Australian Amphipoda: Melitae

J.K. Lowry, P.B Berents & R.T. Springthorpe

Ceradocus circe Lowry & Springthorpe

Ceradocus rubromaculatus. --Chilton, 1921: 71, fig. 9a-c.

Type material. HOLOTYPE: male"a", 24.3 mm, AM P60564. PARATYPES: female, 18.6 mm, AM P60565; male"b", 22.9 mm, AM P5915; female, AM E6542; 8 specimens, AM E6543.

Type locality. 16 kms north of Circular Head, Tasmania (40º46'S 145º18'E).

Description. Based on holotype male "a", AM P60564, paratype female "a", AM P60565, and paratype male "b", AM P5915. Head with anteroventral notch or slit, anteroventral corner with acute/subacute tooth. Antenna 1 longer than antenna 2; peduncular article 1 not geniculate with article 2, subequal in length to article 2, with 4 or more robust setae along posterior margin; accessory flagellum with 10 articles (about). Antenna 2 peduncular article 2 cone gland reaching at least to end of peduncular article 3; article 4 subequal to article 5. Mandible palp present, well developed, article 3 cone-like, subequal to article 1, article 2 longer than article 3, article 1 produced distally, shorter than article 2, about as long as broad.

Pereon. Gnathopod 1 not sexually dimorphic; coxa anteroventral corner produced, acute, coxa posteroventral corner notch absent; merus with sharp posterodistal tooth; carpus about 2 x as long as broad; propodus without anterodistal projection, posterodistal margin not swollen, palm acute, straight, defined by posterodistal corner, defined by posterodistal robust setae. Gnathopod 2 sexually dimorphic; subchelate; left and right gnathopods subequal in size; coxa posteroventral corner notch absent; merus with sharp posteroventral tooth; carpus compressed; propodus without medial depression, without strong concentration of setae, palm acute, straight, sculptured, with group of anterodistal robust setae, without posterodistal robust setae, defined by posteroventral tooth; dactylus closing along palm, reaching end of palm, apically acute/subacute. Peraeopod 5 basis posterior margin straight. Peraeopod 5 basis posteroventral corner narrowly rounded or subquadrate. Peraeopod 6 coxa anterior lobe ventral margin not produced ventrally. Peraeopod 6 basis posterior margin straight. Peraeopod 6 basis posteroventral corner with acute or subacute process. Peraeopod 6 propodus not expanded posterodistally. Peraeopod 7 basis posterior margin straight. Peraeopod 7 basis with posterior margin smooth or minutely castelloserrate, posteroventral corner with acute or subacute process. Peraeopod 7 propodus not expanded posterodistally.

Pleon. Pleonite 1 with dorsal serrations, without dorsodistal spines, not dorsally bicarinate. Pleonite 2 with dorsal serrations, without dorsodistal spines, not dorsally bicarinate. Pleonite 3 with dorsal serrations, without dorsodistal spines, dorsally smooth. Epimeron 1 anteroventral corner without curved spine. Epimera 1-2 posteroventral margin with 3 large or small spines above spine defining posteroventral corner, or without spines above posteroventral corner. Epimeron 3 posterior margin serrate, posteroventral corner with strongly produced acute spine, posteroventral margin serrate. Urosomite 1 without dorsal carina, without a small dorsal hump, with dorsal serrations, with spines at midline, no conspicuous medial gape, not dorsally bicarinate. Urosomite 1 without posterodorsal spine. Urosomite 2 posterior margin serrate, without dorsolateral robust setae. Urosomite 3 without dorsal robust setae. Uropod 1 peduncle with basofacial robust seta, without distoventral spur. Uropod 3 greatly exceeding uropods 1 and 2; inner ramus subequal in length to outer ramus; outer ramus long (more than 1.6 x longer than peduncle), 1-articulate. Telson cleft. Telson without robust setae on inner margins. Telson each lobe with 3 or more apical/subapical robust setae, apical conical extension reaching at least halfway along longest seta.

Habitat. Marine.

Etymology Named for the wooden schooner Circe, which went ashore in 1892, between Entrance Island and the North Spit while attempting to pass through Hells Gates and enter Macquarie Harbour, Strahan, Tasmania.

Remarks. Similar to Ceradocus orchestiipes A. Costa, 1853 from the Mediterranean Sea.

Distribution. Tasmania: north of Circular Head (Chilton, 1921); eastern slope of Bass Strait (Chilton, 1921).

Australian geographic areas. South-eastern Australia.

(Variant) Female (sexually dimorphic characters).

Pereon. Gnathopod 2 convex, smooth, without robust setae, without posteroventral corner.

Cite this publication as: 'J.K. Lowry, P.B Berents & R.T. Springthorpe (2000 onwards). Australian Amphipoda: Melitae Descriptions, Illustrations, Identification and Information Retrieval. Version: 2 October 2000.'.