4, pl. II, fig. 3.
Pallenopsis meridionalis Hodgson, 1914: 158–165.
Pallenopsis moebiusi Pushkin, 1975: 80–83, fig. 4 a–m.
(FZB.Pyc–008) 1 female, St. 4512, 37°38'S, 56°56'W, Argentina, 25 Aug 1977.
15–720 m (
Literature records large morphological variations for this species (
Recent studies, based mainly on molecular data, have indicated the existence of cryptic species under the name P. patagonica, mainly from the Antarctic Region (
The specimen analysed herein comes from northern Argentina, close to the northern range of the species (
Great morphological variation has been reported for several species from polar, temperate and tropical regions, where the genus is quite diverse (
The studied collection further includes one specimen of Ammothea tetrapoda, recorded previously for Uruguayan waters (
A survey of Pycnogonida is needed for southern Brazil. Although the studied collection represents one of the largest for the region, only two specimens of Pallenopsis candidoi from Santa Catarina were identified. The eight known species indicate a biodiversity below that encountered in similar studies for other regions (see
We would like to thank Dr. Ricardo Ott, coordinator of the Arachnid section of the Museum of Natural Science, for providing the material in the collection for study. We are also grateful to Prof. Dr. Miodeli Nogueira Junior for the identification of hydrozoans and to the anonymous referees for their critical reviews, corrections and suggestions regarding the manuscript.