Eulimnadia azisi, Babu, K Subhash & Nandan, Bijoy, 2010

Babu, K Subhash & Nandan, Bijoy, 2010, Two new clam shrimp species (Crustacea: Branchiopoda: Spinicaudata) from Kerala, India, Zootaxa 2713, pp. 55-64 : 59-62

Eulimnadia azisi sp. nov.

( Figs. 2 –3)

Etymology. The specimen is named in honour of Prof. Dr. P.K. Abdul Azis, the former Vice-Chancellor, Cochin University of Science & Technology, India. Abdul Azis has made valuable research contributions in wetland science and trophic dynamics in relation to species variability.

Type locality. Specimens were collected from a small rainwater rocky pool at Vettilapara, Western Ghats region, Kerala (10° 31′ N and 76° 20′ E). Collections were made by K. K. Subhash Babu on 3rd August 2008.

Holotype. Adult female egg bearing, fixed in 4% formalin. Reg. no. MBM/ Ch/ 21/ 09).

Paratypes, 2 adult females with eggs (one disarticulated) fixed in 4% formalin and deposited in the Zoological Survey of India Museum, Western Ghats Station, Calicut, Kerala-State, India.

Diagnosis. Carapace elliptical with 4–5 growth lines. Head with characteristic frontal organ on the mid dorsal area. 18–20 pairs of thoracopods. Lower distal angle of the telson produced to from an acute point. Telson serrated on dorsal margin with 9–10 unequal spines and telsonic setae inserted between 4th and 5th spines. Eggs are spherical and rugose with 14 alveoli-like facets.

Description. Female Size. Length 3.3 mm; height 2.8 mm.

Carapace thin, transparent and somewhat oval, with 4–5 growth lines. Growth lines more prominent at carapace margin (Fig. 3K). Maximum height about one third from the anterior region of the carapace ( Fig. 2 A). Dorsal margin convex with evenly arched hinge line. Ventral margin convex and smooth.

Head somewhat rectangular with a slight anteroventral notch. Frontal organ present ( Fig. 2 B, 3M). Eye large, ocellus triangular and situated anteroventrally.

First antenna with 7 sensory lobes ( Fig. 2 C), each sensory lobe with a tuft of sensillae.

Second antenna strong, biramous with seven antennomeres; each antennomere with spines and plumose setae arranged on opposite sides ( Fig. 2 D).

Thoracopods. Trunk arched and segmented with 18 pairs of thoracopods (Fig. 3L). All thoracopods basically similar in structure but reducing in size posteriorly. First thoracopod with five endites on its medial edge and fringed with plumose setae. First endite (gnathobase) is armed with a pair of sharp spines, exopod ornamented with long plumose setae and endopod small with setae ( Fig. 2 E). Ninth and 10th thoracopods with flabellum modified to carry eggs.

Eggs were glued and deposited on the either side of the mid dorsal area of the mature female. Up to 200 eggs were noted in a single female. Eggs spherical and ornamented with 14 alveolar like facets and average size was 150μm (Fig. 3O; Fig. 2 H).

Body. Mid-dorsal area of 11th segment with a dorsal transverse ridge bearing setae; posterior to eleventh segment, all segments with setae.

FIGURE 3. Leptestheria dumonti sp. nov. (SEM) (A–J), A. Carapace with prominent umbone and growth lines, B. Male (lateral view, without valve), C. Telson dorsal spines (male), D. Dorsal spines enlarged, E. Cercopod (lateral view), F. Clasper (lateral view), G. Palm and 5th endite of male clasper, H. Rostrum (female), I. Telson spines (female), J. Cercopod. Eulimnadia azisi sp. nov. (SEM) (K–O), K. Carapace margin, L. Telson and cercopod, M. Head (distorted head due to bad preservation), N. Cercopod, O. Egg.

Telson rhomboidal in lateral view with 9–10 unequal spines on its dorsal margins ( Fig. 2 F). Terminal telsonic seta attached in between 4th and 5th spines. Cercopod large and fringed with 9–11 long setae, cercopod terminating with an acute spine, with a smaller subtending spine. (Fig. 3N); Cercopod with dorsal concave margin serrated.

Ecology. Eulimnadia azisi sp. nov. was collected from a rainwater filled rocky depressions at Western Ghats, Kerala in the monsoon season (June–August). The pool was devoid of vegetation and water was dark brownish in colour due to the abundant organic matter. pH was slightly basic, ranging from 7.8 to 8.2. E. azisi sp. nov. was found co-occurring with a large number of cyclopoid copepods ( Mesocyclops agunu s Onabamiro, 1957, Thermocyclops decipiens (Kiefer, 1929) , the cladoceran, Moina micrura Kurz, 1874 ), unidentified ostracods, and dragonfly larvae.

Remarks. Eulimnadia azisi n. sp is quite similar to E. michaeli Nayar and Nair, 1968 . In both case the eggs are spherical in shape and ornamented with alveolar like facets. The position of the telsonic setae; number of plumose setae on cercopod; fewer egg facets and absence of males are the main distinguishing features separating E. azisi from E. michaeli . In E. azisi sp. nov. there are 14 facets on egg, whereas in E. michaeli there are 26. The external morphology of resting egg is a useful additional taxonomical character in Eulimnadia (Belk, 1989; Martin & Belk, 1989; Brendonck et al. 1990). The telson dorsal margin has 18 pairs of spines on E. michaeli but only 11 pairs in E. azisi sp. nov.; both have a prominent spine at the base of cercopod and 18 pairs of spines on the telson dorsal margin, while in E. azisi sp. nov. only 11 spines are present, with one prominent basal spine at the base of the cercopod. The number of cercopod spines in E. azisi sp. nov. are 9–10 and telsonic setae are inserted between the 3rd or 4th spine pairs, whereas E. michaeli has 18 cercopod spines and telsonic setae are inserted between spine pairs 6th or 7th. In E. michaeli , there are 15 cercopod plumose setae whereas in E. azisi n. sp there are 13. E. azisi n. sp second antennae have 7 antennomeres, and E. michaeli has 8–9. Males have been reported in E. michaeli whereas in E. azisi sp. nov. no males were found during six years of studies. Weeks et al. (1997) also reported the possibility of pure hermaphrodite population among Eulimnadia .

Compared with E. azisi sp. nov., Eulimnadia ovata from Rajasthan ( Nayar, 1965) is larger (7.5 mm), more broadly oval in shape, has 4–5 growth lines, eight antennomeres in the second antenna, a short, obscure spine under the cercopod base, and the rostrum is rounded. Another similar species is E. gunturensis from Andhra Pradesh (Radhakrishna & Durga Prasad, 1976), but it differs by having both males and females, a more rounded head and 9 antennomeres in the second antenna.

Figures

FIGURE 2. Eulimnadia azisi sp. nov. (female) (A – H) A. Carapace growth lines, B. Head, C. First antenna with sensory lobes, D. Second Antenna (lateral view), E. First thoracopod (typical), F. Telson with unequal dorsal spines, G. Telson (posterior portion enlarged), H. Egg.