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

description: <i>Paradexamine massa</i> sp. nov. (Figs 13, 14) <b>Type Material.</b> Holotype, male, 2.5 mm, AM P78001, Picnic Beach, Palfrey Island (14 o 41.70'S 145 o 26.92'E), subtidal, protected beach, coral rock, rubble, sand patches, 0.3 m, S.E. LeCroy (SEL /LZI-2-6). Paratypes, 6 unsexed, AM P78002, same data as holotype. <b>Additional material examined.</b> 5 females, AM P71106 (QLD 1710); 1 male, AM P71047 (QLD 1718). <b>Type Locality.</b> Palfrey Island, Lizard Island, Queensland, Australia (14°41.70'S 145°26.92'E). <b>Etymology.</b> From the Latin 'massa' = lump, referring to the swelling on the posterior margin of peduncle article 1 of antenna 1. <b>Description.</b> Based on holotype, male, 2.5 mm, AM P78001. <b>Head.</b> <i>Head</i> lateral lobes acute. <i>Eye</i> huge, more than half length of head, with black central core. <i>Antenna 1</i> peduncle article 1 with medial rounded process on posterior margin. <i>Antenna 2</i> length unknown; peduncle article 4 broader proximally, finely setulose; flagellum unknown. <i>Mandible</i> palp absent; incisor process lacking robust setal row. <i>Maxilla 1</i> palp stout, about three times as long as broad. <i>Labium</i> mandibular lobes acute. <i>Maxilliped</i> palp 4-articulate. <b>Pereon.</b> <i>Gnathopod 1</i> carpus longer than propodus; propodus not greatly expanded distally. <i>Gnathopod 2</i> carpus elongate, slender, longer than propodus. <i>Pereopods 3–7</i> simple or scarcely prehensile. <i>Pereopod 3</i> coxa, posterodistal corner with single spine; dactylus much less 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 short robust setae. <i>Pereopod 6</i> basis pyriform, broadest proximally, posteroproximal margin convex, with robust setae, posterodistal margin substraight, smooth. <i>Pereopod 7</i> coxal gill present; basis moderately expanded, longer than broad, posterodistal margin serrated. <b>Pleon.</b> <i>Segments</i> with the following dorsal spine arrangement (from urosomite 1 forwards): 1.3.3.0.0. <i>Epimeron 2</i> posteroventral corner produced into a small spine. <i>Epimeron 3</i> posterior and ventral margins smooth, with a single strong posteroventral spine. <i>Urosome</i> with urosomites 2–3 fused. <i>Urosomite 1</i> with dorsal spine only. <i>Uropod 3</i> rami with many long fine setae. <i>Telson</i> lobes distally serrated, each lobe with multiple serrations of uneven size and shape, without distal spine, with subdistal robust seta, without subdistal slender seta. <b>Female</b> (sexually dimorphic characters). Based on female, 2.4 mm, AM P71106. <i>Eye</i> large, about half or less length of head. <i>Antenna 2</i> peduncle article 4 slender, parallel sided, weakly setulose. <i>Uropod 3</i> rami lacking long fine setae. <b>Habitat.</b> Soft bottom with sponges, corals, crinoids, hydroids, <i>Halimeda</i>. <b>Remarks.</b> This species is close to <i>P. pacifica</i> (Thomson, 1879), but differs in the shape of the basis of pereopods 6 and 7. The posterodistal margin of the basis of pereopod 6 is almost straight and asetiferous in <i>P. massa</i> (weakly convex and evenly setose in <i>P. pacifica</i>) and that of pereopod 7 is strongly serrate in <i>P. massa</i> (weakly serrate in <i>P. pacifica</i>). In addition, the inner plate of maxilla 1 is asetiferous in <i>P. massa</i> (with two distal setae in <i>P. pacifica</i>) and the mandibular processes of the labium are blunt in <i>P. massa</i> (finely pointed and recurved in <i>P. pacifica</i>). <b>Distribution.</b> <i>Australia</i>. Queensland: Palfrey Island and North Point, 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 411-413, DOI: 10.11646/zootaxa.2260.1.20, http://zenodo.org/record/5319784
description: {"references": ["Thomson, G. M. (1879) New Zealand crustacea, with descriptions of new species. Transactions and Proceedings of the New Zealand Institute, 11, 230 - 248."]}