Paradexamine quadratus Myers, 2009, sp. nov.
Creators: name: Myers, Alan A.
Publisher: name: Zenodo
Year: 2009
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Malacostraca
Amphipoda
Dexaminidae
Paradexamine
Paradexamine quadratus

description: <i>Paradexamine quadratus</i> sp. nov. (Figs 17, 18) <b>Type Material.</b> Holotype, female, 2.4 mm, AM P77999, Picnic Beach, Palfrey Island, Lizard Island (14°41.70' S, 145°26.92'E), subtidal, patch reef, rubble patch with sand bottom, 2 m, S.E. LeCroy, 3 July 2001 (SEL /LZI-2-1). Paratype, 1 female, AM P78000, same data as holotype. <b>Type Locality.</b> Palfrey Island, Lizard Island, Queensland, Australia (14°41.70'S 145°26.92'E). <b>Etymology.</b> From the Latin 'quadratus' = square, referring to the almost square basis of pereopod 7. <b>Description.</b> Based on holotype, female, 2.4 mm, AM P77999. <b>Head.</b> <i>Head</i> lateral lobes rounded. <i>Eye</i> large, about half or less length of head, composed of clear ommatidia (in alcohol). <i>Antenna 1</i> peduncle article 1 without process on posterior margin. <i>Antenna 2</i> very short, one third or less length of body; peduncle article 4 slender, parallel sided, weakly setulose; flagellum with 5 articles. <i>Maxilliped</i> palp 4-articulate. <b>Pereon.</b> <i>Gnathopod 1</i> carpus shorter than propodus; propodus not greatly expanded distally. <i>Gnathopod 2</i> carpus subtriangular, shorter than propodus. <i>Pereopods 3–7</i> simple or scarcely prehensile. <i>Pereopod 3</i> coxa, posterodistal corner rounded; dactylus more than half length of propodus. <i>Pereopods 5–7</i> of uniform morphology. <i>Pereopod 5</i> basis subrectangular, with posterodistal lobe, anterior margin with long robust setae. <i>Pereopod 6</i> basis very broad, subovate, posterior margin strongly convex, strongly serrated. <i>Pereopod 7</i> coxal gill present, basis strongly expanded, almost as broad as long, posterodistal margin strongly serrated. <b>Pleon.</b> <i>Segments</i> with the following dorsal spine arrangement (from urosomite 1 forwards): 3.3.3.3.1. <i>Epimeron 2</i> posterior margin minutely serrate, posteroventral corner subquadrate. <i>Epimeron 3</i> posterior margin minutely serrate, with strong posteroventral spine and accessory spines. <i>Urosomite 1</i> with dorsal spine and two dorsolateral spines. <i>Uropod 3</i> rami lacking long fine setae. <i>Telson</i> lobes distally serrated, each lobe with only 2–3 serrations of uneven size and shape, with distal spine, without subdistal robust seta, with subdistal slender seta. <b>Male</b> (sexually dimorphic characters). Unknown. <b>Habitat.</b> Rubble patch with sand bottom. <b>Remarks.</b> This species is close to <i>P. mozambica</i> Ledoyer, 1979, but that species has a very elongate pereopod 3 coxa that is drawn out at the posterodistal corner into a long, slender triangular process. In addition, epimeron 3 is 'denticule' on its ventral margin in <i>P. mozambicus</i> whereas in <i>P. quadratus</i> the ventral margin has strong spines. Also, the basis of pereopod 6 is less broad and 'finemente dentele' in <i>P. mozambicus</i>, but broad and strongly serrated in <i>P. quadratus</i>. <b>Distribution.</b> <i>Australia</i>. Queensland: Palfrey Island, Lizard Island (current study).
description: Published as part of <i>Myers, Alan A., 2009, Dexaminidae *, pp. 393-424 in Zootaxa 2260 (1)</i> on pages 415-417, DOI: 10.11646/zootaxa.2260.1.20, http://zenodo.org/record/5319784
description: {"references": ["Ledoyer, M. (1979) Les gammariens de la pente externe du grand recife de Tulear (Madagascar) (Crustacea, Amphipoda). Memorie del Museo Civico di Storia Naturale, Verona, 2, 1 - 150."]}