Metatrichoniscoides salirensis Reboleira & Taiti, 2015

Reboleira, Ana Sofia P. S., Gonçalves, Fernando, Oromí, Pedro & Taiti, Stefano, 2015, The cavernicolous Oniscidea (Crustacea: Isopoda) of Portugal, European Journal of Taxonomy 161, pp. 1-61 : 17-21

Metatrichoniscoides salirensis Reboleira & Taiti sp. nov.

urn:lsid:zoobank.org:act:7E09D1C5-19F8-44DF-A1AE-B2D741C411AE

Figs 10 A–G, 11A–E, 12A–E

Diagnosis

A blind and colourless Metatrichoniscoides characterised by the male pleopod 1 exopod having two long distal setae subequal in length, and the male pleopod 2 endopod having a thickset distal article, ending in a thinner sinuous part with a beak-like small lobe medially directed.

Etymology

The new species is named after Gruta de Salir, the cave where the specimens were collected, in the municipality of Caldas da Rainha.

Material examined

Holotype

PORTUGAL: ♂, Gruta de Salir, Salir do Porto, Caldas da Rainha , 26 Dec. 2012 ( MZUF).

Paratypes

PORTUGAL: 1 ♂, 2 ♀♀, same data as holotype ( MZUF); 1 ♂, 2 ♀♀, same data as holotype (SR).

Description

Maximum size: ♂ and ♀ 2.2 × 0.8 mm. Body colourless, elongated and slightly convex ( Fig. 10A ). Cephalon and pereon with granulated dorsal surface; granules on pereonites arranged in double rows; each granule bearing a triangular scale-seta ( Fig. 10B ). Cephalon ( Fig. 10 C–D) with no frontal lateral lobes. Eyes absent. Pereonites 1–4 ( Fig. 10A ) with rounded posterior corners; pereonites 5–7 ( Fig. 10A ) with epimera directed backwards. Pleon ( Fig. 10A,E ) narrower than pereon; pleonites 3–5 with small epimera and short posterior points. Telson ( Fig. 10E ) twice as wide as long, with distal part trapezoidal with concave sides. Antennula ( Fig. 10F ) with three articles; third article distinctly longer than first and second and bearing four long aesthetascs at apex. Antenna ( Fig. 10G ) with fifth article of peduncle slightly shorter than flagellum; flagellum with three articles, with two aesthetascs on second article. Mandibles ( Fig. 11 A–B) with two penicils on the right and three on the left; molar process without penicils. Maxillula ( Fig. 11C ) with inner branch bearing three short penicils at apex; outer branch with 11 teeth and two thin stems. Maxilla ( Fig. 11D ) apically bilobed, with outer lobe shorter than inner one; inner lobe with some long, stout setae near medial margin. Maxilliped ( Fig. 11E ) endite triangular, ending with triangular point and subapical penicil; palp distally rounded, with long setae, and basal article with two short compound setae. Uropod ( Fig. 10E ) with exopod slightly longer than endopod; exopod with several long, pointed setae and endopod with long seta at apex.

MALE. Pereopod 1 ( Fig. 12A ) and pereopod 7 ( Fig. 12B ) with no peculiar modifications. Genital papilla ( Fig. 12C ) fusiform, with rounded apex. Pleopod 1 ( Fig. 12D ) exopod as long as wide, with broadly rounded apical margin bearing two long setae of equal length; endopod with basal article triangular, batonlike distal article inserted on medial margin of basal article. Pleopod 2 ( Fig. 12E ) exopod trapezoidal, with short seta at apex; endopod biarticulated, distal article thickset, ending in thinner sinuous part with beak-like small lobe medially directed.

Remarks

Until now the genus Metatrichoniscoides included only four species ( Schmalfuss 2003): M. leydigii (Weber, 1880) from western France, Belgium, the Netherlands, western Germany and greenhouses in the Czech Republic, Sweden and Finland; M. nemausiensis Vandel, 1942 and M. fouresi Vandel, 1950 from France; and M. celticus Oliver & Trew, 1981 from Wales ( Vandel 1942; Oliver & Trew 1981). Metatrichoniscoides salirensis Reboleira & Taiti sp. nov. is readily distinguished from all the other species in the genus by the male pleopod 1 exopod bearing two long setae and the peculiar shape of the male pleopod 2 endopod. This represents the first record of the genus for Portugal and the Iberian Peninsula.

Ecological notes

Gruta de Salir is a peculiar, beautiful cave located near the sea, with a genesis related to previous sea levels, evidenced by the presence of marine sand in the lowest parts. This is the first troglobiotic species known from this cave and this karst area.

Figures

Fig. 10. Metatrichoniscoides salirensis Reboleira & Taiti sp. nov. from Gruta de Salir, Caldas da Rainha typhonic valley. — Paratype, ♀. A. Adult specimen in dorsal view. B. Dorsal scale-seta. C. Cephalon in frontal view. D. Cephalon in dorsal view. — Paratype, ♂. E. Pleonites 4, 5, telson and right uropod. F. Antennula. G. Antenna.

Fig. 11. Metatrichoniscoides salirensis Reboleira & Taiti sp. nov. from Gruta de Salir, Caldas da Rainha, paratype, ♂. A. Right mandible. B. Left mandible. C. Maxillula. D. Maxilla. E. Maxilliped.

Fig. 12. Metatrichoniscoides salirensis Reboleira & Taiti sp. nov. from Gruta de Salir, Caldas da Rainha, paratype, ♂. A. Pereopod 1. B. Pereopod 7. C. Genital papilla. D. Pleopod 1. E. Pleopod 2.