Ceradomaera plumosa Ledoyer, 1973

Thacker, Dimple, Myers, Alan A. & Trivedi, Jigneshkumar N., 2024, On a small collection of Maeridae Krapp-Schickel, 2008 (Crustacea: Amphipoda) from Gujarat, India, Zootaxa 5474 (5), pp. 563-583 : 569-574

Ceradomaera plumosa Ledoyer, 1973

( Figs 1B , 5–8 )

Ceradomaera plumosa Ledoyer, 1973 , 65, figs 11–13.

Material Examined. 3 males, 10–11.5 mm; 5 females, 8–12 mm, ( LFSC.ZRC-215) Zanzmer (21.1830 N 72.0764 E), 26 March, 2023, coll. D. R. Thacker .

Description. Based on male, 11.5 mm.

Head. Eyes large, ovate. Antenna 1 longer than antenna 2; flagellum shorter than peduncle; peduncular article 1 0.94 times as long as article 2, article 3 one fifth of the length of article 2; accessory flagellum 6–7 articulate (fig. 5, A1). Antenna 2 0.55 times as long as antenna 1, peduncular article 4 1.20 times as long as article 5; flagellum 13 articulate (fig. 5, A2). Mandible accessory setal row well developed with 7 setae; palp 3 articulate, article 1 with acute distal tooth spine, article 3 0.22 times longer than article 2; article 3 0.15 times longer than article 2 (fig. 5, Md). Labium distal margins of outer lobes setose (fig. 5, L). Labrum thickened (fig. 5, Lb). Maxilla 1 inner plate bullet shaped with 4 distal plumose setae; outer plate with 8 apical robust setae; palp article 2 distally setose (fig. 5, Mx1). Maxilla 2 inner plate broader distally; inner plate dorsomedial surface with a small oblique row of setae (fig. 5, Mx2). Maxilliped inner plate epically truncate with 8 apical and 1 marginal plumose seta; outer plate with 7 long to medium robust setae on distal margin, 12 small robust setae on inner margin; palp 4 articulate, article 4 with a long apical robust seta (fig. 5, Mxp).

Pereon. Gnathopod 1 coxa anteroventral corner acute with few simple setae on ventral margin; basis subequal to carpus, posterior margin with few setose, posterodistal corner with a tuft of simple setae, ischium with a tuft of simple setae on posterodistal corner; merus posterior margin setose; carpus anterior margin with a single seta, posterior margin densely setose with posterodistal corner with 6 thick plumose setae, propodus 0.80 times as long as carpus, oval in shape, anterior margin with few small setae, posterior margin densely setose with 3 long spines behind the palm, palm convex with few small spines; dactylus subequal to palm (fig. 6, G1). Gnathopod 2 asymmetrical. Left Gnathopod 2 larger than right gnathopod 2, basis nearly half the size of propodus, posterior margin with few long setae, ischium smaller than merus; carpus subtriangular, posterodistal corner rounded with few setae; propodus large, subovoidal, palm acutely transverse with 2 subrectangular shelves, palm dorsal margin with few spines and setae, palm ventral margin with few small and 3 long spines; dactylus 0.80 times as long as palm (fig. 6, G2).

Pereopod 3 longer than pereopod 4; coxa subquadrate, basis posterior margin with 2 long and 2 small simple setae; merus 1.18 times as long as carpus, with 3 long spines on anterior margin and few setae on posterior margin; carpus subequal to propodus, anterior margin bare, posterior margin with 6 small to medium spines; propodus anterior margin bare posterior margin with four pairs of small setae, dactylus 0.38 times as long as propodus (fig. 6, P3). Pereopod 4 coxa broader than long; basis with some small setae on anterior margin, on posterior margin 6 long and 3 small setae, one medium seta on posterodistal corner; merus 1.20 times longer than carpus, anterior margin with 2 long spines, posterior margin with some setae; carpus, propodus and dactylus similar to pereopod 3 (fig. 6, P4). Pereopod 5 basis subrectangular with anterodistal corner produced; merus 0.71 times as long as carpus with 1 spine on anterior margin and 3 on the posterior margin; carpus 1.27 times as long as propodus; propodus with 2 spins on anterior margin, 2 single spines and 3 pair of spines on posterior margin; dactylus 0.30 times as long as propodus (fig. 6, P5). Pereopod 6–7 similar, basis subquadrate, with robust setae on anterior margin and small setae on posterior margins; merus 0.67 times as long as carpus, carpus 1.16 tomes as long as propodus; dactylus 0.30 times as long as dactylus (fig. 7, P6 & P7).

