Leptestheria nobilis ( Sars, 1900 )

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 : 213-216

Leptestheria nobilis ( Sars, 1900)

( Figs. 8 , 9 )

Leptestheriella nobilis ( Padhye et al. 2011)

Material studied. Four females and three males from University of Pune Pond (UoP pond) (18˚33′17.62″ N & 73˚49′26.80″ E), Pune collected in June 2010 (collected by SMP) .

Redescription. Male.

Head. Broadly rectangular; eyes moderately sized, ocular tubercle conspicuous, shape of ocellus varying but mostly triangular; rostrum dilated and spatulate; occipital condyle prolonged and projecting posteriorly; L/W ratio ~0.9–1.0 with a pointed apex; sharp stout spine present at the tip of rostrum, thrice as long as wide and arched ( Fig.9A )

First antenna. Long & bulbous, twice the length of the base of second antenna; about 5–8 lobes, each lobe lined with several sensillae.

Second antenna. Bi-ramous with varying number of antennomeres, each antennomere bearing spiniform projections (5–8) anteriorly; spines long, slender with an acute tip; plumose setae on opposite sides ( Fig. 8B )

Carapace. Length. 6.7 ± 0.7 mm; Height. 3.6 ± 0.40 mm. Oblong, broadly rectangular, dorsal and anterior margin straight, umbone prominence varying between populations (prominent in ‘tableland’ specimens but not in UoP pond), number of growth lines highly varying, 10–20 easily visible, dark brown or pinkish in coloration when alive.

Trunk. Consists of 23–25 segments, each with a pair of thoracopods and decreasing in size posteriorly. First two thoracopods modified into claspers ( Fig. 8A ).

Thoracopods I & II. Broad, anterior portion of movable finger (endopod) wide but tapering and strongly arching distally (hooklike), apex of which is lined with numerous scales in both the claspers; large palp (endite 5) two segmented, nearly equal in length in the first clasper, distal segment 1.2 times in length than proximal segment in the second clasper; small palp (endite 4 outgrowth) cylindrical, ~2.5 times as long as the width of its base; palm (endite 4) roughly rectangular and projecting obtusely, a medial triangular protrusion observed at base of palm in both claspers gripping area of palm lined with spines which increase in size posteriorly. Other thoracopods having similar structure with 5 endites, an endopodite with digitiform lobes on the exopodites, decreasing in size posteriorly, the last 5–8 very small ( Fig. 8C ). Each of the 8–23 segments has a group of short, posteriorly directed setae with acute apices, the number first increases, and then gradually decreases, a maximum of 7–8 setae per segment is observed.

Telson. Broadly rectangular in outline, dorsal margin arched; the postero-lateral edge ending with a big spine, nearly half the length of the cercopod, curved, without any serration; dorsal margin lined with 30–40 spines, unequal in size and bearing serrations; telson terminal setae originating before the telson spines ( Fig. 9C )

Cercopods. Long and stout, about 0.8–0.9 the length of telson, straight, gradually narrowing to an acute slightly upturned apex; tip reaching the postero-lateral projection of the telson; eighty percent of the dorsal margin lined with small similar sized serrated spinules about 30–45 in number ( Fig. 9C ).

Redescription. Female. Similar to male morphology but with some variations. Rostrum triangular in shape, L/ W ratio of ~ 1.0 ( Fig. 9B ). Ninth and 10th thoracopods modified with extended epipodites for carrying eggs. Telson dorsal margin more gently arched than male and lined with 30–40 spines on the dorsal margin ( Fig.9B ), cercopod morphology as in male ( Fig. 8D )

Carapace. Length 6.2 mm ± 0.4 mm; height 4 mm ± 0.3 mm.

Egg. Spherical and with no ornamentation ( Figs.4C & D in Padhye et al, 2016)

Remarks. The morphology of Leptestheria nobilis is highly variable ( Simhachalam & Timms, 2012), although some of the characters observed in these populations, such as the shape of the occipital condyle and the structure of the cercopod, coincide with previous and original descriptions ( Daday, 1923; Sars, 1900). Leptestheria dumonti Subash Babu & Bijoy Nandan, 2010 and Leptestheria simhadrii ( Simhachalam & Timms, 2012) are very similar to L. nobilis in terms of their morphology and thus their species validity needs to be checked using integrative approaches. The studied population could also represent a distinct cryptic species, though, this cannot be confirmed unless topotypic information is obtained. This species was found in assemblages (see Padhye & Dahanukar, 2015 for all combinations of assemblages) or occurred alone.

Figures

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 8. Leptestheria nobilis. A. Habitus (male), B. Second antenna (male), C. Clasper I (male), D. Cercopod (male) (Scale bars 1mm for A, 0.5 mm for B, D, 0.25mm for C).

FIGURE 9. Leptestheria nobilis. A. Head (male), B. Telson (male), C. Head (female), D. Telson (female) (Scale bars 1mm for A–D).