Quadrimaera mirandella, Appadoo & Myers & Fagoonee, 2002

Appadoo, Chandani, Myers, Alan A. & Fagoonee, Indur, 2002, The genera Quadrimaera and Maera (Amphipoda: Gammaridea: Melitidae) from Mauritius, Journal of Natural History 36 (6), pp. 641-673 : 646-649

Quadrimaera mirandella sp. nov.

(®gures 3, 4)

Type material. HOLOTYPE: 1, 3.5 mm, AM P60087 ; PARATYPES: 1 (microscope slides), AM P60088, 1 , AM P60089, 1 (microscope slides and carcass), AM P60090, from Acanthophora spicifera (Vahl) Borgesen, Anse la Raie (19ss59.5¾S 57ss37.5¾E), 15 May 1998 .

Description

Male. Length, 3.7 mm. Head without subocular notch; eyes subovate. Antenna 1 peduncle article 1 with stout robust setae on ventral margin; peduncle article 2 a little longer than article 1; article 3 one-third length of article 2; primary ¯agellum 14-articulate, accessory ¯agellum six-articulate. Antenna 2 moderately setiferous, peduncle article 5 shorter than 4; ¯agellum six-articulate. Mandible palp article 2 with three setae on outer margin; article 3, 1.2 times as long as article 2, article 3 with three apical setae and four marginal setae. Labium with rounded mandibular lobes. Maxilla 1 inner plate with three terminal setae and a few marginal setae. Maxilla 2 outer plate distinctly wider than inner plate, inner plate with few marginal setae. Maxilliped palp article 3 with setae on distal and part of lateral margin. Gnathopod 1 coxa subquadrangula r and antero-distall y rounded, with setae on ventral margin; basis 2.6 times as long as wide; carpus anterior margin with subdistal excavation; propodus palmar margin convex, with short robust setae and groups of ®ne setae; dactylus ®tting palm. Gnathopod 2 basis more than twice as long as broad and produced anterodistally into a lobe; carpus reduced, cup-shaped; propodus subquadrate with transverse palm, palmar margin with one deep medial excavation, posterior to which is a ¯at-topped process and at the postero-distal corner, a short distal tooth preceded by a V-shaped excavation; palm with a number of robust setae; dactylus medially expanded and tapering at the tip. Pereopod 3±4 basis more than three times as long as broad, with short setae on anterior margin; merus distally produced; dactylus bi®d. Pereopod 5 basis subquadrate, 2.6 times as long as broad, with robust setae on anterior and posterior margins; merus slightly produced distally and bearing long setae. Pereopod 6 basis subquadrate, 1.8 times as long as broad; merus and carpus with robust setae. Pereopod 7 similar to pereopod 6 but basis 1.4 times as long as broad. Epimeron 3 subquadrate with a small projection at the ventrodistal corner and with three robust setae on the antero-ventral margin. Uropod 1 peduncle and rami with many robust setae; rami subequal, shorter than peduncle. Uropod 2 peduncle with two robust setae; outer ramus slightly shorter than inner ramus and subequal to peduncle. Uropod 3 peduncle with two robust setae; rami relatively slender, outer ramus slightly the longer, 1.4 times length of peduncle both rami with four to ®ve distal robust setae. Telson cleft to three-quarter its length; lobes blunt without teeth and bearing four to ®ve long robust setae shorter than telson.

Female. Length, 3.3 mm. Gnathopod 1 similar to that of male. Gnathopod 2 palm of propodus with excavations similar to that of male.

Remarks

Q. mirandella sp. nov. has a smooth postero-distal margin to epimeron 3 which separates it from Q. serrata . The truncated telson is similar to that of Q. quadrimana , and also that of Q. cristinae from Bermuda (RuOEo et al., 2000). It is distinguished from these two species by having only one medial excavation on the palm of gnathopod 2. It also closely resembles Q. schellenbergi from the Red Sea (RuOEo, 1938), but is distinguished from it by lacking dense setae on the basis of pereopods 6 and 7. The presence of ®ve to six robust setae on the telson lobes makes Q. mirandella show a nity with two Bermudan species Q. miranda and Q. ceres (RuOEo et al., 2000) and also distinguishes it from species having three or four robust setae ( Q. paci W ca, Q. caliban (RuOEo et al., 2000), Q. reishi ( Barnard, 1979) and Q. chinnara ( Barnard, 1979)) . Q. mirandella most closely resembles Q. miranda in the palm of the gnathopod 2 which has a medial excavation with a`molar’ shaped hump and in the telsonic lobes which are evenly truncate distally. Other features shared by Q. mirandella and Q. miranda (RuOEo et al., 2000) are the short article 2 of the mandible palp, the rounded anterior margin of coxa 1, the ināted posterior margin of the gnathopod 2 dactylus and the ovate-elongate basis of pereopods 5±7. It diOEers, however, from that species in the more elongate uropod 3 rami, the shorter setae on the posterior margin of the perepods 6±7 propodus and the shorter robust setae on the telson (shorter than telson in Q. mirandella , longer than telson in Q. miranda ). In addition, Q. mirandella is a smaller species (3.7 mm) than Q. miranda (5.0 mm).

The authorship of this new species lies with Appadoo and Myers.

Type locality. Anse la Raie , Mauritius .

Distribution. Known only from Mauritius.

Etymology. A diminutive of`miranda’ denoting its small size and general similarity to the species Q. miranda .