Eocyzicus bouvieri Daday, 1913

Padhye, Sameer M. & Rabet, Nicolas, 2017, Re-description of two spiny clam shrimps (Crustacea: Branchiopoda: Spinicaudata) of the Indian subcontinent from Daday de Dees's collection at MNHN with new insights on the validity of Eulimnadia compressa (Baird, 1860) and Eulimnadia chaperi (Simon, 1886), Zootaxa 4294 (3), pp. 349-360 : 350-353

Eocyzicus bouvieri Daday, 1913

( Fig. 1 , 2 )

Material examined. MNHN-IU-2007-754 (= MNHN-Bp47): Two males and one complete female; one female head.

Locality. Bhovali Bazar, Kumaon (Bhowli Bazar, Uttarakhand, India)

Description. Male. Head broadly quadrangular; ocular tubercle not conspicuous; eyes circular and about 0.4 times the size of ocular tubercle; naupliar eye not clearly seen; rostrum spatulate, rostral apex pointed; occipital condyle not projecting with straight dorso-posterior margin ( Fig. 2 A).

First antenna pedunculated; 16–18 irregular lobes, each one bearing a patch of sub-terminal and terminal sensory setae.

Second antenna peduncle tubular about 0.4 times the head length, lined with oblique rows of plumose setae anteriorly. Both antennal flagella (exopod and endopod) with 14 flagellomeres ( Fig. 1 D). Each flagellomere cylindrical with 5–7 long anteriorly directed spines and 5–7 longitudinal row of setae on posterior side.

Carapace broadly oval in lateral view; dorsal margin straight with prominent umbone, 12 visible carapace growth lines; ventral margin evenly convex ( Fig. 1 A) without any setation; polygonal markings present on carapace valves. Length: 5.2 and 5.4 mm; height: 3.1 and 3.2 mm.

Twenty four–twenty six pairs of thoracopods present, first two modified into claspers in males.

Clasper broad; movable finger (endopod) broad anteriorly but narrowing and hook like distally; tip at distal end with many small scales; large palp (endite V) two segmented and in both claspers, length of both segments nearly equal in first clasper; distal palpomere (endite V outgrowth) slightly elongated than proximal segment; in second clasper, small palp (endite IV outgrowth) in both claspers cylindrical in shape, twice as long as broad, directed posteriorly in the first and anteriorly in the second, their tips with fine setae; palm (endite IV) broadly rectangular, slightly longer than broad, medial protrusion at base of palm not seen in first but broadly convex on clasper 2 ( Fig. 2 C), gripping area of the palm lined with small spines increasing in size posteriorly, smaller spines roughly conical with blunt apex while larger ones with more acute apices ( Fig. 2 C).

Other thoracopods similar in structure but reducing in size posteriorly.

Abdomen. Dorsal margin of the posterior body segments (last 10–12) with a dorsomedial projection lined with 4–5 long posteriorly directed and curved spines, 3–5 of the last segments with bifurcated stout apices ( Fig. 2 E)

Telson (Broken; Fig. 1 D) broadly rectangular; postero-lateral edge armed with 22–24 conical, curved and bilaterally serrated pairs of spines of unequal sizes, longest about 0.7 times the width of cercopod base, smallest spines 1/3rd the length of the longest; postero-lateral edge ending in an arched and acute spiniform projection serrated on its dorsal margin and half the length of the cercopod; caudal filaments originating between the second and third pair of spines of the telson ( Fig. 1 D for gross morphology, Fig. 2 D for details). Cercopods as long as the postero medial edge of telson, tapering distally; a few (exact number indeterminable, 2–3 seen) plumose setae present till about proximal 1/3rd and lined with pecten distally; single small serrate spine present immediately after the plumose setae, length about 0.3 times the thickness of the cercopod at point of attachment, apex gently arched ( Fig. 1 D for gross morphology, Fig. 2 D for details).

Female slightly smaller than male; rostrum triangular with a pointed apex; occipital crest without an angle ( Fig.2 B); about 26 pairs of trunk limbs present, IX and X limbs with modified epipodites for carrying eggs; dorsal armature like in male; telson similar in shape but with larger proportion of the longer postero-medial spines, cercopods similar to male ( Fig.2 D).

Size. Length of the two males: 5.2 and 5.4 mm; height: 3.1 and 3.2 mm. Female length: 5 mm; height: 3 mm

Figures

FIGURE 1. Eocyzicus bouvieri Daday, 1913. A, carapace. B, second antenna (part). C, spine on the cercopod. D, telson (male; broken). Scale bars: A: 1 mm; B: 0.05 mm; C: 0.1 mm; D: 0.5 mm.

FIGURE 2. Eocyzicus bouvieri Daday, 1913. A, male head. B. female head. C, gripping area of the palm of the clasper 2. D, telson and cercopod (female) (arrow indicating the posteriormost spine, taken from second female). E, dorsal armature. Scale bars: A & B: 0.5 mm; C & D: 0.2 mm; E: 0.05 mm.