Ampelisca flabellicaudata, Valério-Berardo, Maria Teresa & -, Yoko Wakabara, 2006

Valério-Berardo, Maria Teresa & -, Yoko Wakabara, 2006, Ampeliscidae from the Brazilian coast. Record of Ampelisca burkey Barnard & Thomas, 1989 and descriptions of two new species of Ampelisca (Crustacea, Amphipoda), Zootaxa 1286, pp. 1-14 : 3-8

Ampelisca flabellicaudata sp. nov.

Figs. 2–4

Material examined: holotype, female, 4.8mm, 23º47’S – 44º20’W, 98 m, mud and broken shell, R/V W. Besnard col., 10/05/70, MZUSP 16844. Paratypes: 23º 47’S – 44°20’ W, 98 m, mud and broken shell, R/V W. Besnard col., 10/05/70, MZUSP 16845, 2 specimens; 23º 14’S – 44° 03’W, 52 m, R/V W. Besnard col., 03/06/71 MNRJ 19651, 2 specimens; 23° 25’S – 43° 00’W, 113m, gravel and broken shell, R/V W. Besnard col., 02/09/70, MNRJ 19652, 2 specimens.

Etymology: The specific name is derived from the Latin flabelli fan and caudata posterior region. It refers to uropod 3 outer ramus broad, opened as a fan.

Diagnosis: Head with antero­ventral and antero­dorsal margins parallel. Antenna 1 shorter than antenna 2 peduncle. Antenna 2 long, extending to the body length. Coxa 1 with a notch on postero­ventral corner. Pereopod 7 basis expanded to end of merus, posterior margin oblique, propodus subequal to carpus in length, stout 1.3X longer than wide; dactylus subequal to propodus in length. Urosomite 1 produced and pointed dorsally. Uropod 1 peduncle shorter than rami, outer ramus without robust setae. Uropod 3 with broad rami, outer ramus enlarged as a fan, apical margin serrate with long plumose setae; inner ramus slightly longer than outer ramus. Telson apices lobes notched at apex.

Description: Holotype, female 4.5 mm. Head subequal in length to first 3 body segments. Antero­ventral and antero­dorsal margins of head parallel and ventral margin oblique to half of the medium posterior part of the head. Ventral pair of eyes at antero­ ventral corner of the head. Antenna 1 shorter than antenna 2 peduncle, peduncular article 2 slightly longer than article 1, without setae on ventral margin, flagellum with 5–7 articles, subequal in length of peduncle. Antenna 2 long extending to body length, peduncular article 4 longer than 5,flagellum with 25–30 articles. Left mandible with 5 accessory blades, mandibular palp article 2 elongate, not inflated with long setae in the inner margin, outer margin with 1 long plumose seta on distal corner, article 3 length 0.8 of article 2, with 3 medial setae and 3 apical setae. Maxilla 1 inner plate with two apical plumose setae, outer plate with 10 setal­teeth, palp article 2 provided with 2 distal cusps accompanied by 6 robust setae. Maxilliped inner lobe rectangular distally with subapical and apical rows of plumose setae, outer lobe reaching end of palp article 2 bearing 7 chisel­shaped robust setae along medial margin, and 5 apical robust setae; palp normal for the genus, article 3 clavate. Upper lip, lower lip and maxilla 2 with basic characters for the genus.

