Dulichiella appendiculata ( Say, 1818 )

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 : 12-19

Dulichiella appendiculata ( Say, 1818)

( Figs 7–10)

Gammarus appendiculatus Say, 1818: 377 . – Bate, 1862: 223. – Della Valle, 1893: 765.

Melita appendiculata . – Stebbing, 1906: 428 (in part). – Feeley & Wass, 1971: 17. – Wass, 1972: 149. – Watling & Maurer, 1972: 262, tbls 5, 6. – Marsh, 1973: 90, tbl 1. – Ortiz, 1979a: 11. – Ortiz, 1979b: 15. – Sheridan, 1979: 70.

Melita dentata . – Pearse, 1912: 371 (according to Shoemaker, 1955 and LeCroy, 2000).

Melita fresneli . – Wass, 1965: 36.

Dulichiella appendiculata . – Karaman & Barnard, 1979: 153. – Barnard & Barnard, 1983: 668. – Ortiz & Lalana, 1993: 23. – LeCroy, 2000: 77, fig. 125.

Not Melita appendiculata . –J.L. Barnard, 1970: 161, figs 101–102 (= D. oahu sp. nov.). –J.L. Barnard, 1971: 85 (= D. oahu sp. nov.). – Hirayama & Kikuchi, 1979: 69, figs 2–6 (= D. tomioka sp. nov.). –Ischimaru, 1994: 49 (= D. tomioka sp. nov.).

Not Dulichiella appendiculata . – Ledoyer, 1979: 570, fig. 216 (= D. tulear sp. nov.). – Ledoyer, 1986: 185, fig. 8 (= D. terminos sp. nov.). – Ledoyer, 1986: 187, fig. 9 Mau (= D. cuvettensis Appadoo & Myers, 2005 ), fig. 9 S (= D. guinea sp. nov.). – Berents, 1983: 111, fig. 9 (= D. pacifica Lowry & Springthorpe, 2005 ). – Hirayama, 1986: 35, fig. 220 (map) (= D. tomioka sp. nov.). –Ischimaru, 1994: 49 (= D. tomioka sp. nov.). – Wakabara & Serejo, 1998: 574 (=? D. anisochir ( Krøyer, 1845)) .

Type material. Neotype male, 8.1 mm, USNM 1092318 , McQueen Inlet , Saint Catherines Island, Georgia, USA (31°38'06"N 81°08'06"W), R.W. Heard, 18 February 1991.

Type locality. McQueen Inlet , Saint Catherines Island, Georgia, USA (31°38'06"N 81°08'06"W) .

Additional material. Georgia: 1 female (ovigerous), 6.7 mm, USNM 1092319 , 42 specimens, USNM 1092320 . 40 specimens, AM P61182, McQueen Inlet, Saint Catherines Island , Georgia, USA, 31°38'06"N 081°08'06"W, R.W. Heard, 18 February 1991 .

Florida: Specimens, Indian River Lagoon, St. Lucie County (27°26.30' N, 80°18.00'W), USNM acc. # 318210, buoy 191, grass bed, Harbor Branch Indian River Survey, stn 41 R. Specimens , Pigeon Key , USNM acc # 162578, USFCS Fish Hawk, 20 December 1912 . Specimens , Battlepoint Key , Florida Bay , USNM acc. # 157628, (B.P. T.S. #4), wharf piling, R. P. Allen, 20 November 1939 . 1 ovigerous female, Bonita Beach, USNM Acc. # 161453. 25– 30 specimens, Lemon Bay , USNM acc. # 146660, Olga Hartman, January 1938 . Bird Key, Sarasota Bay , USNM Acc. # 167697, M.W. Williams, 8 May 1944 . Adult female, Tampa Bay , USNM #64746 , USFCS Albatross, 17 March 1885 . Alligator Harbor, about 40 miles south of Tallahassee , USNM acc. # 185296, from seaweed growing on bottom, about 1m depth, H.J. Humm, 22 October 1949 . 2 specimens (adult female, adult male) Crooked Island Sound, St. Joe , USNM acc. # 136942; eelgrass; A.S. Pearse, 21 November 1935 .

Louisiana: Cameron, USNM 33120, L. R. Cary (identified by Pearse, 1912 as Melita dentata ). Description. Based on neotype male, 8.1 mm, USNM 1092318, and female (ovigerous), 6.7 mm, USNM 1092319. Body large. Head eyes ovate; lateral cephalic lobe broad, truncated, anteroventral corner with slen- der seta. Antenna 1 peduncular article 1 shorter than article 2, with 3 robust setae along posterior margin. Antenna 2 peduncular article 2 cone gland reaching at least to end of peduncular article 3; article 4 slightly longer than article 5. Mandibular palp article 1 about as long as broad, inner margin article 1 not produced distally; article 2 slightly longer than article 3.

