Cyzicus

Padhye, Sameer, Rabet, Nicolas & Ghate, Hemant, 2015, First faunal inventory of large branchiopods (Crustacea: Branchiopoda) of Western Maharashtra, India with taxonomical and distributional comments, Zootaxa 3904 (2), pp. 208-222 : 212-213

Cyzicus sp.

( Figs. 4 –5)

Material examined. Five females studied from Dighi pools, Pune (Aug 2009).

Description. Female. Head. Rostrum roughly triangular, rostral apex pointed and slightly upturned. Ocular tubercle not conspicuous, eyes moderate sized and circular, naupliar eye elongated. Occipital crest situated at the dorsal/posterior margin of the head, conical and extended posteriorly; length equal to its basal width and with a deep gap separating it from dorso-posterior part of head ( Fig.4 C).

First antennae. Positioned posterior to rostrum, about 0.6–0.7 times the length of second antenna. Pedunculate with sixteen irregular lobes with each lobe bearing a patch of sub-terminal and terminal aesthatacs (Fig.5 A).

Second antennae. Length twice that of the head. Base tubular, lined with transverse rows of plumose setae followed by posteriorly directed spines. Antennal rami with twelve (exopod) and thirteen flagellomeres (endopod) ( Fig.4 D). Each flagellomere cylindrical with 4–5 long spines on anterior side and a longitudinal row of setae on posterior side (Fig.5 B).

Carapace. Carapace broadly oval in lateral view ( Fig.4 A, B), reddish translucent in color, umbone prominent ( Fig. 4 B). Hinge line straight, with a single distinct stout apex at the growth line tip ( Fig.4 B ‘arrow’). Anterior one third portion of the carapace margin lined with small, stout, curved spines ( Fig.4 E). Numerous carapace lines observed (not counted) ( Fig.4 : B), each line fringed with short bristles; bristles conspicuous along the peripheral growth lines ( Fig.4 F).

Trunk. 16–20 pairs of thoracopods present ( Fig. 4 A). All thoracopods similar in structure but reducing in size posteriorly. Dorsal margin of the posterior body segments (lower half of the body) with a dorsomedial lobiform projection, tapering anteriorly and directed posteriorly to form a spine like apex (Fig. 5, C ‘arrow’). The lobiform projection lined with varying number of smaller posteriorly directed and curved spines (Fig. 5, C). The lobiform projection diminishes in size towards the end segments.

Telson. Postero-lateral edge armed with 18–22 roughly conical, curved and bilaterally serrated pairs of spines, distalmost spines twice in length than the proximal spines (Fig. 5D ‘arrow’). Postero-lateral edge ending in a stout, arcuate and acute, unilaterally serrated projection at least 3 times longer than the nearest spines (Fig.5 D ‘star’). Caudal filaments originating on an elevated and roughly semicircular mound between the second and third pair of spines of the telson (Fig. 5 D). Cercopods projecting posteriorly, cerci longer than telson with setiferous bristles covering nearly 1/3rd of dorsal margin proximally followed by a small serrated spine in the middle, and a row of smaller spines along the distal marginal border (Fig.5 D).

Male. Not seen

Size. Length: 4.08 ± 0.90 mm; Height: 2.8 ± 0.69 mm.

Known distribution: Seen so far only in habitats on the outskirts of Pune city.

Remarks. The genus Caenestheriella shares many characters with the genus Cyzicus and hence few authors have synonymized the former with Cyzicus ( Straskraba 1965; Brtek 1997) giving recent phylogenetic studies more evidence ( Schwentner et al. 2009). It is necessary to re-examine all the species described under that genus from India ( Rogers et al. 2013). This species was very rare and found in only one season. We were not able to find males, so comparison of male specific characters could not be done. Hence, because of lack of comparative material, dearth of reliable literature and absence of males, we report this species as only Cyzicus sp.

Figures

FIGURE 4. Cyzicus sp. from Dighi, Pune. A, Habitus. B, Shell. C, Head. D, Second antenna. E, Serrated margin on the anterior region of shell. F, setae on the margin of the shell. (Scale bars: A, B and D 1 mm; C, E, F 0.1 mm).