Pereionotus yongensis, Coleman, Oliver & Lowry, James K., 2012

Coleman, Oliver & Lowry, James K., 2012, The genus Pereionotus (Crustacea, Amphipoda, Phliantidae) from Australia, Zootaxa 3486, pp. 63-88 : 83-86

Pereionotus yongensis sp. nov.

( Figs 14–15 )

Pereionotus thomsoni .— Coleman, 2009b: 766 , figs 1–2, pl.5C.

Material examined. Holotype, male, 2.6 mm, AM P.71365, Half Mile Opening, Yonge Reef, Queensland, Australia (14°34.556’S 145°36.726’E), sponges, channel between outer barrier reefs, 10 m depth, C. Serejo, 4 March 2005, QLD 1820.

Paratype, female, AM P.78903, Picnic Beach, Palfrey Island, Lizard Island, Queensland, Australia (14°41'42"S 145°26'55"E), protected beach, coral rubble, sand, algae, intertidal, Sara LeCroy, 3 July 2001, SEL/LZI-2-3.

Type locality. Half Mile Opening, Yonge Reef, Queensland, Australia (14°34.556’S 145°36.726’E) 10 m depth.

Etymology. This species is named after the type locality Yonge Reef.

Diagnosis. Dorsal keel consisting of slightly rising dorsal humps on pereonites 2–7. Antenna 1 peduncular article 1 slender with subterminal lateral lobe; peduncular article 2 longer than wide. Coxae 1–4 with dense fringe of long slender setae on the distal margins of. Pereopods 1–7 propodi without additional robust setae half-way on posterior and anterior margins.

Description (modified after Coleman 2009b). Based on male holotype, 2.6 mm. Head and body. Body depressed, with dorsal keel, coxal plates moderately splayed. Pereonite 1 with 2 dorsal shallow carinae, pereonites 2–6 and pleonites 1–2 with hump-like shallow carinae. Head with protruding eyes and short rostrum. Antenna 1 peduncular article 1 dorsolaterally expanded into subacute tooth; article 2 with a shorter pointed tooth; flagellum consisting of only one article with long aesthetascs apically. Antenna 2 with apical bundle of aesthetascs on second flagellar article; slender, reaching middle of article 2 of antenna 1 in lateral view. Mandible without palp, incisor multidentate, molar robust. Lower lip with wide lobes. Maxilla 1 inner plate simple; palp short, uni-articulate. Maxilla 2 inner and outer plates basally fused. Maxilliped inner plate subrectangular with 3 nodular setae apically; outer plate longer than palp; palp 3-articulate.

Pereon. Coxae 1–4 with distal row of long slender setae. Gnathopod 1 coxa anterior margin slightly excavate; basis shorter than coxa; ischium longer than merus; carpus slightly expanded distally; propodus medial face with transverse row of stout plumose setae and posterodistal robust setae; dactylus falcate, with simple seta on inner curvature. Gnathopod 2 similar to gnathopod 1, but coxa with anterior margin straight and row of medial propodus setae not developed. Pereopod 3 coxa wider than that of gnathopod 2; basis and ischium similar, but merus and to a lesser extent the carpus drawn out into an anteromarginal rounded lobe; propodus and dactylus as for gnathopod 2. Pereopod 4 coxa with posteromarginal subacute lobe; basis to dactylus as for pereopod 3. Pereopods 5 and 6 coxa bilobed, more than 2x as long as deep; basis expanded into rounded posterior lobe; ischium long; merus with posterodistal rounded lobe; carpus short, subrectangular; propodus and dactylus as in preceding appendages. Pereopod 7 basis posteroproximal margin rounded, constricted and quadrate distally; ischium to dactylus similar to preceding appendages, except for a more extended merus lobe.

Pleon. Urosomite 1 longest. Uropod 1 outer ramus slightly shorter than inner, both rami with one short rounded robust seta apically. Uropod 2 peduncle very short, inner ramus surpasses outer, both rami with one terminal rounded robust seta. Uropod 3 hidden below telson, rami lacking. Telson wider than long, subtriangular with rounded apex.

Sexual dimorphism. Female with wider body. Processes on peduncular articles 1–2 of antenna weakly developed.

Habitat. Found in between sponges.

Remarks. See general discussion.

Distribution. Australia: Queensland, Yonge Reef, close to Lizard Island.

Figures

FIGURE 14 a – i: Pereionotus yongensis sp. nov., holotype male, 2.6 mm, AM P 71365. a) lateral habitus; b) antenna 2; c) dorsal habitus; d) antenna 1; e) lower lip; f) maxilla 1; g) maxilla 2; h) maxilliped; i) mandible.

FIGURE 15 a – g: Pereionotus yongensis sp. nov., holotype male, 2.6 mm, AM P 71365. a) pereopod 1; b) pereopod 2; c) pereopod 3; d) pereopod 4; e) uropod 1; f) uropod 2; g) telson.