Gnathopod 1 coxa anteroventral corner not produced, anterior margin concave, posteroventral corner notch present; carpus subequal in length to propodus; propodus small, linear, palm slightly convex, palm defined by posterodistal corner, with posterodistal robust setae. Gnathopod 2 coxa posteroventral corner notch present; (larger) propodus distolateral crown with 4 rounded spines, fourth spine weak or occasionally absent, palm sinusoidal, posterodistal corner produced, upturned, posterodistal corner dactylus fitting into corner; dactylus apically blunt; (smaller) merus with sharp posteroventral spine; palm convex,

without robust setae, posterodistal corner with robust setae; dactylus with 1 or 2 setae on anterior margin. Pereopod 5 dactylar unguis anterior margin with 2 accessory spines. Pereopods 6–7 basis, merus, carpus and propodus with bunches of long slender setae. Pereopod 6 basis posterior margin straight; dactylar unguis anterior margin with 2 accessory spines. Pereopod 7 basis posterior margin straight.

Pleonite/urosomite dorsal spine formula (7-7-7-5-4-2). Pleonites 1–3 with 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 spine at midline, no conspicuous medial gape. Urosomite 2 with two groups of 1–3 small dorsolateral robust setae. Urosomite 3 with dorsal setae, with 2 dorsal spines. 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 convex; dactylus posterior margin smooth. Pereopod 7 basis expanded, posterior margin tapering distally.

Habitat. Marine epibenthic, polyhaline on sponges, hydroids and bryozoans ( Feeley & Wass, 1971; Wass, 1972).

Remarks. The distribution records from this species are based mainly on LeCroy (2000) and LeCroy (in litt.). As Shoemaker (1955: 50) points out (confirmed by LeCroy, 2000: 77) the record of Melita dentata of Pearse (1912) from Cameron, Louisiana is actually D. appendiculata .

The illustrations presented here (figs 7–10) agree with the illustrations of LeCroy (2000: fig. 125) except the number of spines on the male gnathopod 2 distolateral crown. LeCroy shows three spines and we show four. LeCroy did not count the first spine on the crown, which appears as a shelf, and her illustration does not show a fourth spine. In D. appendiculata the fourth spine is weakly developed or missing. We have illustrated a specimen with a weakly developed spine and in LeCroy’s specimen the spine is absent.

Dulichiella appendiculata has four spines on the distolateral crown of male gnathopod 2 (the fourth spine is not well developed) and a 7-7-7-5-4 pleonite/urosomite formula. Five other species share these character states: D. cuvettensis ; D. fresnelii ; D. guinea ; D. lecroyae ; and D. pacifica . Dulichiella appendiculata differs from all of these species, except D. guinea ; in having bunches of long slender setae on the basis, merus, carpus and propodus of male pereopods 6 and 7. However D. guinea has a very setose dorsal pleosome.

Dulichiella appendiculata and D. lecroyae have an overlapping distribution along the Florida coast. These species are similar, particularly in the distolateral crown, but they differ in the shape of the lateral cephalic lobe which is truncated in D. appendiculata (rounded in D. lecroyae ); the posterior-most spine (4) on the distolateral crown of male gnathopod 2 which is vestigial or absent in D. appendiculata (always well developed in D. lecroyae ); the palm of female gnathopod 2 which is convex in D. appendiculata (concave in D. lecroyae ); the dactyli of the pereopods which have two accessory spines in D. appendiculata (one in D. lecroyae ); and the posteroventral corners of epimera 1 and 2 which have small acutely produced corners in D. appendiculata (subquadrate in D. lecroyae ).

Dulichiella appendiculata can be separated from the Red Sea species, D. fresnelii , by the smooth posterior margin of the dactylus of female gnathopod 1 (crenulate in D. fresnelii ) and the short telson (longer in relation to its width in D. fresnelii ).

Dulichiella appendiculata can be distinguished from the Indo Pacific species D. cuvettensis and D. pacifica as follows. Dulichiella cuvettensis has a longer mandibular palp article 3, the pereopods have only one accessory spine each on the dactyli and in the male there are no bunches of long slender setae on pereopods 6 and 7. Dulichiella pacifica has an undefined, rounded posterodistal corner on the palm of male gnathopod 1 (defined, subquadrate in D. appendiculata ), male pereopods 6 and 7 with bunches of long, slender setae only on the carpus and propodus (basis, merus, carpus and propodus in D. appendiculata ), pereopods 5 to 7 with one accessory spine each on the dactyli (2 in D. appendiculata ) and the telson is longer than broad (as long as broad in D. appendiculata ).

LeCroy (2000) indicated a possible third species of Dulichiella in the south-eastern United States, living in “high salinity grass and algal beds of south Florida and St. Joe Bay on the Florida panhandle”. These specimens have a small fourth spine on the distolateral crown of the male second gnathopod, fewer setae than usual on the basis of pereopods 6 and 7 and a somewhat flatter palm on the female second gnathopod. These characteristics fall within the range of variation for D. appendiculata .

Distribution. USA. Delaware: Delaware Bay ( Watling & Maurer, 1972, unconfirmed). Virginia: Chesapeake Bay ( Wass, 1965, 1972; Feeley & Wass, 1971, unconfirmed). South Carolina: Sewee Bay (SERTC). Georgia: McQueen Inlet, Saint Catherines Island. Florida: Indian River Lagoon; Battlepoint Key, Florida Bay; Bonita Beach; Lemon Bay; Bird Key, Sarasota Bay; Tampa Bay; Alligator Harbor; Crooked Island Sound (all USNM); St. George Basin and Apalachicola Estuary, north-western Florida ( Sheridan, 1979). Louisiana: Cameron ( Pearse, 1912).