Pectenoniscus morrensis, Ferreira, 2020
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publication ID |
https://doi.org/10.1590/2358-2936e2020039 |
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persistent identifier |
https://treatment.plazi.org/id/875F1C5E-FFC3-FFD5-FC41-F8C9FE0FF8E7 |
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treatment provided by |
Felipe |
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scientific name |
Pectenoniscus morrensis |
| status |
sp. nov. |
Pectenoniscus morrensis View in CoL n. sp.
( Figs. 17–20 View Figure 17 View Figure 18 View Figure 19 View Figure 20 , 21 View Figure 21 , 22F View Figure 22 )
Zoobank: urn:lsid:zoobank.org:act:D36398C8-2515-45C7-A1A7-D39CB703C8CF
Type material. Holotype: male (ISLA 77534), Brazil, Bahia, Morro do Chapéu , Gruta dos Brejões cave (-11.007225° -41.435169°), 23 January 2012, leg. R. L. Ferreira . Paratypes: 7 males, 7 females ( ISLA 77535), same data as holotype .
Diagnosis. Male pleopod 1 exopod triangular with lateral margin straight, round apex; endopod more than twice longer than exopod; male pleopod 2 exopod subtriangular, and endopod apex twisted with lateral projection directed outward.
Description. Maximum length: male, 2 mm. Colorless, eyes absent ( Figs. 17A View Figure 17 , 19A View Figure 19 , 20F View Figure 20 ). Dorsal scale-setae tricorn-shaped ( Fig. 19A, B View Figure 19 ). Dorsal granulations in two rows on pereonites 1 to 7, smooth pleon ( Fig. 19B, C View Figure 19 ). Cephalon with round antennal lobes; supra-antennal line bent in middle ( Fig. 19A View Figure 19 ). Pereonite 1 with margin projected forward, not surpassing median portion of cephalon; pereonites 4–7 posterior margin progressively more concave; pleonites 3–5 epimera posterior points slightly developed; pleon narrower than pereon ( Figs. 17A View Figure 17 , 19C View Figure 19 ). Pleotelson with concave margin and round apex ( Fig.17B View Figure 17 ). Antennula with three articles, distal article with six aesthetascs ( Fig. 17C View Figure 17 ). Antenna surpasses pereonite 2 when extended backwards, fifth article of peduncle shorter than f lagellum, with one seta longer than the second flagellum article; flagellum with three articles ( Fig. 17D View Figure 17 ). Left mandible with two penicils ( Fig. 17E View Figure 17 ); right mandible with one penicil, lacinia mobilis leaf-shaped ( Fig.17F View Figure 17 ). Maxillula outer branch with 4+5 teeth, apically entire, and one plumose seta; inner branch with three penicils ( Fig. 17G View Figure 17 ). Maxilla with bilobate apex, inner lobe wider than outer lobe with several setae on distal margin ( Fig. 17H View Figure 17 ). Maxilliped basis enlarged on distal portion; palp with two setae; endite triangular, apex with one penicil and two spines ( Fig.17I View Figure 17 ). Pereopod 1 antennal grooming brush composed of serrated scale setae on propodus and on sternal margin of carpus ( Fig. 18A View Figure 18 ); dactylar seta bifid with thin setule. Uropod protopod rectangular, longer than distal margin of pleotelson; exopod longer than endopod, inserted distally ( Fig. 17B View Figure 17 ).
Male: Pereopods 6 and 7 propodus with tufts of setae on tergal margin; water conducting system; pereopod 7 ischium with convex sternal margin ( Fig. 18B, C View Figure 18 ). Genital papilla ( Fig. 18D View Figure 18 ) with medial portion slightly enlarged with narrow apex. Pleopod 1 ( Fig. 18D View Figure 18 ) protopod rectangular, two times wider than long; exopod triangular, lateral margin straight, round apex; endopod more than twice longer than exopod. Pleopod 2 ( Fig. 18E View Figure 18 ) protopod rectangular; exopod subtriangular, almost twice wider than long; endopod with distal article three times longer than proximal article, apex twisted with lateral projection directed outward. Pleopod 3–5 exopods ( Fig.18F–H View Figure 18 ) subquadrangular, bearing five, four and three setae on outer margin, respectively.
Etymology. The specific epithet “ morrensis ” refers to the municipality of Morro do Chapéu, where the new species was collected.
Remarks. Pectenoniscus morrensis n. sp. differs from P. angulatus and P. liliae by the dorsal granulation pattern (two rows in all the pereonites versus three rows in the first pereonite and two in P. angulatus and P. liliae ), the number of aesthetascs on antennula (6 versus 8 in P.angulatus and 9 in P. liliae ), the shape of male pleopod 2 exopod (subtriangular versus rectangular in P. angulatus and ovoid in P. liliae ) and the orientation of endopod (twisted versus straight in P. angulatus and P. liliae ). Pectenoniscus morrensis n. sp. is similar to P. santanensis n. sp. in the number of aesthetascs on antennula, by the shape of male pleopod 1 exopod triangular with lateral margin straight and round apex; and by the shape of male pleopod 2 exopod subtriangular, however, it differs by the shape of male pleopod 2 endopod.
Habitat and ecological remarks. Specimens of P. morrensis n. sp. were found in Gruta dos Brejões cave, located in the municipality of Morro do Chapéu (state of Bahia) ( Fig. 21 View Figure 21 ). The cave presents an impressive entrance of 106 meters high ( Fig. 20C View Figure 20 ) followed by a chamber with similar dimensions. The cave extends 6,570 meters, but it was longer in the past, trespassing a massive limestone outcrop ( Figs. 20C, D View Figure 20 , 21F View Figure 21 ). During the karst evolution in the area most of its original conduit collapsed, creating a canyon ( Fig. 20D View Figure 20 ). In fact, the cave presents two conduits (Gruta I e II) laterally connected in some areas. The upper level is predominantly dry and presents huge skylights and impressive speleothems ( Fig. 20E View Figure 20 ). On the other hand, the lower level is moist due to the presence of the Jacaré river, which arises among collapsed blocks (around 750 meters from the main entrance) and covers a considerable extension of the lower level. There are ponds connected to the river in some areas of the lower level in which a thin layer of calcite is deposited on the water surface. When the water level drops, such pieces of calcite are deposited on the muddy sediment of the riverbanks. Individuals of P. morrensis n. sp. were found under those calcite fragments walking on the substrate ( Fig. 20F View Figure 20 ). The organic resources observed in this area were a few small fragments of vegetal debris, transported to the cave by the river. This river shelters the unique troglobitic Porifera from Brazil (the sponge Racekiela cavernicola Volkmer-Ribeiro, Bichuette and De Sousa Machado, 2010 ), which is extremely abundant on the riverbed, presenting hundreds of individuals. Another troglobitic species inhabiting the cave is the spider Ariadna aurea Giroti and Brescovit, 2018 . The external landscape surrounding the cave is altered. Although the upper part of the limestone outcrop is well preserved in some areas (due to the difficulties of access), the Jacaré river valley is severely altered especially because it constitutes the only water source in the region. There are many crops grown in the valley ( Fig. 22F View Figure 22 ).
| R |
Departamento de Geologia, Universidad de Chile |
No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.