Coxae 1–4 longer than broad. Coxa 1 with a notch on postero­ventral corner, with marginal and submarginal rows of plumose setae. Coxa 2 with row of simple setae on ventral margin. Gnathopod 1 shorter and stouter than gnathopod 2. Gnathopod 1 basis slightly inflated distally with one row of simple setae on both margins; ischium and merus with setae on posterior margin; carpus 1,2X propodus length, both posterior margins with short plumose setae and simple setae; dactylus slightly curved, with 3 setules along inferior margin. Gnathopod 2 basis inflated distally with few long setae on both margins; carpus elongate about 1,6X propodus length, both with elongate simple setae on posterior margin; dacylus short with 4 plumose setules on inferior margin. Pereopods 3 and 4 similar in shape but the fourth is more massive and setose than third pereopod, both with dactylus elongate, slightly longer than propodus and carpus combined. Pereopod 3 merus with plumose setae along ¾ of posterior margin. Pereopod 4 basis and merus both margins with long plumose setae, merus about 3X as long as broad. Pereopod 5 basis subquadrate, anterior margin with plumose setae; carpus slightly longer than propodus produced posterodistally and bearing 5 robust setae on apex, posterior margin with one set of comb robust setae; dactylus short and trifurcate. Pereopod 6 with basis subquadrate, anterior margin with 4–5 short plumose setae and simple setae; carpus longer than propodus with 4 robust setae on postero­distal margin, posterior margin with 2 sets of robust setae; dactylus short and bifurcate. Pereopod 7 basis posterior margin oblique and with plumose setae, reaching middle of carpus; isquium length subequal to merus; merus posteror­distal lobe 1/3 length of carpus with several long plumose setae; carpus longer than merus, postero­distal corner not produced with 3 robust setae and 2 plumose setae, antero­ventral margin with 2 setae; propodus subequal to carpus in length, stout 1.3X longer than wide; dactylus curved anterodistally, shorter than propodus.

Epimeron 3 postero­ventral corner rounded. Urosomite 1 dorsally produced and acute. Uropod 1 slightly exceeding uropod 2 length; peduncle slightly shorter than rami, each margin with 2 robust setae; rami subequal in length, inner ramus with 3 robust setae on anterior margin; outer ramus without robust setae. Uropod 2 peduncle longer than rami; rami subequal in length, both inner margins of rami with robust setae; outer ramus with a long distal robust setae. Uropod 3 peduncle short with 2 dorsal robust setae outer ramus broader and shorter than inner ramus, distal margin enlarged as a fan and serrated with a long plumose seta between each serration, inner ramus slightly longer than outer ramus, with distal plumose setae along inner margin. Telson cleft 0.6X length with 2–3 pair of dorsal robust setae, apices lobes notched, each notch bearing 1 seta and 1 robust seta.

Remarks: Ampelisca flabellicaudata sp. nov. is closely related to A. pacifica Holmes, 1908 , A. cristata Holmes, 1908 and A. parapacifica Goeke & Heard,1984, in having the broad uropod 3 outer ramus, head with antero­dorsal and antero­ventral margins parallel and short antenna1. Ampelisca flabellicaudata can be distinguished from those species by epimera 3 postero­ventral corner rounded without tooth. In addition Ampelisca flabellicaudata sp. nov differs from A. pacifica and A. parapacifica by the stout propodus of pereopod 7, about 1.3X longer than wide. Ampelisca flabellicaudata sp. nov. also differs from A. cristata by the pointed carina on urosomite 1, instead of a large rounded laminar carina characteristic of A. cristata , uropod 1 peduncle shorter than rami and pereopod 7 carpus subequal to propodus in length instead of propodus longer than carpus in A. cristata .

Another species with broad uropod 3 outer ramus are Ampelisca dentifer (sensu Schellenberg, 1931), A. statenensis Barnard, 1932 , A. miharaensis Nagata, 1959 , A. hessleri Dickinson, 1982 and A. bidura Lowry & Poore,1985 . Ampelisca flabellicaudata sp. nov. differs from all those species by head with antero­ventral and antero­dorsal margins parallel. In addition Ampelisca flabellicaudata sp. nov. differs from A. dentifer , A. statenensis and A. miharaensis by epimera 3 postero­ventral corner without tooth. Ampelisca flabellicaudata sp. nov. can be distinguished from A. hessleri and A. bidura in lacking a row of robust setae along margins of cleft telson.

Figures

FIGURE 2. Ampelisca flabellicaudata sp. nov.: female, 4.8 mm, holotype. MZUSP 16844

FIGURE 3. Ampelisca flabellicaudata sp. nov.: female, 4.8 mm, holotype. MZUSP 16844.

FIGURE 4. Ampelisca flabellicaudata sp. nov.: female, 4.8 mm, holotype. MZUSP 16844.