Ceradocus baudini, Hughes, Lauren E., 2016

Hughes, Lauren E., 2016, New genera, species and records of Maeridae from Australian Waters: Austromaera, Ceradocus, Glossomaera, Hamimaera, Huonella gen. nov., Linguimaera and Maeraceterus gen. nov. (Crustacea: Amphipoda), Zootaxa 4115 (1), pp. 1-81 : 7-11

Ceradocus baudini sp. nov.

( Figs 2–6 )

Type material. Western Australia: Holotype female, 6 mm, dissected, 2 slides, AM P.92241, Beacon Island , Abrolhos Islands (28°25′30″S 113°47′00″E), 24 m, coral rubble covered in coralline algae, half way up reef front, 23 May 1992, coll. P.A. Hutchings (WA 501) ; paratype male, 6 mm, (left gnathopod the larger), AM P.79472, Beacon Island, Abrolhos Islands (28°25′30″S 113°47′00″E), 24 m, coral rubble covered in coralline algae, half way up reef front, 23 May 1992, coll. P.A. Hutchings (WA 501).

Additional material examined. Western Australia: 1 female, 6 mm, dissected, 4 slides, WAM C59000, Adele Island , The Kimberley , Western Australia (15°31′40″S 123°12′00″E) 13 October 2009, coll. Andrew Hosie (01/ K09-T1) ; 2 specimens, WAM C43732, Adele Island, The Kimberley (15°31′40″S 123°12′00″E) (01/K09-T1) ; 4 males, AM P. 97862, northern side of Malus Island, Dampier Archipelago (20°30.056′S 116°40.579′E), 8.7 m, mixed sponges, 27 August 1999, coll. R.A. Peart (WA 655) ; 1 male, AM P. 97863, east side of West Lewis Island, Dampier Archipelago (20°34.655′S 116°39.721′E), 5 m, from under rocks, 4 September 1999, coll. R.A. Peart (WA 709); 1 dissected specimen, 4 slides, NMV J46911 , north side of Cape Riche (34°37′00″S 118°47′00″E), 6 m, 14 April 1984 (SWA-47) ; 1 specimen, NMV J56984 , north side of Cape Riche (34°37′00″S 118°47′00″E), 6 m, 14 April 1984 (SWA-47).

Northern Territory: 1 specimen, 5.8 mm, dissected in part, 1 slide, AM P.78241, patch reef on north side of New Year Island (10°54′S 133°02′E), 10 m, coral rubble, 14 October 1982, coll. J.K. Lowry (NT 8).

Queensland: 1 a female, 5.5 mm, dissected, 4 slides, AM P.92239, northwest corner of Goodes Island, Torres Strait (10°33′35″S 142°09′09″E), 7.8 m, dead coral cf Tubipora musica , 29 September 2006, coll. M. Capa and L.E. Hughes (QLD 1874) ; 3 specimens, AM P.75599, northwest corner of Goodes Island, Torres Strait (10°33′35″S 142°09′09″E), 7.8 m, dead coral cf Tubipora musica , 29 September 2006, coll. M. Capa and L.E. Hughes (QLD 1874).

South Australia: 1 male, 9.2 mm, dissected, 4 slides, SAMA C6452, west of Aldinga, Gulf of St Vincent (33°16′00″S 138°26′59″E), 38–41 m, in prawn trawl, 8 May 1987, coll. K.L. Gowlett-Homes and S. Corigliano, FV Rivoli Queen ; 1 female, 8.4 mm, dissected, 4 slides, SAMA C8499, west of Aldinga , Gulf of St Vincent (33°16′00″S 138°26′59″E), 38–41 m, in prawn trawl, 8 May 1987, coll. K.L. Gowlett-Homes and S. Corigliano, FV Rivoli Queen ; 4 female and juvenile specimens, SAMA C8500, west of Aldinga , Gulf of St Vincent (33°16′00″S 138°26′59″E), 38–41 m, in prawn trawl, 8 May 1987, coll. K.L. Gowlett-Homes and S. Corigliano, FV Rivoli Queen .

Type locality. Beacon Island , Abrolhos Islands, Western Australia (28°25′30″S 113°47′00″E).

Etymology. Name in honour of the French Captain Nicolas Baudin, who named the type locality and was a notable collector of natural history specimens.

Description. Based on holotype female, 6 mm, AM P.92241.

Head. Eyes ovate to round; lateral cephalic lobe broad, apically rounded, anteroventral margin with notch/ slit, anteroventral corner acute. Antenna 1 longer than antenna 2; peduncular article 1 shorter than article 2, with 1 robust seta on posterior margin; peduncular article 2 longer than article 3; flagellum articles as long as broad, or broader than long, with 27 articles; accessory flagellum short, significantly less than half length of primary flagellum, with 5 articles. Antenna 2 peduncular article 4 longer than article 5; flagellum with 8 articles. Mandible (based on WAM C59000) accessory setal row, well developed with 7 setae; palp well developed, article 1 length subequal width, shorter than article 2, inner margin distally produced acute; article 2 much longer than article 3, with a many slender setae; article 3 reduced, 1.8 × as long as broad, subequal to article 1, with many slender setae. Lower lip without apical ducts, mandibular lobes apically rounded. Maxilla 1 inner plate with 6 slender setae.