Pleon. Epimeron 1 without dorsal teeth, ventral and posteroventral teeth present. Epimera 2–3 with dorsal, posteroventral and ventral teeth; ventral margin with 3 and 4 robust setae respectively (fig. 5, Ep1–3). Epimeron 3 to urosomite 3 have small hairs dorsally (fig. 5, Ep1–3 & Us1–3). Uropod 1 peduncle 1.67 times as long as outer ramus, with well-developed basofacial seta and long spur at distal margin; outer ramus a little longer than inner ramus (fig. 7, U1). Uropod 2 peduncle 0.94 times as long as outer ramus; inner ramus slightly shorter than outer ramus (fig. 7, U2). Uropod 3 peduncle 0.48 times as long as subequal rami (fig. 7, U3). Telson deeply cleft, 1.13 times broader than long, both halves pointed distally, each half with 1 plumose seta on outer margin and 1 long and 1 short robust distal seta (fig. 7, T).

Female (sexually dimorphic characters). No sexual dimorphism. Developmental stages of female Gnathopod 2 have been illustrated in fig. 8 ( Fig. 8 ).

Geographical distribution. Madagascar ( Ledoyer 1973) and India. In India, the species is reported from Kerala ( Barnard 1935), Tamil Nadu, Andhra Pradesh ( Sivaprakasam 1968), Odisha ( Chilton, 1921), Bay of Bengal ( Surya Rao, 1972), Gujarat (Present study).

Remarks. The specimen examined here agrees with the description and illustrations of C. plumosa given by Ledoyer (1973). However, the specimen examined here shows some variations, such as: specimen examined here has gnathopod 1 propodus oval in shape (fig. 6, G1) (vs. subrectangular in C. plumosa cf. Ledoyer 1973, fig. 11, Gn1), epimera 1 and 2 ventral margin with 2 and 1 tooth respectively (fig. 5, Ep1 & 2) (vs. 0 and 5 teeth respectively cf. Ledoyer 1973, fig. 11, Ep1 & 2). The specimen examined here (11.5 mm) is larger than the specimen of Ledoyer (1973) (7 mm); thus, these variations could be because of the size difference.

Figures

FIGURE 1. (A) Ceradocus (Denticeradocus) alama Myers & Nithyanandan, 2016 male, (LFSC.ZRC-214): 10 mm, Shivrajpur; (B) Ceradomaera plumosa Ledoyer, 1973, male (LFSC.ZRC-215): 10 mm, Zanzmer; (C) Maera gujaratensis sp. nov., male paratype, (LFSC.ZRC-210): 7 mm, Gopnath; (D) Quadrimaera okha sp. nov., male paratype, (LFSC.ZRC-213): 4.5 mm, Shivrajpur, Gujarat, India.

FIGURE 5. Ceradomaera plumosa Ledoyer, 1973, male (LFSC.ZRC-215): 11.5 mm, Zanzmer, (21.1830 N 72.0764 E), Gujarat, India.

FIGURE 6. Ceradomaera plumosa Ledoyer, 1973, male (LFSC.ZRC-215): 11.5 mm, Zanzmer, (21.1830 N 72.0764 E), Gujarat, India.

FIGURE 7. Ceradomaera plumosa Ledoyer, 1973, male (LFSC.ZRC-215): 11.5 mm, Zanzmer, (21.1830 N 72.0764 E), Gujarat, India.

FIGURE 8. Ceradomaera plumosa Ledoyer, 1973, female (LFSC.ZRC-215): 8–12 mm, Zanzmer, (21.1830 N 72.0764 E), Gujarat, India.