Cyamadusa kaureshi, Thacker & Myers & Trivedi, 2023

Thacker, Dimple, Myers, Alan & Trivedi, Jigneshkumar, 2023, A new species and a new record of the amphipod genus Cymadusa Savigny, 1816 (Senticaudata, Ampithoidae) from India, Zootaxa 5297 (3), pp. 393-405 : 394-398

Cyamadusa kaureshi n. sp.

( Figs 1–4 )

Type material. Holotype male, 11 mm ( LFSC.ZRC-192), Shivarajpur (22º19’53.4’’N 68º56’59.6’’E), rocky shore, 28 February 2022, coll. D. R. Thacker . Paratypes, 3 males, 10–12 mm ( LFSC.ZRC-197) ; 4 females, 8–9.5 mm ( LFSC.ZRC-197), same data as holotype .

Etymology. The new species is named in honor of Professor Kauresh Dhanvantrai Vachhrajani of Department of Zoology, The Maharaja Sayajirao University of Baroda, Vadodara, Gujarat, who has significantly contributed to the study of different groups of crustaceans of Gujarat state, India.

Description. Based on holotype, male, 11 mm

Head. Eyes medium, black (light pink in alcohol). Antenna 1 slightly longer than antenna 2; peduncular article 1 slightly shorter than article 2; article 3 subequal to first flagellar article; flagellum equal to half body length; accessory flagellum with 3 articles, first and third rudimentary. Antenna 2 peduncle article 3 with long plumose setae, peduncular article 4 with comparatively short simple setae; article 1 of peduncle 1.5X broader than long; article 2 longer than article 1; article 3 subequal in length to article 4. Labrum margin setose. Labium distally setose; outer plates notched forming deep cleft. Mandible molar well developed; accessory setal row with 8 plumose setae; palp with 3 articles, article 1 shortest; article 2 with 2 distal setae; article 3 longest with 11 apical and 2 marginal setae. Maxilla 1 inner plate with seven setae; outer plate with 9 setae; palp well developed with 2 articles; article 1 with 11 short robust and 3 long slender setae. Maxilla 2 inner plate with oblique setal row, narrower than outer plate. Maxilliped setose; inner plate shorter and narrower than outer plate; outer plate with 15 robust setae of gradually increasing size; palp three articulate, article 1 and 3 subequal, article 2 subequal in length with article 1 and 3 together.

Pereon. Gnathopod 1 longer and more slender than gnathopod 2; coxa anterior margin forward produced, ventral margin with long setae; basis as long as carpus, without setae and anterodistal lobe strongly produced; ischium small; merus forming long anteroventral lobe; carpus longer than merus, posterior margin moderately setose; propodus oval, moderately setose, palm straight; dactylus longer than palm. Gnathopod 2 coxa longer than broad, posterior margin with plumose setae; basis subequal to propodus, anterior margin moderately setose with plumose setae, strongly produced anterodistal lobe; ischium small, similar to gnathopod 1; carpus strongly setose, anterior margin with plumose setae and posterior margin with simple setae, shorter than propodus; propodus subquadrate, anterior margin strongly setose with plumose setae and posterior margin weakly setose with simple setae, palm entire, straight, with a proximal knob-like process, palmar corner defined by a subacute spine; dactylus curved, shorter than palm. Pereopods 3–4 similar, sparsely setose; merus subequal to carpus; propodus slightly longer and more slender than carpus. Pereopod 5 coxa subquadrate, ventral margin poorly setose; basis expanded; merus subequal to carpus; propodus slightly longer than carpus, posterior margin with row of 6 robust setae and 2 small robust setae near the base of the dactylus. Pereopod 6–7 similar, sparsely setose; basis slightly expanded; merus longer than carpus; propodus longer than merus and carpus, posterior margin with row of 6 robust setae and 2 small robust setae near the base of the dactylus.

Pleon. Epimeron 1 posteroventral corner broadly rounded. Epimeron 2 posterioventral corner narrowly rounded. Epimeron 3 posteroventral corner with small acute cusp and a small seta. Uropod 1 peduncle with long inter-ramal spine, outer ramus is 3.5X as long as inter-ramus spine; rami shorter than peduncle, unequal; endopodite longer than exopodite. Uropod 2 peduncle with very short inter-ramal spine, subequal with endopodite. Uropod 3 peduncle longer than both rami; exopodite shorter than endopodite with two strongly curved apical robust setae; endopodite with slender and robust setae. Telson apically rounded, with marginal and apical setae.

Remarks. A comparison of some important differentiating morphological characters of C. kaureshi n. sp. with Cymadusa sp. and two other closely related species, is given in Table 1. Cymadusa . kaureshi n. sp. differs from C. imbroglio Rabindranath, 1972 , C. cavimana ( Sivaprakasam, 1970) , C. microphthalma Chevreux, 1901 , and C. makranica ( Momtazi, 2022) in lacking any excavations on the male gnathopod 2 palm. This new species also differs from C. makranica in having a densely setose male antenna 2 (weakly setiferous in C. makranica ).

Figures

FIGURE 1. Cymadusa kaureshi n. sp., (a) male paratype: 12 mm (LFSC.ZRC-197); (b) female paratype: 9.5 mm (LFSC.ZRC- 197); Shivrajpur, Gujarat, India. Scale bars—1 mm

FIGURE 2. Cymadusa kaureshi n. sp., male holotype (LFSC.ZRC-192), 11 mm, Shivrajpur, Gujarat, India. Scale bars—0.5 mm.

FIGURE 3. Cymadusa kaureshi n. sp., male holotype (LFSC.ZRC-192), 11mm; Female paratype (LFSC.ZRC-197), 9.5 mm, Shivrajpur, Gujarat, India. Scale bars—1.0 mm.

FIGURE 4. Cymadusa kaureshi n. sp., male holotype (LFSC.ZRC-192), 11mm, Shivrajpur, Gujarat, India. Scale bars—0.5 mm.