Pereon. Gnathopod 1 coxa anterior margin concave, anteroventral corner produced, acute, posteroventral corner with notch; merus with posteroventral corner round; carpus length 2 × width, 0.9 × propodus length, margins lined with long setae, long setae covering medial surface; propodus subquadrate, medial surface setal comb absent, palm subacute, weakly convex, entire, lined with robust setae, defined by posterodistal corner with robust setae extending beyond palm; dactylus closing along palm, posterior margin lined with setules, unguis present.

Gnathopod 2 asymmetrical, subchelate; larger gnathopod coxa posteroventral corner without notch; basis slightly expanded, anterodistal corner subquadrate; merus with subquadrate posteroventral corner; carpus compressed, length 0.8 × width, margins with few slender setae; propodus rectilinear, length 1.6 × width, margin without setae, palm angle subacute, distal shelf with 3 pairs of robust setae, palm margin teeth with apical robust setae, with 1 subquadrate and 1 subacute tooth and defined by posteroventral corner with tooth and 1 robust seta; dactylus closing along palm, unguis present. Gnathopod 2 smaller gnathopod basis slightly expanded, anterodistal corner subquadrate; merus with acute posteroventral corner; carpus subtriangular, length 1.7 × width, posterior margin with long slender setae; propodus subovate to rectilinear, margins with rows of long slender setae, palm angle subacute, margin smooth, lined with robust setae defined by posteroventral corner with tooth and long robust seta; dactylus closing along and reaching end of palm, unguis present.

Pereopods 5–7 slender distally; basis posterior margin straight, weakly serrate; merus, carpus and propodus not broadened; dactylus unguis simple.

Pleon. Pleonites 1–3 dorsally serrate. Epimeron 1 posteroventral corner with acute tooth. Epimeron 2 ventral and posterior margin distally serrate, posteroventral corner with acute tooth. Epimeron 3 ventral and posterior margin serrate distally, posteroventral corner with acute tooth. Urosomites 1–2 strongly serrate. Uropod 1 peduncle with 1 basofacial seta, peduncle length 1.1 × outer ramus; inner ramus subequal to outer ramus. Uropod 2 peduncle length 1.1 × outer ramus; inner ramus longer than outer ramus. Uropod 3 (based on WAM C59000) based on rami subequal in length, longer than peduncle, length 4 × width, distally truncated, with lateral and apical long and short robust setae. Telson deeply cleft, length subequal to width, lobes divergent, tapering distally, with single apically acute cusps, each lobe with 1 short and 1 long apical robust setae, without marginal or lateral robust setae.

Variation. The asymmetrical gnathopod may be left or right dominant. The telson has two long robust setae in material from Abrolhos Island, while other South Australian, north Western Australia, Northern Territory and Queensland specimens have two long and 1 short robust setae. In AM P.97862 (WA 655), a 5.8 mm male had the form with large 2nd last tooth on male gnathopod 2 (figs 4, 5), and a 6.0 mm specimen had the terminal male gnathopod form where the 2nd last palm tooth is reduced (fig. 2). The specimens from cooler temperate waters in South Australia have a much larger body size, 9.2 mm, compared to material from all other locations ~ 5 mm.

Remarks. The distribution of C. baudini sp. nov. spans tropical Australia and ranges into temperate southern Australia. The gnathopod 2 propodus palm with a distal shelf, two palmar teeth and subacute palm defining tooth (4 teeth in total) identifies Ceradocus baudini sp. nov. and C. ramsayi (Haswell, 1880b) from other Ceradocus species. In Ceradocus baudini sp. nov. the dominant gnathopod 2 propodus palm angle is subacute while in C. ramsayi the palm is transverse.

Distribution. Australia. South Australia: Gulf of St Vincent. Western Australia: Abrohlos Islands, Adele Island, The Kimberley; Malus Island, West Lewis Island, Dampier Archipelago. Northern Territory: New Year Island. Queensland: Torres Strait (current study).

Figures

FIGURE 2. Ceradocus baudini sp. nov. female, habitus, 6.0 mm, AM P. 92241, Beacon Island, Abrolhos Islands, Western Australia.

FIGURE 3. Ceradocus baudini sp. nov. female, 6.0 mm, AM P. 92241, Beacon Island, Abrolhos Islands, Western Australia, scales 0.1 mm.

FIGURE 4. Ceradocus baudini sp. nov. female, 6.0 mm, AM P. 92241, Beacon Island, Abrolhos Islands, Western Australia, scales 0.1 mm.

FIGURE 5. Ceradocus baudini sp. nov., male habitus 6.0 mm, WAM C 59000, Adele Island, The Kimberley, Western Australia, scales 0.1 mm.

FIGURE 6. Ceradocus baudini sp. nov. female, habitus, 5.5 mm, AM P. 92239, Goodes Island, Torres Strait; ‘ n’ telson male, 5.8 mm, AM P. 78241, New Year Island, Northern Territory, scales 0.1 mm.