Troglonethes arrabidaensis 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 : 25-28

Troglonethes arrabidaensis Reboleira & Taiti sp. nov.

urn:lsid:zoobank.org:act:78A12550-F7CA-4892-9E90-7F85446423D3

Figs 16 A–G, 17A–D

Diagnosis

A species of Troglonethes characterised by the antenna having three flagellar articles, the male pereopod 7 carpus enlarged in the basal part, the pleopod 1 exopod triangular, as wide as long, and the male pleopod 2 endopod with the distal article bearing an apical hook-like process.

Etymology

The new species is named after the type locality, the Arrábida karst massif.

Material examined

Holotype

PORTUGAL: ♂, Gruta do Frade , Arrábida Massif, 16 Aug. 2013 ( MZUF).

Paratypes

PORTUGAL: 3 ♂♂, 13 ♀♀, same data as holotype ( MZUF, SR and ZMUC).

Description

Maximum size: ♂ and ♀ 2.7× 0.8 mm. Body colourless and elongated ( Fig. 16A ). Dorsum of cephalon and pereonites with two rows and one row of large granules, respectively; each granule with a scale-seta ( Fig. 16B ); pleon and telson smooth. Cephalon ( Fig. 16 C–D) with short, quadrangular frontal lateral lobes. Eyes absent. Pereonites 1–3 with rounded posterior corners; pereonites 4–7 with epimera pointing backwards ( Fig. 16A ). Pleon ( Fig. 16A, E ) slightly narrower than pereon; pleonites 3–5 with small epimera and very short posterior points. Telson ( Fig. 16E ) about twice as wide as long, with distal part trapezoidal, with concave sides and broadly rounded apex. Antennula ( Fig. 16F ) with three articles; third article with three long aesthetascs at apex. Antenna ( Fig. 16G ) with fourth and fifth article of peduncle with distinct tubercles bearing scale-setae; fifth article slightly shorter than flagellum; flagellum with

three articles, with two long aesthetascs on second article. Buccal pieces as in previous species. Uropod ( Fig. 16E ) with exopod slightly longer than endopod, exopod and endopod inserted at same level.

MALE. Pereopod 1 ( Fig. 17A ) with no particular modifications. Pereopod 7 ( Fig. 17B ) ischium with straight sternal margin, carpus enlarged in basal part. Genital papilla ( Fig. 17C ) fusiform, with rounded apex, much longer than pleopod 1. Pleopod 1 ( Fig. 17C ) exopod triangular, as wide as long, with broadly rounded apex; endopod with basal article elongated, shorter than exopod, with sinuous outer margin, distal article flagelliform. Pleopod 2 ( Fig. 17D ) exopod triangular, with broadly rounded apex with few short setae; endopod biarticulated, basal article more than twice as long as distal one, with parallel sides, distal article with hook-like process at apex.

Remarks

The new species is very similar to Troglonethes aurouxi in the dorsal granulation and shape of the male pleopod 2. It differs in having the antennal flagellum with three, instead of four, articles, and a wider male pleopod 1 exopod. It is readily distinguishable from T. olissipoensis Reboleira & Taiti sp. nov. in the larger and less numerous dorsal granules, the enlarged basal part of the male pereopod 7 carpus, the male pleopod 1 endopod with the basal article shorter than the exopod, and the distal article of the male pleopod 2 endopod lacking the hook-like process at the base.

Ecological notes

This species was only found in the Gruta do Frade in the Arrábida Massif. The cave entrance is by the seashore and there are several anchialine lakes inside, influenced by the sea tides. It is the first record of troglobiotic terrestrial isopods in Arrábida.

Figures

Fig. 16. Troglonethes arrabidaensis Reboleira & Taiti sp. nov. from Gruta do Frade, Arrábida. — Paratype, ♀. A. Adult specimen in dorsal view. B. Dorsal scale-seta. C. Cephalon in frontal view. D. Cephalon in dorsal view. E. Pleonites 4, 5, telson and left uropod. — Paratype, ♂. F. Antennula. G. Antenna.

Fig. 17. Troglonethes arrabidaensis Reboleira & Taiti sp. nov. from Gruta do Frade, Arrábida, paratype, ♂. A. Pereopod 1. B. Pereopod 7. C. Genital papilla and pleopod 1. D. Pleopod 2.