Gabophlias kerstinae, Coleman, Oliver & Lowry, James K., 2012

Coleman, Oliver & Lowry, James K., 2012, Two new species of Gabophlias (Crustacea, Amphipoda, Phliantidae) from Australia, Zootaxa 3441, pp. 21-35 : 28-34

Gabophlias kerstinae sp. nov.

( Figs 6–10)

Material examined. Holotype, male?, 4 mm, MV J56512 , west end, Michaelmas Island, Western Australia, Australia, 35°02'48''S 118°01'24''E, 15 m depth, G.C. Poore & H.M. Lew Ton, 17 April 1986, SCUBA, SWA 65.

Type locality. West end, Michaelmas Island, Western Australia, Australia, 35°02'48''S 118°01'24''E, 15 m depth.

Additional material examined. 1 specimen, unknown sex, 2.8 mm, AM P.80324, rocks near Migo Island, Port Harding, Torbay, Western Australia, Australia (35°6'S 117°36'E), 7 m depth, brown & red algae, some sponge & ascidian, J.K. Lowry, 15 December 1983, WA-153; 1 female, 3 juveniles, MV J22576 , 11.7 km west of Point Ricardo, Victoria, eastern Bass Strait, Australia (37°49.89'S 118°30.13'E), coarse sand, 27 m depth, Smith- McIntyre grab, N. Coleman; 2 specimens, AM P. 80327, 500 m off Chinamans Rock, Kalbarri, Western Australia, Australia (2742'S 1146'E), rocky bottom, curly brown plus coralline algae, 6 m depth, J.K. Lowry 10 January 1984.

Etymology. This species is named for Kerstin Moos, the dear sister in law of the senior author.

Description. Based on male? holotype, 4 mm. Habitus. Body ( Fig. 6a) dorsoventrally flat, oval in shape, coxal plates and appendages splayed. Pereonites with dorsal carina ( Fig. 6d), lowest on pereonite 1, higher on pereonites 3–4 and pereonite 7 ( Fig. 6d). Pereonites relatively slender. Pleonites 1–3. Pleonite 1 pointed posteromarginally. Pleonite 3 longest, with shallow mid-dorsal elevation on pleonite 1.

Head wider than long, not much surpassed by coxa 1; with a short rounded rostrum; eyes small, rounded. Antenna 1 ( Fig. 6b) peduncle article 1 distally expanded, laterodistally roundly lobate, mediodistal region a rounded protrusion; article 2 as wide as article 1, with rounded medial lobe, bordered with short setae, drawn out distally, obliquely truncate, reaching distal margin of article 3; article 3 short, distally rounded; flagellum 3- articulate, with an apical tuft of long aesthetascs. Antenna 2 ( Fig. 6e) peduncle article 4 expanded distally, anterior and posterior margins straight, distolateral corner drawn out; article 5 shorter than article 4, margins convex; flagellum 3-articulate. Upper lip ( Fig. 6f) wider than long and rounded to truncate distally. Mandibles ( Fig. 6c) both with dentate incisor. Maxilla 1 ( Fig. 7a) with 5 distal robust setae on outer plate, inner plate missing (?), palp not developed. Maxilla 2 ( Fig. 6g) inner plate more than twice as wide as outer plate, both plates with few short stout setae apicomarginally. Maxilliped ( Fig. 7b) inner plate apically truncate, with nodular setae distally; outer plate wide and rounded with few setae mediomarginally; palp 4-articulate, article 3 longest, as wide as article 2; article 4 rather straight, pointed.

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e Pereon. Pereopod 1 ( Fig. 7c, d) coxa subtriangular; basis to dactylus short, not surpassing distal margin of coxa, basis expanded antero- and posterodistomarginally, twice as wide as ischium; ischium subequal in length to merus; carpus expanded distally, with a few stout setae anterodistally; propodus anteroproximally with a group of stout setae, posterior margin proximally roundly produced with 1 stout robust seta and additional robust seta distally (1+1 arrangement); dactylus stout. Pereopod 2 ( Figs 7e, 8a) coxa subrectangular; basis to dactylus short, not surpassing distal margin of coxa; basis to dactylus similar to that of pereopod 1, but only 2+1 robust setae on propodus posteromarginally. Pereopod 3 ( Fig. 8b, c) coxa subrectangular, but wider than that of pereopod 2; basis distally slightly expanded; ischium subequal in length to merus; merus expanded anterodistomarginally; carpus wider than long; propodus tapering distally, produced proximoposteromarginally, with 2+1 robust setae; dactylus falcate. Pereopod 4 coxa ( Fig. 8d) expanded distally with a proximoposteromarginal excavation; basis subrectangular; merus to dactylus similar as in pereopod 3. Pereopod 5 ( Fig. 9a) coxa wider than long, bilobed, anterior lobe wider and distinctly longer than posterior lobe; basis ovoid with long ventral lobe; merus very large, 2.7 × as wide as ischium, distally expanded, especially posterodistomarginally; carpus wider than long, distally expanded; propodus tapering distally, anteromarginally weakly concave, anteroproximally lobate and 2+1 robust setae; dactylus falcate. Pereopod 6 ( Fig. 9b) coxa similar in shape to that of pereopod 5 but smaller; basis as wide as long, posterior lobe as wide as that of pereopod 5; merus and propodus similar in shape as for pereopod 5.

Pereopod 7 ( Fig 9 c) similar to pereopod 6 but shorter and basis somewhat smaller.

Pleon. Pleopod 1 ( Fig. 9d, e) medially weakly expanded peduncle, 5 coupling hooks on inner margin; inner ramus slightly shorter than outer. Pleopod 2 ( Fig. 10a) peduncle subtriangular, medially expanded and tapering, with 5 coupling hooks distally, inner ramus distinctly shorter than outer. Pleopod 3 ( Fig. 10b) peduncle shorter than wide, medially narrowly extended with 5 coupling hooks; inner ramus reduced to a small scale, outer ramus about 4 × the length of inner ramus.

Uropod 1 ( Fig. 10f) peduncle slightly shorter than outer ramus; inner ramus 1/3 of outer ramus and half the width. Uropod 2 ( Fig. 10c, e) peduncle half the length of that of uropod 1; outer ramus 1.6 × as long as inner. Uropod 3 ( Fig. 10d) mostly covered by telson; peduncle about 2 × as long as wide; only one slender ramus present, 3 × as long as wide. Telson ( Fig. 10c) wider than long, convex lateromarginally, tapering distally.

Remarks. For differences to Gabophlias olono and Gabophlias gabiae sp. nov. see table 1. The specimen from Migo Island (AM P.80324) has a lower inconspicuous dorsal carina, only stronger on pereonites 3 and 4, with pointed protrusions and a clear hump on pereonite 7. The body is somewhat narrower, but otherwise the appendages are very similar to the holotype. Due to the sparse material it cannot be determined if this is a separate species or a variation from the holotype morphology. The two specimens from Kalbarri, Western Australia (AM P.80327) do not have a dorsal carina, they are perfectly smooth, which would key out to G. g a b i a e sp. nov., but these specimens have the typical antenna 1 and the bulky pereopods 5–7 of G. kerstinae sp. nov. We evaluate this as variation.

Distribution. Australia: Victoria and Western Australia.

ABLE 1. Comparison of the 3 Gabophlias species.