Diploexochus obscurus, B & B & B, 2023
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publication ID |
https://doi.org/ 10.1590/2358-2936e2023008 |
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publication LSID |
lsid:zoobank.org:pub:88BC9632-9146-4B75-B62F-59480ABB3E24 |
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DOI |
https://doi.org/10.5281/zenodo.10951477 |
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persistent identifier |
https://treatment.plazi.org/id/03F6DD4B-FFDC-1314-FE8C-FC6CFADFF96E |
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treatment provided by |
Felipe |
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scientific name |
Diploexochus obscurus |
| status |
sp. nov. |
Diploexochus obscurus View in CoL sp. nov.
( Figs. 7 – 10 View Figure 7 View Figure 8 View Figure 9 View Figure 10 )
Zoobank: urn:lsid:zoobank.org:act:E2B21901-1FE9-4731-B8B0-B00C3FA56987
Typematerial. Holotype: male ( ISLA77539 , part in slide), Brazil, Bahia State, municipality of Carinhanha , Água Escura I cave (-13.817694º -43.950366º), 17 September 2021, G.M. Cardoso and R.L. Ferreira coll. Paratypes: 3 females (1 in slide) ( ISLA 77540 ), same data as holotype .
Diagnosis. Dorsal surface covered with acute and rectangular tubercles; pereonites2–7 with11 tubercles in 2 rows; pleonite 3 with 4 tubercles, pleonites 4, 5 and telson with 2 paramedian tubercles; uropod exopod inserted medially, endopod around threefold exopod length.
Description. Body length: ♂ 7.5 mm, ♀ 6 mm. Body gray with depigmented spots; antenna 5 th article and flagellum yellowish ( Fig. 7A View Figure 7 ). Endoantennal conglobation. Dorsal surface covered with acute and rectangular tubercles disposed as follows ( Fig. 8A,B View Figure 8 ): cephalon with 12 tubercles in 3 rows; pereonite 1 with 21 tubercles in 3 rows; pereonite 2 with 13 tubercles in 2 rows; pereonites 3–7 with 11 tubercles in 2 rows; pleonite 3 with 4 tubercles, pleonites 4 and 5 with 2 paramedian tubercles, telson with 2 tubercles. Dorsal surface with short semi-circular scale-setae ( Fig. 7C View Figure 7 ). Cephalon ( Figs. 7B View Figure 7 , 8C, D View Figure 8 ) with frontal shield prominent, protruding above vertex, distal margin straight; eye with about16 ommatidia.Pereonites with epimera flattened and directed backwards; pereonite 1 strongly grooved on lateral margin, inner lobe of schisma rounded ( Fig. 8C, E View Figure 8 ); pereonite 2 with triangular ventral lobe; pereonites 5–7 with oblique ventral ridge. Pleonites 3–5 ( Fig.8F View Figure 8 ) with epimera well developed, quadrangular with round distal margin, slightly directed outwards. Telson hourglass-shaped, base wider than distal part, distal margin straight. Antennula ( Fig. 7D View Figure 7 ) of 3 articles, proximal and distal articles subequal in length, distal article with 2 lateral and 5 apical aesthetascs. Antenna ( Fig.8G View Figure 8 ) short, not surpassing distal margin of pereonite 1; flagellum of 2 articles, distal article about fourfold longer than first, with 1 row of aesthetascs. Mandible ( Fig. 8H, I View Figure 8 ) molar penicil simple; left mandible with 2 + 1 and right mandible with 1 + 1 free penicils. Maxillula ( Fig. 8J View Figure 8 ) outer branch with 4 + 5 simple teeth. Maxilla ( Fig. 8K View Figure 8 ) bilobate, outer lobe twice wider than inner lobe, covered with thin setae. Maxilliped ( Fig. 8L View Figure 8 ) endite with medial seta surpassing distal margin, distal margin slightly rounded with 2 short triangular setae; palp with 2 setae on basal article. Pereopod 1 with longitudinal antennal grooming brush, dactylus inner claw not surpassing outer claw, dactylar organ and ungual seta simple, with longitudinal scale-field ( Fig. 9A View Figure 9 ). Pleopods 1–5 with monospiracular lungs. Uropod ( Fig. 7D View Figure 7 ) protopod flattened, distal part subrectangular, exopod short inserted medially, endopod stout, short, not reaching the insertion of exopod, around threefold exopod length.
Male: pereopods 1 and 7 ( Fig. 9A, B View Figure 9 ) with no particular modifications. Genital papilla with triangular ventral shield, papilla slightly surpassing ventral shield with apical orifices ( Fig.9C View Figure 9 ). Pleopod 1 ( Fig. 9C View Figure 9 ) exopod small, triangular, wider than long; endopod about 4 times longer than exopod, distal part straight. Pleopod 2 ( Fig. 9D View Figure 9 ) exopod triangular, outer margin strongly concave bearing setae;endopod longer than exopod. Pleopods 3 and 4 exopods as in Fig. 9E, F View Figure 9 .
Etymology. The specific epithet “obscurus ” refers to the cave where the species was collected, Água Escura (that in Portuguese means dark water).
Habitat and ecological remarks. Specimens of D. obscurus sp. nov. were found in a limestone cave (Água Escura I cave) located in the region of “Serra do Ramalho”, northeastern Brazil. This area has hundreds of caves and several cave-restricted species (e.g., Baptista and Giupponi, 2002; Kamimura and Ferreira, 2018; Hellmann et al., 2020). Although many other caves in the area were also inventoried, specimens of D. obscurus sp. nov. were only found in this cave. Although this cave is peripheral to the main subterranean drainage in the area, it can be considered part of the Água Clara cave system, which comprises the richest hotspot of subterranean biodiversity in South America ( Souza-Silva et al., 2021). The Água Escura I cave presents a single entrance, located at the base of a limestone outcrop ( Fig. 10A View Figure 10 ). The cave presents two main conduits (one intercepting the other), which were extremely dry during the samplings ( Fig. 10C View Figure 10 ). However, the cave conduits are located at a lower level when compared to the surface, so that the water from f loods can enter the cave, submerging part of its chambers during strong rains ( Fig. 10B View Figure 10 ). According to Köppen’s climate classification system, the local climate is “Aw”, with dry winter and an average annual rainfall of 640 mm 3 ( Alvares et al., 2013). Only four specimens of D. obscurus sp.nov. were found in the cave ( Fig. 10D, E View Figure 10 ), all sheltered under big rocks, in which microhabitats still retained some moist content on the subjacent f loor ( Fig. 10C View Figure 10 ). The cave surroundings are severely impacted ( Fig. 10A View Figure 10 ), mainly by deforestation and fires, although cattle and goat breeding were also observed. As mentioned for D. spinatus sp. nov., the cave is likely being used by D. obscurus sp. nov. as a refuge, considering the highly impacted area surrounding the cave.
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