Indobathynella socrates, Shaik, 2019

Shaik, Shabuddin, 2019, A New Indobathynella Species from an Indian Cave. The First Cavernicolous Bathynellidae (Syncarida: Bathynellacea) from South-eastern India, Zootaxa 4565 (3), pp. 345-360 : 346-354

publication ID	https://doi.org/ 10.11646/zootaxa.4565.3.2
publication LSID	lsid:zoobank.org:pub:C183975C-5874-495A-BC93-CEBC680C9B57
DOI	https://doi.org/10.5281/zenodo.5923843
persistent identifier	https://treatment.plazi.org/id/03E987F2-FFB5-9D42-FF57-6085FAF6FCC1
treatment provided by	Plazi
scientific name	Indobathynella socrates
status	sp. nov.

Treatment

Indobathynella socrates n. sp.

( Figs. 1–7 View FIGURE 1 View FIGURE 2 View FIGURE 3 View FIGURE 4 View FIGURE 5 View FIGURE 6 View FIGURE 7 )

Diagnosis. Body integument thin. Antennule 7-segmented; ultimate segment with2 equal aesthetascs. Antenna 4- segmented; exopod without subapical seta. Mandibular gnathobase fused with basal segment of palp and represented by 6 teeth. Paragnaths wedge-shaped with denticles on inner margin. Maxillulary distal endite with 7 armature elements including 3 smooth subterminal outer setae. Maxilla without inner proximal seta on second segment. Pleopod I slender, 1-segmented, bearing 2 normal plumose setae. Uropodal exopod with 2 setae only, ventro-medial seta being absent.

Type locality. India, Andhra Pradesh State, ~ 8 km from Borra Caves in Visakhapatnam District, Karaiguda Cave , 18°18'.33.3''N, 0.83°01'31.9''E, elevation 838 m ( Fig.1 View FIGURE 1 ) .

The cave lies in the dense forest of Araku Valley of the Karaiguda hamlet in Ananthagiri Mandal of Visakhapatnam District, Andhra Pradesh State in southern India. The cave has small entrance that leads to a tunnel which is nearly 10 m long and 4 m wide with three irregular small side chambers. The floor is uneven, with a thick layer of gravel and some massive boulders. The interior of the cave is impressive with young (immature) stalactites and stalagmites. The entrance chamber has a lotic ecosystem, where the sample was collected in contrast to a lentic ecosystem inside the chambers. The abiotic parameters, as determined on 18 June 2013, were as follows: air temperature 31°C; water temperature 22°C; pH 7.1; humidty 88% and turbidity 0.84 NTU. No publications report on the biology of the cave till now.

Material examined. Holotype female dissected on 3 slides (MNHN-IU- 2017-76) and 3 female paratypes are in author’s collection. Collector, S. Shaik, 18 June 2013.

Description of adult female (Holotype). Total body length of holotype 0.7 mm. Body elongate, poorly chitinised and imperforated, 11.5 times as long as wide. In lateral view, pleomeres wider than thoracomeres. Head 1.2 times as long as wide, 1.5 times as long as first 2 thoracomeres combined.

Antennule ( Figs. 2A View FIGURE 2 , 3A View FIGURE 3 ): 7-segmented, 33.3% longer than head; first three segments together 1.6 times longer than next four segments. First segment with 4 plumose setae and 1 simple seta, as illustrated. Second segment with 3 dorsal, plumose setae in a row near outer distal corner and 1 simple seta at inner distal corner. Third segment with 2 unequal simple setae on outer margin. Inner flagellum somewhat squarish, with 3 unequal simple setae. Fourth segment with stout apophysis overreaching midlength of sixth segment and with 2 plumose setae apically and1 plumose seta on small protuberance beside apophysis. Fifth segment smallest, with 1 simple seta at inner distal corner. Sixth segment with 3 unequal simple setae on distal margin, and 2 unequal aesthetascs at inner distal corner. Seventh segment with 4 unequal setae and 2 equal aesthetascs.

Antenna ( Figs. 2A View FIGURE 2 , 3B View FIGURE 3 ): 4-segmented, perpendicular to antennule and 44% shorter than antennule. Exopod shorter than first endopodal segment, with 1 apical seta, which is stout, with bulbous swelling subproximally and bifurcating distally into unusually long, smooth sensory flagella; subapical simple seta absent. Endopod 2- segmented; first segment 0.7 times as long as second segment; plumose seta on second segment absent. Basis unarmed. Setal formula: 0/0+exp/1+0/4.

Labrum ( Fig. 3C View FIGURE 3 ): smooth, apically narrow, somewhat triangular in outline.

Paragnaths ( Fig. 3D View FIGURE 3 ): wedge-shaped, proximally fused with each other, inner margin fringed with 13 denticles on each side.

