Ceradocus circe Lowry & Springthorpe, 2005, n.sp.
Creators: name: Lowry, JK
name: Springthorpe, RT
Publisher: name: Zenodo
Year: 2005
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Malacostraca
Amphipoda
Maeridae
Ceradocus
Ceradocus circe

description: Ceradocus circe n.sp.
Figs. 5–7
Ceradocus rubromaculatus.–Chilton, 1921b: 71, fig. 9a–c.
Type material. HOLOTYPE ♂ “a”, 24.3 mm, AM P60564; 1 PARATYPE, ♀ “a”, 18.6 mm, AM P60565; 1 PARATYPE, ♂ “b”, 22.9 mm, AM P 5915; 8 Paratypes, AM E6543, 16 kms north of Circular Head, Tasmania, Australia, [approx. 40°46'S 145°18'E], FIS Endeavour, 1909–1914. 1 PARATYPE, female, AM E6542, Tasmanian Coast, Australia, FIS Endeavour, 1909–1914
Type locality. 16 kms north of Circular Head, Tasmania, Australia, [approx. 40°46' S 145°18'E].
Description. Based on holotype ♂ “a”,AM P60564, paratype ♀ “a”, AM P60565, and paratype ♂ “b”, AM P5915.
Head. Lateral cephalic lobes broad, rounded, with anteroventral notch or slit, anteroventral corner with acute/ subacute spine. Antenna 1 longer than antenna 2; peduncular article 1 subequal in length to article 2, with 4 or more robust setae along posterior margin; flagellum with at least 30 articles; accessory flagellum with 11 articles. Antenna 2 peduncular article 2 cone gland not reaching to end of peduncular article 3; article 4 subequal to article 5; flagellum with about 20 articles. Mandible palp article 3 cone-like, setose on distomedial margin, subequal to article 1; article 2 longer than article 3; article 1 produced distally, shorter than article 2, about as long as broad. Maxilla 1 inner plate setose along entire inner margin.
Pereon. Gnathopod 1 coxa anteroventral corner produced, acute, posteroventral corner notch absent; merus with sharp posterodistal spine; propodus palm acute, straight, defined by posterodistal corner, defined by posterodistal robust setae. Gnathopod 2 sexually dimorphic; subchelate; coxa posteroventral corner notch absent; merus with sharp posteroventral spine; 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 spine; apically acute/subacute. Pereopod 5 basis posterior margin straight, posteroventral corner narrowly rounded or subquadrate. Pereopod 6 coxa anterior lobe ventral margin slightly produced, rounded; basis posterior margin straight, posteroventral corner with acute or subacute process. Pereopod 7 basis posterior margin straight, posteroventral corner with acute or subacute process.
Pleon. Pleonites 1–3 with dorsal serrations. Epimeron 1 posteroventral corner with small acute 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 with dorsal serrations, with spines at midline, no conspicuous medial gape. Urosomite 2 posterior margin serrate. Uropod 3 inner ramus subequal in length to outer ramus; outer ramus much longer (more than 2× length) than peduncle; 1-articulate. Telson each lobe with 3 or more apical/subapical robust setae, apical conical extension reaching at least halfway along longest seta.
Female (sexually dimorphic characters). Gnathopod 2 convex, smooth, without robust setae, defined by posterodistal robust setae, defined by posterodistal spine.
Habitat. Marine; continental shelf.
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, Tasmania.
Remarks. Among Australian species of Ceradocus, C. circe occurs in the group with sparse serrations along the posterior margins of epimera 1 and 2. Within this group C. circe appears to be the only species with the rami of uropod 3 more than twice as long as the peduncle (not known for C. yandala Berents, 1983 from tropical northeastern Australia).
Ceradocus orchestiipes A. Costa, 1853 from the Mediterranean Sea, has sparse serrations along the posterior margins of epimera 1 and 2, long rami on uropod 3 and the second gnathopods in the male and the female are very similar to those of C. circe. But C. orchestiipes does not have dorsal serrations on urosomites 1–3, nor does it have a strongly serrate posterodistal corner on epimeron 3.
Distribution. Tasmania: north of Circular Head; eastern slope of Bass Strait (Chilton, 1921b).
Australian geographic areas. Southeastern Australia.
description: Published as part of Lowry, JK & Springthorpe, RT, 2005, New and Little-known Melitid Amphipods from Australian Waters (Crustacea: Amphipoda: Melitidae), pp. 237-302 in Records of the Australian Museum 57 on pages 244-246, DOI: 10.3853/j.0067-1975.57.2005.1463, http://zenodo.org/record/15323482