Maeraceterus bramblensis
Creators: name: Hughes, Lauren E.
Publisher: name: Zenodo
Year: 2016
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Malacostraca
Amphipoda
Maeridae
Maeraceterus
Maeraceterus bramblensis

description: Maeraceterus bramblensis gen. et sp. nov.
(Figs 60–62)
Type material. Holotype male, 5.1 mm, dissected, 4 slides, AM P.79457, Princess Royal Harbour, Bramble Point, Western Australia (35°2'S 117°55' E), 1–1.5 m, on seagrass Poisidonia australis, diver held corer, January 1988, coll. P. Hutchings and party.
Additional material examined. Tasmania: 1 male, dissected, 4 slides, AM P. 97857, North East River (39°46′S 147°58′E), depth unknown, 8 May 1997, coll. A. Davey (CAM 78); 1 b female, dissected, 1 slide, AM P.88467, North East River (39°46′S 147°58′E), depth unknown, 8 May 1997, coll. A. Davey (CAM 78).
Type locality. Princess Royal Harbour, Bramble Point, Western Australia (35°2′S 117°55′ E).
Etymology. Named from the type locality.
Description. Based on holotype male, 5.1 mm, AM P.79457.
Head. Eyes ommatidea scattered; lateral cephalic lobe broad, apically rounded, anteroventral margin with notch/slit, anteroventral corner truncate. Antenna 1 longer than antenna 2; peduncular article 1 shorter than article 2, with 1 robust seta posterodistally; peduncular article 2 longer than article 3; flagellum articles as long as broad, with 16 articles; accessory flagellum short, significantly less than half length of primary flagellum, with 3 articles. Antenna 2 peduncular article 4 longer in length than article 5; flagellum with 10 articles. Mandible accessory setal row, well developed with 5 setae; palp well developed, article 1 length 0.9 × width, shorter than article 2; article 2 longer than article 3, with a few slender setae; article 3 rectilinear, long, 3.5 × as long as broad, longer than article 1, with 3 apical slender setae. Lower lip lobes without apical ducts; mandibular lobes apically rounded. Maxilla 1 inner plate with 3 apical plumose setae; outer plate palp with apical slender setae.
Pereon. Gnathopod 1 coxa anterior margin concave, anteroventral corner produced, subacute, posteroventral corner without notch; merus with posteroventral corner subquadrate; carpus length twice width, 1.3 × propodus length, without rows of short medial setae; propodus rectilinear, medial surface setal comb absent, palm subacute, weakly convex, entire, with weakly defined posterodistal corner; dactylus closing along palm.
Gnathopod 2 symmetrical, subchelate; coxa posteroventral corner without notch; basis broad, anterodistal corner with pair of well-developed rounded lobes; ischium anterior margin with pair of well-developed lobes; merus with subacute posteroventral corner; carpus compressed, length 0.9 × width, posterior margin with long slender setae; propodus subovate, length 1.8 × width, posterior margin with clusters of long slender setae, palm angle subacute, posterodistal shelf subrectangular, margin sculpted, with 4 rounded teeth, palm weakly defined with small rounded tooth, without robust setae; dactylus closing along and reaching end of palm.
Pereopod 4 coxa without posterodistal lobe. Pereopods 5–7 slender distally; basis posteriorly expanded, margin weakly convex, without long slender setae; merus and carpus slightly broadened; dactylus unguis simple. Pereopod 6 basis larger than pereopod 7.
Pleon. Pleonites 1–3 dorsally smooth. Epimera 1–3 posterior margin smooth, corner with small tooth. Urosomites 1–3 without carina. Uropod 1 peduncle with 1 basofacial seta; rami subequal, 0.9 × peduncle length. Uropod 2 peduncle length 0.8 × outer ramus; inner ramus longer than outer ramus. Uropod 3 unknown. Telson deeply cleft, length subequal to width, lobes weakly divergent, tapering distally, lobes apical margins concave, each lobe with 3 apical and 1 lateral pair of robust setae.
Remarks. Maeraceterus bramblensis gen. et sp. nov. differs from M. taaroa gen. et sp. nov. in the number of teeth on the male gnathopod 2 palm and the absence of a palm defining robust setae which is present in the latter species. In M. bramblensis the ischium is without robust setae while M. taaroa has a well-developed row of long robust setae on the posterior margin.
Maeraceterus bramblensis has the unusual state of pereopod 6 basis being larger than that of the pereopod 7 basis (observed on both left and right sides of the holotype). This character is not observed in M. taaroa and therefore is considered a species rather than generic level character.
Distribution. Australia. Western Australia: Bramble Point (current study). Tasmania: North East River (current study).
description: Published as part of 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), pp. 1-81 in Zootaxa 4115 (1) on pages 72-75, DOI: 10.11646/zootaxa.4115.1.1, http://zenodo.org/record/255539