Dulichiella fresnelii ( Audouin, 1826 )

Published, First, 2007, A revision of the tropical / temperate amphipod genus Dulichiella Stout, 1912, and the description of a new Atlantic genus Verdeia gen. nov. (Crustacea: Amphipoda: Melitidae), Zootaxa 1424, pp. 1-62 : 27-31

Dulichiella fresnelii ( Audouin, 1826)

( Figs 19–22)

Gammarus fresnelii Audouin, 1826: 93 , pl. 11, fig. 3.

Amphithoe fresnelii . –H. Milne Edwards, 1830: 377. –H. Milne Edwards, 1840: 38.

Paramoera fresnelii . – Miers, 1875: 75.

Melita fresnelii . – Della Valle, 1893: 708 (in part) (not pl. 60, fig. 6 copy of gnathopod 2 of M. anisochir Krøyer, 1845 ). – Spandl, 1924: 53, fig. 19

Dulichiella fresneli . – Karaman & Barnard, 1979: 153. – Barnard & Barnard, 1983: 668 (in part = D. cotesi ( Giles, 1890) , D. anisochir Krøyer, 1845 ). – Irie & Nagata, 1962: 19 (= D. tomioka sp. nov.).

Not Melita fresneli . –J.L. Barnard, 1955: 13 (= D. oahu sp. nov.).

Not Melita fresnelii . – Stebbing, 1910: 596–597, 642 (= D. australis ( Haswell, 1879)) . – Kunkel, 1910: 31, fig. 11 (= D. lecroyae sp. nov.). – Pearse, 1912: 371 (= D. lecroyae sp. nov., LeCroy, pers. comm.). – Chilton, 1921: 70 (= D. australis ( Haswell, 1879) . – Hale, 1927: 314 (= D. australis ( Haswell, 1879) . – Shoemaker, 1941: 187 (= D. spinosa Stout, 1912 ). – Nagata, 1964: 9 (= D. tomioka sp. nov.).

Type material. Neotype male, 6.6 mm, NHMW 19616 , Little Bitter Lake , Suez Canal, Egypt, Engl. Zool. Suez-Kanal Expedition, 17 October 1924.

Type locality. Little Bitter Lake , Suez Canal, Egypt (approx. 30°20'N 32°20'E) .

Additional material. 1 female, 6.7 mm, NHMW 20944 , 8 males, 15 females, NHMW 20945 , Little Bitter Lake , Suez Canal, Egypt . 3 specimens NMHW 19617 , Le Cap, Engl. Zool. Suez-Kanal Expedition, 24 Dec 1924 .

Description. Based on neotype male, 6.6 mm, NHMW 19616 and female, 6.7 mm, NHMW 20944. Body large. Head eyes round; lateral cephalic lobe broad, truncated, anteroventral corner with slender setae. Antenna 1 peduncular article 1 shorter than article 2, with 4 robust seta on posterior margin. Antenna 2 peduncular article 2 cone gland not reaching to end of peduncular article 3; article 4 longer than article 5. Mandibular palp article 1 about as long as broad, inner margin article 1 not produced distally; article 2 subequal to article 3.

Gnathopod 1 coxa anteroventral corner not produced, anterior margin concave, posteroventral corner notch present; carpus longer than propodus; propodus "stout", palm straight, palm defined by posterodistal corner, with posterodistal robust setae. Gnathopod 2 coxa posteroventral corner notch present; (larger) propodus distolateral crown with 4 rounded or subacute spines, fourth spine well developed, palm sinusoidal, posterodistal corner produced, upturned, dactylus overlapping corner; dactylus apically hooked; (smaller) merus with sharp posteroventral spine; palm slightly convex, without robust setae, posterodistal corner with robust setae; dactylus with more than 2 setae on anterior margin. Pereopod 5 dactylar unguis anterior margin with 2 accessory spines. Pereopods 6–7 carpus and propodus with bunches of long slender setae. Pereopods 6–7 carpus and propodus with bunches of long slender setae. Pereopod 6 basis posterior margin straight; dactylar unguis anterior margin with one accessory spine. Pereopod 7 basis posterior margin tapering distally.

Pleonite/urosomite dorsal spine formula (7-7-7-5-4-2). Pleonites 1–3 with sparse dorsal setae.

Epimeron 1 posteroventral corner with small acute or subacute spine. Epimeron 2 posteroventral corner acute. Epimeron 3 posteroventral margin smooth. Urosomite 1 with three dorsal spines. Urosomite 2 with two groups of 1–3 small dorsolateral robust setae. Urosomite 3 without dorsal setae. Uropod 3 outer ramus very long, about 2 x peduncle. Telson with dorsal robust setae.

Female (sexually dimorphic characters). Gnathopod 2 subequal in size, similar to smaller gnathopod 2 of male; palm slightly sinusoidal; dactylus posterior margin crenulate. Pereopod 7 basis expanded, posterior margin slightly convex, tapering distally.

Habitat. Marine epibenthic.

Remarks. Many collections have been misidentified as D. fresnelii , mainly because of the indiscriminate synonymy of Della Valle (1893). In the text of Audouin (1826) there are no diagnostic characters to distinguish D. fresnelii and the type material of the species is no longer extant. The type locality as given by Audouin (1826) is Egypt. It is almost certainly from the Red Sea, because exhaustive collecting in the Mediterranean Sea has never turned up a species of Dulichiella (see Karaman, 1982).

The original illustrations of D. fresnelii are too general to distinguish it as a particular species. Spandl (1924) had at least one male of a Dulichiella from the Red Sea, which he called Melita fresnelii . He illustrated the proximal ends of the first and second antennae, the distal end of a male gnathopod 2 and the dorsum of pleonites 1 to 3 and urosomite 1, but these illustrations are not enough to identify the species. This is also true for the Nayar’s (1959; 1966) records of D. fresnelii from the east coast of India.

We have redescribed other material from Spandl’s Suez Canal collection and established a neotype. Based on the four-spined distolateral crown of male gnathopod 2 and the 7-7-7-5-4-2 pleonite/urosomite formula D. fresnelii is most similar to the Atlantic species D. appendiculata and D. lecroyae and the Indo Pacific species D. cuvettensis and D. pacifica .

Dulichiella fresnelii has a slightly convex palm on the female gnathopod 2 which is similar to that of D. appendiculata , but the sexually dimorphic male pereopods 6 and 7 are much less setose in D. fresnelii . Dulichiella lecroyae differs mainly in the lateral cephalic lobe which is apically rounded (apically truncated in D. fresnelii ) and the posterior margin of the female pereopod 7 basis which is convex (straight and tapering distally in D. fresnelii ).

Dulichiella fresnelii and D. cuvettensis appear to be very similar. However D. fresnelii has only one accessory spine on the dactyli of pereopods 5 to 7 (two accessory spines in D. cuvettensis ) and the male of D. fresnelii has bunches of long, slender setae on the carpus and propodus of pereopods 6 and 7 which are lacking on the pereopods of D. cuvettensis . Dulichiella fresnelii and D. pacifica also appear to be very similar, but D. fresnelii has a straight posterior margin on the basis of male pereopod 6 (concave in D. pacifica ). and a straight posterior margin on the basis of female pereopod 7 (concave in D. pacifica ).

Distribution. Red Sea.