Cymadusa tattersalli, Peart, 2004

Peart, R. A., 2004, A revision of the Cymadusa filosa complex (Crustacea: Amphipoda: Corophioidea: Ampithoidae), Journal of Natural History 38 (3), pp. 301-336 : 314-319

Cymadusa tattersalli n. sp.

(figures 8–11)

Grubia setosa Tattersall, 1922: 1–19 .

Cymadusa filosa: Ledoyer, 1982: 130–135 , figures 44–46 (form A).

Type material. HOLOTYPE: male, 17 mm length, TMAG G3932, Woodman Point , Cockburn Sound, Western Australia, Australia, 32°08∞S, 115°45∞E, 14 July 1973, T. M. Walker and D. D. Bray . PARATYPES: TMAG G3931 (female), AM P51282 (female and male); TMAG G3933 (male); TMAG G3934-G3938 (females and males—five specimens), collection data is the same as that of the holotype .

Type locality. Cockburn Sound , Western Australia, Australia .

Diagnosis. Antenna 1 with a two-articulate accessory flagellum. Antenna 2 with densely plumose setose margins. Gnathopod 1 with densely plumose setose margins; merus slightly produced to form a small, rounded, anteroventral lobe; carpus robust, broad and subtriangular. Gnathopod 2 with densely plumose setose margins; propodal palm with defining posterodistal, small and subacute tooth, with subquadrate mid-palmar tooth; dactylus shorter than palm.

Description

Based on holotype male, 17 mm.

Head. Antenna 1 longer than antenna 2; peduncular article 1 subequal to article 2, article 2 longer than article 3, article 3 shorter than article 1; primary flagellum with 46 articles; accessory flagellum with two articles. Antenna 2 with dense, plumose setae on ventral margin; peduncular article 4 subequal to article 5. Upper lip entire; distal setae present. Lower lip outer plate, outer lobe longer than inner lobe. Mandible with nine robust setae in setal row; palp article 1 shorter than article 2, article 2 subequal to article 3, article 3 longer than article 1, setae on posterior margin and apex. Maxilla 1 palp apical margin with robust setae; inner plate with five slender setae. Maxilla 2 outer lobe broader than inner lobe. Maxilliped strongly setose.

Pereon. Gnathopod 1 smaller than gnathopod 2; with long plumose setae on margins; coxa produced forward, anterior margin convex, ventral margin with long, plumose setal fringe; basis shorter than the coxa, with a long plumose setal fringe, distal lobe absent; merus produced to form a small, rounded anteroventral lobe; carpus shorter than merus, longer than propodus, lateral margins divergent at distal end; carpal lobe truncated; propodus ovoid; palm entire, straight, with posterodistal tooth absent, and mid-palmar tooth absent; dactylus subequal to palm. Gnathopod 2 margins with long, plumose setae; coxa with long, plumose setal fringe on ventral margin only; basis longer than coxa, and with long plumose setae in a fringe, distal lobe absent; merus produced to form a small, rounded, anteroventral lobe; carpus longer than merus, shorter than propodus; propodus subquadrate; palm entire, straight, with small, subacute posterodistal tooth, subquadrate mid-palmar tooth present; dactylus shorter than palm, tapering evenly.

Pereopods 3 and 4 similar in shape; coxae with a simple setal fringe. Pereopod 5 coxae with setal fringe on two-thirds of the ventral margin and with setae on the medial surface. Pereopod 6 basis with sparse medial setae. Pereopod 7 basis subrectangular. Pereopods 6 and 7 much longer than pereopods 3–5; distal articles with dense setae.

Pleon. Epimeron 3 with a small subacute tooth. Uropod 1 peduncle with 10 marginal robust setae; outer ramus shorter than inner ramus. Uropod 2 outer ramus subequal to inner ramus. Uropod 3 with seven distal peduncular robust setae; outer ramus subequal to inner ramus, hooks both strongly recurved, setal fringe present on lateral margin; inner ramus with both robust and slender setae. Telson rounded, with both lateral and apical slender setae (not in oblique rows); apical cusps present.

Female. Based on paratype 18 mm in length. Sexually dimorphic characters.

Pereon. Gnathopod 1 subequal to gnathopod 2, poorly setose; coxa produced forward, anterior margin straight, posterior two-thirds of ventral margin with long, plumose setal fringe; basis shorter than the coxa, with a long plumose setal fringe; merus produced to form a small, subacute anteroventral lobe; carpus longer than merus, subequal to propodus, lateral margins divergent at the distal end; carpal lobe truncated with rounded corners; propodus ovoid; palm entire, straight, with defining posterodistal tooth absent, and mid-palmar tooth absent; dactylus subequal to palm. Gnathopod 2 weakly setose; coxa with long plumose setal fringe on posterior twothirds of ventral margin; basis shorter than coxa, and weakly setose; merus produced to form a small, rounded, anteroventral lobe; carpus subequal to merus, shorter than propodus; propodus ovoid; palm entire, sinuous, with small, subacute posterodistal tooth, mid-palmar tooth absent; dactylus longer than palm and tapered evenly.

Remarks

Tattersall (1922) in his description says that even though Haswell’s description was really short and was not illustrated, his specimens actually fit the description and therefore named his specimens Cymadusa setosa . However, after looking at the specimens from the east coast of Australia, there are a number of differences between Haswell’s and Tattersall’s species. Cymadusa tattersalli n. sp. differs by maxilla 1 inner plate which has five slender setae (whereas C. setosa has 11 slender setae); gnathopod 1 basis is shorter than the coxa ( C. setosa basis is much longer than coxa), and has a long, dense, plumose setal fringe ( C. setosa has a short stubby fringe on the margin), the merus is produced to form a small subrounded anteroventral lobe ( C. setosa merus is produced to form a long, subacute lobe), carpus is short and broad ( C. setosa carpus is elongated and narrow), the propodal palm is entire and convex ( C. setosa propodal palm is entire and straight); uropod 3 has fewer robust setae on the peduncle and rami than on C. setosa .

Etymology. Named for W. Tattersall who documented this animal for the first time from the Western Australian coast.

Habitat. Cymadusa tattersalli occurs on brown algae.

Distribution. Cockburn Sound, Western Australia, Australia; Abrohlos Islands, Western Australia, Australia; Madagascar, Indian Ocean ( Map 1 ).

Figures

MAP 1. Global distribution of Cymadusa filosa Savigny, 1816 (*), Cymadusa ledoyeri n. sp. (•), Cymadusa tattersalli n. sp. (*), Cymadusa imbroglio Rabindranath, 1972 (Δ), Cymadusa setosa (Haswell, 1879) (v), Cymadusa vadosa Imbach, 1967 (&).