Cymadusa botulus, Hughes, Lauren E. & Peart, Rachael A., 2013

Hughes, Lauren E. & Peart, Rachael A., 2013, New species and new records of Ampithoidae (Peracarida: Amphipoda) from Australian Waters, Zootaxa 3719 (1), pp. 1-102 : 24-28

Cymadusa botulus sp. nov.

( Figs. 12 , 13 )

Type material. Holotype male, 13.0 mm, dissected, 4 slides, WAM C52210, Woodman Point, Western Australia (32°08’S 115°44’E), depth unknown, 20 August 1997, coll. D. Mead-Hunter; paratypes 3 males, WAM C52211, Woodman Point (32°08’S 115°44’E), depth unknown, 20 August 1997, coll. D. Mead-Hunter; paratypes 2 males, AM P.79483, Woodman Point (32°08’S 115°44’E), depth unknown, 20 August 1997, coll. D. Mead-Hunter.

Additional material examined. Western Australia: 9 specimens, AM P.88412, Marmion, (31°50’S 115°45’E), 0.5 m, in seagrass Amphibolis sp., 7 July 2011, coll. A.G.B. Poore.

Tasmania: Male, AM P.83632, beach between Pelican Point and Blanche Point, Georges Bay (41°17’11”S 148°19’36”E), 0–1 m, tufted brown alga and green alga Ulva sp. on sandy bottom, 13 April 1991, coll. J.K. Lowry and S.J. Keable (Tas 120); 3 specimens, AM P.83633, Clerk Point, Georges Bay (41°17’S 148°19’30”E), 0.5 m, seagrass Heterozostera sp., 12 April 1991, coll. P.B. Berents and R.T. Springthorpe (Tas 107); male, AM P.88429, Burnie (41°3’S 145°54’E), depth unknown, 22 February 2003, coll. Aquenal.

Type locality. Woodman Point, Western Australia (32°08’S 115°44’E).

Etymology. Botulus , Latin for sausage, in reference to the shape of the expanded antenna 1 peduncle, applied as a noun in apposition.

Diagnosis. Antenna 1 peduncular article 1 ventral margin with 4 robust setae; accessory flagellum 4-articulate. Antenna 2 robust, distinctly stouter than antenna 1; peduncle article 4 subequal in length to article 5, articles expanded, with scattered robust setae; flagellum incomplete with more than 18 articles. Mandible accessory setal row with 11 setae. Maxilla 1 inner plate with 6 slender setae; outer plate palp article 2 with 10 robust setae. Gnathopod 1 coxa 1 distinctly larger than coxa 2, anterior margin concave, anteroventral corner produced, subacute; basis anterodistal corner without well-developed lobes; ischium anterior margin without well-developed lobes; propodus subtriangular, palm subacute, straight, defined by rounded corner with 1 robust seta. Gnathopod 2 basis anterodistal corner rounded without well-developed lobe; ischium anterior margin bilobate; carpus cupshaped, length 0.9 times width; propodus subovoid, length 1.5 times width, palm subacute, entire with rounded distal tooth near base of dactylus, defined by subacute tooth and subquadrate corner, posterior postpalmar margin with 1 robust seta; dactylus much shorter than palm, apically broad to subacute, tapering evenly, inner margin smooth. Epimeron 1 rounded. Epimera 1–3 subquadrate, posteroventral corner rounded. Telson apically rounded with 4 pairs of lateral slender setae and 1 pair of apical setae.

Description of holotype. Head. Antenna 1 peduncular article 1 subequal to article 2, ventral margin with 4 robust setae; article 2 length 3 times than article 3; primary flagellum, with 33 articles; accessory flagellum 4- articulate. Antenna 2 robust, distinctly stouter than antenna 1; peduncle article 4 subequal in length to article 5, articles expanded, with scattered robust setae; flagellum incomplete with more than 18 articles. Mandible accessory setal row with 11 setae; palp 3-articulate; article 2 with 3 slender setae; article 3 length 3 times width. Lower lip outer plates with slit; lateral lobes much longer than medial lobes apical ducts absent, mandibular lobes with curved margins, rounded apically. Maxilla 1 inner plate with 6 slender setae; outer plate palp broad, article 2 with 10 robust setae.

Pereon. Coxae 1–4 longer than broad. Gnathopod 1 smaller than gnathopod 2; coxa 1 distinctly larger than coxa 2, anterior margin concave, anteroventral corner produced, subacute; basis subequal in length to coxa, posterior margin without setae, anteroventral corner rounded, without well-developed lobes; ischium anterior margin without well-developed lobes; merus posterodistal corners produced acute; carpus subtriangular, length 1.75 times width, subequal in length to propodus, posterior margin truncated; propodus subtriangular,1.8 times width, palm subacute, straight, defined by rounded corner with 1 robust seta, palm length 0.5 times posterior margin; dactylus subequal in length to palm, apically acute, tapering evenly, inner margin crenate. Gnathopod 2 sexually dimorphic; basis anterodistal corner rounded without well-developed lobe; ischium anterior margin bilobate; merus margin with reduced lobe; merus posteroventral corner rounded; carpus cup-shaped, length 0.9 times width, 0.25 times propodus length; propodus subovoid, length 1.5 times width, palm subacute, entire with rounded distal tooth near base of dactylus, defined by subacute tooth and subquadrate corner, palm length 0.5 times posterior margin, posterior postpalmar margin with 1 robust seta; dactylus much shorter than palm, apically broad to subacute, tapering evenly, inner margin smooth.

Pleon. Epimeron 1 rounded. Epimera 1–3 subquadrate, posteroventral corner rounded. Uropod 1 long, reaching past uropod 2 rami; peduncle with 9 robust setae with large, acute distoventral spine, length 3.8 times width; inner ramus length 0.8 times peduncle, longer than outer ramus, with 2 marginal robust setae; outer ramus slender with 5 marginal robust setae. Uropod 2 peduncle with 5 robust setae, distoventral spine absent; inner ramus with 6 marginal robust setae; outer ramus subequal in length to inner ramus with 7 marginal robust setae. Uropod 3 peduncle length 1.9 times longer than broad, 2.8 times rami length, with 9 marginal robust setae, 3 distal robust setae, and 1 distal slender seta; inner ramus length 0.3 times peduncle, with 2 distal robust setae, 3 distal slender setae and 3 lateral robust setae; outer ramus shorter than inner ramus, with 2 large recurved distal robust setae and 1 lateral robust seta. Telson subtrapezoidal, apically rounded, with small apical cusps, 4 pairs of lateral slender setae, 2 pairs of lateral plumose setae and 1 pair of apical setae.

Remarks. Cymadusa botulus sp. nov. is the first record of an ampithoid species with antennae 2 peduncular articles 4 and 5 distally expanded. The male gnathopod 2 with a subovate propodus, palm with well-developed shelf and short dactylus is similar to C. smilodonta , C. imbroglio and C. priscileo sp. nov. Cymadusa botulus sp. nov. differs from these species in having a gnathopod 2 propodus palm that is defined by a broad subacute tooth and a recurved, evenly tapering dactylus. In C. smilodonta the gnathopod 2 propodus palm is defined by a corner without a tooth and a falcate dactylus.

Distribution. Australia. Western Australia: Woodman Point (current study). Tasmania: Georges Bay (current study).

Figures

FIGURE 12. Cymadusa botulus sp. nov., holotype male, 13.0 mm, WAM C 52210, Woodman Point, Western Australia.

FIGURE 13. Cymadusa botulus sp. nov., holotype male, 13.0 mm, WAM C 52210, Woodman Point, Western Australia, scales 0.1 mm.