Trichorhina cascaisensis, Cifuentes & Bernabé & Da Silva, 2025

Cifuentes, Julio, Bernabé, Iván Escarabajal- & Da Silva, Luís P., 2025, The genus Trichorhina Budde-Lund, 1908 (Crustacea, Isopoda, Platyarthridae) in the Ibero-Balearic region, with descriptions of three new species, Zootaxa 5725 (3), pp. 341-370 : 352-354

Trichorhina cascaisensis sp. nov.

https://zoobank.org/NomenclaturalActs/2626e1cf-e167-4ef3-97f8-4157dbe0f65a

Figs 6 , 12–16

Material examined. Holotype: Male ( MNCN 20.04 /21014 (ex. LPS917a)), Lisboa, Cascais, Manique , 38°43’36.0” N, 9°21’57.0” W, 16/V/2024, leg. L.P. Da Silva. Paratypes: female ( LPS917 b), female ( LPS917 c), female ( MNCN 20.04 /21015 (ex. LPS917d)), same data as holotype .

Etymology. The specific name refers to Cascais, the locality where the specimens used for describing the species were found.

Diagnosis. Dorsal integument with scaly granulations and large fan-shaped scale-setae. Cephalon with large lateral lobes and triangular middle lobe with rounded tip. Posterior corners of all pereonites rounded. Pleon continues pereon contour, with large neopleura. Telson large, wider than long, triangular with obtuse tip.

Description. Maximum length: 3 mm in females, 2.5 mm in males. Lacking pigmentation and ocular apparatus ( Fig. 12A ).

Integumentary characters ( Figs 12A–C , 13A–E ): Dorsal integument with rounded scales and cone-shaped granulations with rounded tips, surrounded by numerous scales, and large scale-setae; granulations arranged in four lines on cephalon, three on pereonites I and II, two on pereonites III to VII, one along posterior margin, all becoming smoother posteriorly; pleonites with line of weak granulations; large fan-like scale-setae interspersed with smaller ones. Noduli laterales successively closer to posterior and lateral edge.

Somatic characters ( Figs 12A–B , 13C–D ): Cephalon not fitting into anterior concavity of pereonite I; frontal line not distinct; vertex convex and continuous with frontal area; large trapezoidal lateral lobes oriented laterally, large triangular middle lobe with rounded tip. Pereonites posterior corner convex. Pleon continues pereon contour, large and falciform neopleura; posterior corner of pleonite V much shorter than posterior edge of uropod protopods. Large triangular telson, wider than long, with obtuse tip.

Appendages ( Figs 12D–E , 14A–E , 15A–C ): Mandibles with 1+1 unequal free penicils, molar penicil dichotomised into three branches, one very small on right mandible. Maxillula inner endite with two penicils, outer endite with eight simple teeth. Maxilla and maxilliped as in Fig. 14D, E . Antennula with three segments, second much shorter; third with four short aesthetascs. Short antennae, barely reaching posterior edge pereonite I; flagellum with two segments, second three times longer than first, with one group of small aesthetascs inserted approximately on last third. Uropod protopods much shorter than telson tip; endopod smaller than exopod.

Sexual characters: Pereopods without sexual differentiation ( Fig. 15D ). Male pleopod I ( Figs. 12F ; 16 A-B) with long and straight endopod with some setae at tip; oval exopod, one and half times wider than long, with rounded internal edge and straight external edge, and some small teeth on posterior edge. Male pleopod II ( Figs. 12G ; 16 C-D) with endopod slightly longer than exopod, ending in thin tip; triangular exopod with long distal part, teeth on external edge and three setae near tip, one very long. Male pleopod exopods III to V as in Fig. 136-G, female exopods as in Fig. 16 H-L.

Ecology. This species was found under rocks in a green space characterized by Mediterranean vegetation, located in a limestone area surrounded by an urban matrix.

Figures

FIGURE 6. Relation between Noduli laterales coordinates d/c (y-axis) and b/c (x-axis) multiplied by 100 for all studied species. A, Trichorhina anophthalma Arcangeli, 1935, JC687; B, Trichorhina cascaisensis sp. nov., LPS917b; C, Trichorhina ornata sp. nov., LPS850; D, Trichorhina silvestrii Arcangeli, 1936, LPS129b; E, Trichorhina solorzanoi sp. nov., MNCN 20.04/21002-5.

FIGURE 12. Trichorhina cascaisensis sp. nov., A–D, female paratype (LPS917b); E–G, male holotype (MNCN 20.04/21014): A, habitus; B, pleon and telson; C, scaly granulation; D, left mandible; E, antenna; F, exopod I; G, exopod II. Scale bars:A = 0.5 mm; B, E–G = 0.1 mm. C–D = 0.01 mm.

FIGURE 13. Trichorhina cascaisensis sp. nov., LPS917b: A, granulation; B, scale-setae; C, cephalon and pereonites I and II; D, telson and uropods; E, noduli laterales b/c and d/c ratios (y axis) and tergite number (x axis). Scale bars: A–B = 0.01 mm; C–D = 0.1 mm.

FIGURE 14. Trichorhina cascaisensis sp. nov., LPS917b: A, left mandible; B, right mandible; C, maxillula; D, maxilla; E, maxilliped. Scale bars: A–E = 0.1 mm.

FIGURE 15. Trichorhina cascaisensis sp. nov., A, C, female paratype (LPS917b); B, D, male holotype (MNCN 20.04/21014): A, antennula; B, antenna; C, uropod; D, pereopod VII. Scale bars: A–D = 0.1 mm.

FIGURE 16. Trichorhina cascaisensis sp. nov., A–G, male holotype (MNCN 20.04/21014); H–L, female paratype (LPS917b): A, endopod I; B, exopod I; C, endopod II; D, exopod II; E, exopod III; F, exopod IV; G, exopod V; H, exopod I; I, exopod II; J: exopod III: K, exopod IV; L, exopod V. Scale bars: A–L: 0.1 mm.