Leptestheria chalukyae, Padhye & Kulkarni & Pagni & Rabet, 2023

Padhye, Sameer M., Kulkarni, Mihir R., Pagni, Marco & Rabet, Nicolas, 2023, New leptestherid clam shrimps (Pancrustacea: Branchiopoda: Spinicaudata Leptestheriidae) from peninsular India, Zootaxa 5264 (2), pp. 205-220 : 208-210

Leptestheria chalukyae sp. nov.

( Figs.3 , 4 , 6A , 7A )

Leptestheria sp. M128 ( Schwentner et al. 2020)

Etymology. The species is named after the great medieval Indian dynasty called Chalukyas (Badami Chalukyas) who ruled large parts of Southern/Central India and whose capital was Badami where these specimens were collected from.

Type locality. A rock pool dug in red sandstone near Badami fort ( India: Karnataka) (15°55′17″N, 75°41′3″E; Date of collection of sediment, Oct 2016) .

Type material. Holotype. One male (4% formalin + glycerin) deposited at the Western Regional Centre of Zoological Survey of India ( ZSI), Pune (Registration number: ZSI-WRC C.2073).

Other material studied. Two females.

Description. Male (holotype).

Head. Broadly rectangular. Eyes large, noticeable ocular tubercle. Ocellus elongated and irregularly shaped, located at middle of rostrum. Prominent fornix. Rostrum broad and spatulate, occipital condyle rounded, barely projecting, spine present at the tip of rostrum ( Fig.3B ), spine nearly three times as long as wide and gently arching.

First antenna. Antenna long, bulbous, more than two times the length of base of second antenna; about 10–14 lobes present on dorsal margin, each lobe lined with several sensillae.

Second antenna. Bi-ramous, endopod and exopod with 14 flagellomeres ( Fig.3C ), length nearly twice the head length, each flagellomere bearing about 3–8 long posteriorly projecting spines with acute apices and plumose setae on opposite sides, flagellomere size decreasing posteriorly.

Carapace. Length 7.6 mm; Height 3.4 mm. Oblong, dorsal and ventral margin straight, umbone prominent located on the anterior 1/3 rd of the carapace. Carapace with 10 + distinct carapace lines, light brown in coloration ( Fig.3A ), ventral margin lined with fine setae.

Trunk. Consisting of 26 segments ( Fig.3C ), each with a pair of thoracopods and decreasing in size posteriorly, the last eight being the smallest.

Thoracopods I & II. Modified as claspers. Both claspers large. Movable finger (endopod) broad anteriorly but narrowing and hook like distally in both claspers. Large palp (endite 5) two segmented in both claspers, both segments nearly equal in length in first clasper; distal segment about 1.3 times in length than proximal segment in the second clasper. Small palp (endite 4 outgrowth) cylindrically shaped, 2.5x as long as broad, directed posteriorly in both claspers, palm (endite 4) rectangular, as long as broad in the first clasper, marginally longer than broad in the second clasper, triangular protrusion observed medially at base of palm in both claspers, gripping area of the palm with small tubercles (smallest as long as broad) anteriorly and increasing gradually in size posteriorly ( Fig. 4A ). Other thoracopods having similar structure with 5 endites as the other members of the genus, decreasing in size posteriorly, the last eigth very small.

Segments 16–26, each bearing bunch of stout posteriorly directed setae with acute apices dorsally ( Fig. 3D ), number increasing anteriorly first and then gradually decreasing, maximum of 6–7 setae are seen per segment.

Telson. Broadly rectangular in shape. Dorsal margin distinctly arched, the lateral edge ending with a big spine, ~0.4 times the length of the cercopod. Dorsal margin with ~30 irregularly sized spines, longest spines twice as long as broad and 2.5 times as long as the smallest spines. Telson filaments between 1 stand 3 rd marginal spines ( Fig.4B ).

Cercopod. Long, about 0.8 times the length of dorsal margin of telson, tapering posteriorly; margin gently curved until 2/3 rd of the length, tips dorsally and gradually upturned, tip at the same level as the postero-lateral projection of the telson; 2/3 rd of the anterior part of the dorsal margin lined with about 30 similar sized spinules, equally spaced ( Fig. 4B ).

Female. Similar to male morphology but with some variations.

Carapace size. Length 6.7 & 6.3 mm; Height 3.4 & 3.2 mm.

Rostrum triangular, rostral spine long, ~4 times as long as broad at the base; occipital condyle similar to male ( Figs. 3E , 7A );

Telson. Dorsal edge less convex than male lined with about 20 irregularly sized spines ( Fig.6A ).

Cercopods highly arched, spines on the dorsal margin gradually increasing posteriorly with last 6–7 spines being about 0.7–0.8 times that of the breadth of the thickest region of the telson spine ( Fig. 3F ).

Remarks. The female described here was used (few limbs) for obtaining sequence which were subsequently used to generate the phylogeny by Schwentner et al. 2020 (coded M128; Fig 2 in Schwentner et al. 2020). This species differs from the rest of Indian species based on the occipital condyle shape/length and the very big cercopod marginal spines in males. The rounded occipital condyle of L. chalukyae sp. nov. resembles with Eoleptestheria species ( E. ticinensis (Balsamo-Crivelli, 1859)) . It is also relatively similar to the Indian species L. sarsi described from Telangana (a southern state in India). The cercopod spine size and arrangement in the male differs in these species with L. sarsi having 6–8 very big spines (length of the biggest spine is nearly 0.7–0.8 times the thickest region of the cercopod) near the tip of the cercopod ( Fig.3D in Padhye & Rabet, 2017) which is absent in L. chalukyae sp. nov.. The female condyle is relatively elongated in L. sarsi female ( Fig. 3B in Padhye & Rabet, 2017). Remarkably, both L. chalukyae and L. sarsi were reported from rock pools suggesting potential local diversification of these temporary-water specialist organisms in peninsular India. Eulimnadia chaperi (Simon, 1886) was seen coexisting with L. chalukyae sp. nov.

Figures

FIGURE 2. Occipital condyle shapes seen in Indian leptestherids. A. Rounded, B. Projecting, C. Prolonged.

FIGURE 3. Leptestheria chalukyae sp. nov. A. Carapace (male), B. Head (male), C. Habitus (male), D. Dorsal armature (male), E. Head (female), F. Cercopod tip (female) (Scale bars 1mm for A,B,C,E, 0.5mm for D, 0.1 mm for F).

FIGURE 4. Leptestheria chalukyae sp. nov. A. Clasper I (male), B. Telson (male) (Scale bars 0.25 mm for A, 0.5 mm for B).

FIGURE 6. Leptestheria chalukyae sp. nov. A. Telson (female); Leptestheria gomantaki sp. nov. B. Telson (female) (Scale bars 0.5 mm for A–B).

FIGURE 7. A. Leptestheria chalukyae sp. nov. Head (female), B. Leptestheria gomantaki sp. nov. Telson marginal spines (female).