Mallacoota worimi, Hughes, 2011

HUGHES, L. E., 2011, New species of Hoho, Mallacoota and Parelasmopus (Maeridae: Amphipoda) from Australian waters, Zootaxa 2955 (1), pp. 1-79 : 65-68

publication ID

https://doi.org/ 10.11646/zootaxa.2955.1.1

DOI

https://doi.org/10.5281/zenodo.5460454

persistent identifier

https://treatment.plazi.org/id/7D26A779-EB19-400F-FF64-D22BFBDD6988

treatment provided by

Felipe

scientific name

Mallacoota worimi
status

sp. nov.

Mallacoota worimi View in CoL sp. nov

(Figs 42, 43)

Type material. Holotype, male, 9.2 mm, dissected,4 slides, AM P.85245 . Paratypes: female, 9.0 mm, dissected, 1 slide, AM P.85246; 1 male, 2 female, 1 immature, AM P.85247, south-west side of Boondelbah Island , east of Port Stephens (32°42”29’S 152°13”32’E), 10 m, corallimorphs and red algae on barnacles scraped off large boulder, sloping boulder reef meeting flat sand bottom, 10 March 2006, coll. A. Murray, RV Baragula ( NSW 2917 ) .

Type locality. South-west side of Boondelbah Island, east of Port Stephens , New South Wales (32°42”29’S 152°13”32’E).

Etymology. Named from the indigenous tribe of the Port Stephens region.

Description. Based on holotype, male, 9.2 mm, AM P.85245.

Head. Eyes ovate; lateral cephalic lobe broad, truncated, anteroventral margin with notch/slit. Antenna 1 longer than antenna 2; peduncular article 1 shorter than article 2, without robust setae along posterior margin; article 2 longer than article 3; flagellum articles broader than long, with 30 articles; accessory flagellum minute, with 3 articles. Antenna 2 peduncular article 2 cone gland not reaching to end of peduncular article 3; article 4 subequal in length to article 5; flagellum with 11 articles. Maxilla 1 inner plate subtriangular, with 2 apical plumose setae. Lower lip outer lobes with two pair of ducts, mandibular lobes apically subacute. Mandible accessory setal row well developed with 4 setae; molar well developed, triturative; mandibular palp well developed, 3-articulate; article 1 three times as long as broad, shorter than article 2; article 2 subequal to article 3, without setae; article 3 rectolinear, short (3 times as long as broad), subequal to article 1, with 2 apical setae.

Pereon. Gnathopod 1 coxa anterior margin concave, anteroventral corner produced, rounded; carpus about twice as long as broad, subequal in length to propodus; propodus medial surface with comb, palm acute, convex, entire, defined by posterodistal corner with 2 robust setae. Gnathopod 2 subchelate; basis slender, anterodistal corner subquadrate; merus with subquadrate distoventral corner; carpus compressed, lobate, projecting between merus teeth, palm defined by posteroventral tooth, without posterodistal robust setae, subpalmar surface smooth; dactylus without posteroproximal shelf, apically truncated, hammer-like, closing along palm. Pereopod 4 coxa posteroventral lobe well developed, with subrectangular posteromedial corner. Pereopods 5–7 basis slightly expanded, posterior margin convex, minutely castelloserrate, without long slender setae, posteroventral corner broadly rounded; merus and carpus weakly broadened; carpus and propodus with long, slender setae along posterior margin; propodus not expanded posterodistally; dactylar ungues simple. Pereonite 7 without carina.

Pleon. Pleonites 1–3 without carina. Epimera 1–2 posteroventral corner with small acute tooth. Epimeron 3 ventral margin smooth, posteroventral margin smooth, posteroventral corner subquadrate. Urosomite 1 bicarinate, subtriangular. Urosomites 2–3 without carina. Uropod 1 peduncle with 1 basofacial seta; outer ramus slightly shorter than inner ramus. Uropod 2 outer ramus slightly shorter than inner ramus. Uropod 3 rami distally truncated, apical robust setae long; inner ramus short (length 1.8 times breadth), slightly shorter than outer ramus; outer ramus longer than peduncle. Telson deeply cleft, as long as broad, tapering distally, apical margins concave, each lobe with 3 long and 1 short apical robust setae.

Female (sexually dimorphic characters), based on AM P.85246. Gnathopod 2 propodus without sparse setal bunches along posterior margin, palm without proximal shelf, defined by corner, with 2 robust setae; dactylus closing along palm.

Remarks. Mallacoota worimi sp. nov. is most similar to M. malua with the male gnathopod 2 propodus having a dense medial setal bunch, midmedial tooth and palm defining tooth. Mallacoota worimi sp. nov. can be separated by the presence of a small third tooth at the end of the palm and the large apically blunt dactylus. The blunt hammer-like dactylus is also known from M. nananui and M. latidactylus however the palmar tooth formula of gnathopod 2 differs between these species.

Distribution. Australia. New South Wales: Port Stephens (current study).

AM

Australian Museum

RV

Collection of Leptospira Strains

Kingdom

Animalia

Phylum

Arthropoda

Class

Malacostraca

Order

Amphipoda

Family

Maeridae

Genus

Mallacoota

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