Mandible ( Fig. 4A View FIGURE 4 ): prehensile. Palp 3-segmented; basal segment slender, somewhat rectangular and slightly shorter than second segment, which is elongately oval; third segment smallest, with 2 unequal sturdy apical setae, about as long as second segment and distal outer margin finely spinulose. Gnathobase fused with basal segment of palp and masticatory part represented by 6 teeth: incisor process (pars incisiva) with two teeth; processus incisivus accessorius with one small tooth but without basal seta; pars molaris with three large and un equal teeth.

Maxillule ( Fig. 4B View FIGURE 4 ): proximal endite with only 1 smooth slender claw. Distal endite subcylindrical, 1.5 times as long as wide, bearing 2 apical claws of equal length, 2 almost equal claws on inner margin, and 3 setae on outer distal margin, close to the apex; all armature elements smooth

Maxilla ( Fig. 4C View FIGURE 4 ): 3-segmented; strongly prehensile. First segment somewhat squarish and bare. Second segment subcylindrical, 1.9 times as long as maximum width and armed with 6 setae distally, as illustrated, and no additional seta on inner proximal margin. Third segment smallest, somewhat trapezoidal, bearing 1 simple seta at inner distal corner and 1 moderately stout, incurved, smooth prehensile, apically inwardly bent claw; claw shorter than second segment.

Th I–VII ( Figs. 5 View FIGURE 5 A–D, 6A–C): length increasing from Th I–III; Th IV–VII nearly similar in size. Th I without epipod; basis with 1simple seta at inner distal corner; seta shorter than first endopodal segment. Th II–VII with somewhat clavate, 1-segmented epipod, overreaching midlength of basis; coxa without plumose seta; basis unarmed. Th I–VII with 2-segmented exopod; Th I first exopodal segment with 2 short, bipinnate setae; Th II–VII first exopod segment with 1 short, dorsal and 1 long, ventral ciliated setae; dorsal ctenidia present distally on Th I– VII, as illustrated. Second exopodal segment shorter than first one and with 2 unequal ciliated terminal setae; Endopod 3-segmented and longer than exopod on Th I, but 2-segmented and distinctly slender and about as long as first exopodal segment on Th II–VII; number and distribution of ctenidia on different segments of Th I–VII as illustrated. Setal formulae: Th I: 0+0/1+0/1; Th II-VII: 0+0/1.

Th VIII ( Fig. 7C View FIGURE 7 ): club-shaped and distinct at base.

Pleopod I ( Figs. 2D View FIGURE 2 , 7B View FIGURE 7 ): 1-segmented, slender, 4.8 times as long as wide, carrying 2 unequal plumose setae, 1 apical and 1 outer subapical. Uropod ( Figs. 2C View FIGURE 2 , 7A View FIGURE 7 ): sympod 2.6 times as long as wide, bearing 3 serrulate, somewhat diagonally arranged, claw-like spines at inner distal corner; proximal-most spine relatively long; distal 2 spines equal in size ( Fig. 7A View FIGURE 7 ). Exopod subapical, 4.0 times as long as wide, with 1 apical and 1 outer subapical ciliated setae; apical seta 2.8 times as long as subapical seta; and ventro-medial seta absent. Endopod nearly cylindrical, 53.4% shorter than sympod, with 3 armature elements: 1 inner subapical serrulate claw-like spine, 1 similar but relatively long inner apical spine both spines somewhat swollen basally; and 1 long outer ciliated seta close to base of apical spine.

Pleotelson ( Fig. 7A View FIGURE 7 ): with 1 strong, dorsal ciliated seta on either side of median axis, not far from base of caudal furca; seta longer than caudal furca.

Anal operculum ( Fig. 7A View FIGURE 7 ): concave medially.

Caudal furca ( Fig. 7A View FIGURE 7 ): as long as distal width and with 4 unequal serrulate spines (1 apical, 3 inner) and 1 long, spiniform ciliated seta at outer distal corner; apical spine longest; 1 complete transverse row of spinules occurring disto-ventrally. Furcal organ not discernible.

Male.— Not known.

Distribution and ecology. Indobathynella socrates n. sp. is so far known only from its type locality. It was collected by coring the sandy sediments of a fast-flowing stream within the cave under typically dark conditions.

Co-occurrence. The new species was accompanied by a dense population of unidentified Copepoda Cyclopoida, Nematoda, Oligochaeta , insect larvae and Parastenocaris Kessler, 1913 sp.

Etymology. The species is named in honor of Socrates, a classical Greek philosopher, who is considered one of the founders of western philosophy. The specific epithet is a noun in apposition to the feminine genus name.