Pectenoniscus iuiuensis, Ferreira, 2020

Pectenoniscus iuiuensis View in CoL n. sp.

( Figs. 8–10 View Figure 8 View Figure 9 View Figure 10 , 21 View Figure 21 , 22C View Figure 22 )

Zoobank: urn:lsid:zoobank.org:act:2BF7FDE6-4BF8-4092-A726-CABF8E86E378

Type material. Holotype: male (ISLA 77530), Brazil, Bahia, Iuiu, Baixa da Fortuna cave (-14.547433° -43.654089°), 21 November 2016, leg. R. L. Ferreira . Paratypes: 2 males, 3 females ( ISLA 77531), same data as holotype .

Diagnosis. Pereonites epimera well developed with pereonite 1 anterior margin projected forward; male pleopod 1 exopod triangular with lateral margin sinuous; male pleopod 2 exopod subrectangular, and male pleopod 2 endopod twisted with wrench-like shape and distal projection directed outward.

Description. Maximum length: male, 3 mm. Colorless, eyes absent ( Figs. 8A View Figure 8 , 10D View Figure 10 ). Dorsal scale-setae tricorn-shaped ( Fig. 8B View Figure 8 ). Dorsal granulations disposed in three rows on pereonite 1 and in two on pereonites 2–7, smooth pleon ( Fig. 8A, C View Figure 8 ). Cephalon with round antennal lobes; supra-antennal line bent in middle ( Fig. 8B View Figure 8 ). Pereonites epimera well developed; pereonite 1 with anterior margin projected forward, reaching median portion of cephalon; pereonites 3–7 posterior margin progressively more concave, pereonite 7 distal margin reaches pleonite 3; pleonites 3–5 epimera posterior point developed; pleon narrower than pereon ( Fig. 8A View Figure 8 ). Pleotelson with concave margin and round apex ( Fig. 8C View Figure 8 ). Antennula with three articles, distal article with ten aesthetascs ( Fig. 8D View Figure 8 ). Antenna surpasses pereonite 1 when extended backward, fifth article of peduncle shorter than f lagellum, with one seta longer than first flagellum article; flagellum with three articles ( Fig. 8E View Figure 8 ). Left mandible with two penicils ( Fig. 8F View Figure 8 ); right mandible with one penicil, lacinia mobilis leaf-shaped ( Fig. 8G View Figure 8 ). Maxillula outer branch with 4+4 teeth, apically entire, and one plumose stalk; inner branch with three penicils ( Fig. 8H View Figure 8 ). Maxilla with bilobate apex, inner lobe wider than outer lobe with several setae on distal margin ( Fig. 8I View Figure 8 ). Maxilliped basis enlarged on distal portion; palp with two setae; endite triangular, apex with two spines and one penicil ( Fig. 8J View Figure 8 ). Pereopod 1 antennal grooming brush composed of serrated scale setae on propodus and on sternal margin of carpus ( Fig. 9A View Figure 9 ); dactylar seta bifid with thin setule. Uropod protopod rectangular, longer than distal margin of pleotelson; exopod longer than endopod, inserted distally ( Fig. 8C View Figure 8 ).

Male: Pereopods 6 and 7 ( Fig. 9B, C View Figure 9 ) propodus with tufts of setae on tergal margin; with water conducting system; pereopod 7 ischium with convex sternal margin. Genital papilla ( Fig. 9D View Figure 9 ) medial part enlarged, apex narrow. Pleopod 1 ( Fig. 9D View Figure 9 ) protopod rectangular; exopod triangular, long, with 2/3 of endopod length, lateral margin sinuous; endopod distal article twice longer than basal article. Pleopod 2 ( Fig. 9E View Figure 9 ) protopod rectangular; exopod subrectangular, twice wider than long; endopod with distal article two times longer than proximal article, wrench-like shape, round apex with bifid distal projection directed outward. Pleopod 3–5 exopods ( Fig. 9F–H View Figure 9 ) subquadrangular, bearing four-five setae on outer margin.

Etymology. The specific epithet iuiuensis refers to the mountain range where the new species was collected, Serra de Iuiú.

Remarks. Pectenoniscus iuiuensis n. sp. differs from P. angulatus by the number of aesthetascs on antennula (10 versus 8 in P. angulatus ), the number of articles in the antenna flagellum (3 versus 5 in P. angulatus ), the shape of male pleopod 1 exopod (both with round apex, although lateral margin is sinuous versus straight in P. angulatus ) and the shape of male pleopod 2 endopod. From P. liliae , P. iuiuensis n. sp. differs by the number of aesthetascs on antennula (10 versus 9 in P. liliae ), the shape of male pleopod 1 exopod (lateral margin sinuous versus straight in P. liliae ), the shape of male pleopod 2 exopod (subrectangular versus ovoid in P. liliae ) and the shape of pleopod 2 endopod. From P. montalvaniensis n. sp. and P.juveniliensis n. sp., P. iuiuensis n. sp. differs by the well-developed epimera; by the number of aesthetascs on antennula (versus 8 and 9, respectively); the shape of male pleopod 1 exopod triangular with sinuous lateral margin (versus straight, in P. montalvaniensis and P. juveniliensis ); and by the subrectangular male pleopod 2 (subrectangular versus trapezoid and triangular, respectively).

Habitat and ecological remarks. Specimens of P. iuiuensis n. sp. were found in Baixa da Fortuna cave (municipality of Iuiú, state of Bahia), which comprises a relatively small limestone cavity ( Fig. 21 View Figure 21 ). The cave is surrounded by vertical outcrops ( Fig. 10A, B View Figure 10 ), requiring one to climb in order to reach the entrance ( Fig.10C View Figure 10 ). The single cave conduit presents a small autogenic drainage that arises in the innermost part of the cave (upstream) and flows toward the entrance, then sinking on the opposite side of the conduit (downstream) after the entrance. Hence, the cave entrance is laterally located in relation to this drainage. Individuals of P. iuiuensis n. sp. were observed walking on the cave sediments, especially close to the stream, always in the deeper portions of the cave. Few specimens were found despite efforts to make a thorough search in the cave due to its small dimensions. Another troglobitic species inhabiting this cave is the bochicid pseudoscorpion Spelaeobochica iuiu ( Ratton et al., 2012) . The external area surrounding the cave presents a well-preserved forest ( Figs.10A View Figure 10 , 22C View Figure 22 ), although pastures are observed a few kilometers from the cave (about 2 to 3 Km). No signs of human visitation were observed, probably due to the hard access to the cave; in this sense the cave is preserved.