Monoculodes tropicalis Hughes &amp; Lowry 2009, sp. nov.
Creators: name: Hughes, L. E.
name: Lowry, J. K.
Publisher: name: Zenodo
Year: 2009
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Malacostraca
Amphipoda
Oedicerotidae
Monoculodes
Monoculodes tropicalis

description: <i>Monoculodes tropicalis</i> sp. nov. (Figs 3, 4) <b>Type material.</b> Holotype, female (dissected), 4 slides, 6.0 mm, AM P78134, Blue Lagoon, Lizard Island, Queensland, Australia (~ 14°40’S 145°28’E), plankton tow, night, no moon, 6 m, J.M. Leis, 20 October 1979 (JML 20-10 - 1). Paratypes: 3 unsexed, AM P78135 (JML 20-10 - 1). <b>Additional material examined</b>. 1 unsexed, AM P28309 (HI-3); 16 unsexed, AM P28310 (HI-3); 1 unsexed, AM P78136 (78 LIZ PBW-2); 1 unsexed, AM P78137 (78 LIZ PBW-6); 8 unsexed, AM P78138 (JDT / OPH 6c); 1 unsexed, AM P78139 (JML 7-10-1); 1 unsexed, AM P78140 (JML 7-10-2); 1 unsexed, AM P78141 (JML 16-10-7); 1 unsexed, AM P78142 (JML 16-10-8); 1 unsexed, AM P78143 (JML 16-10-9); 2 unsexed, AM P78144 (JML 20-10-2); 2 unsexed, AM P78145 (QLD 33); 3 unsexed, AM P78147 (QLD 63); 1 unsexed, AM P70873 (QLD 1654); 1 unsexed, AM P78148 (QLD 1900); 2 unsexed, AM P78149 (QLD 1922); 3 unsexed, AM P78150. <b>Type locality.</b> Blue Lagoon, Lizard Island, Great Barrier Reef, Queensland, Australia (~ 14°40’S 145°28’E). <b>Etymology.</b> The name signals the first record of <i>Monoculodes</i> from the tropical Indo-West Pacific. <b>Description.</b> Based on holotype, female (dissected), 6.0 mm, AM P78134. <b>Head</b>. <i>Head</i> rostrum well developed, broad, strongly deflexed, apically acute; eyes ovate, coalesced at top of head, situated fully within head; lateral cephalic lobe truncate. <i>Antenna 1</i> peduncle sparsely setose; peduncular article 1 without tooth, longer than article 2, longer than article 3; peduncular article 3 elongate, subequal to article 2; flagellum without callynophore, without calceoli. <i>Antenna 2</i> peduncle sparsely setose; calceoli with separated proximal and distal elements, proximal element convex, turret-shaped, broad lamellar receptacle with two apical cusps. <i>Mandible</i> molar well developed, triturative; left incisor a straight weakly serrate blade; palp elongate, article 2 straight, article 3 slightly shorter than article 2, with many marginal setae. <i>Lower lip</i> inner lobes separated. <i>Maxilla 1</i> outer plate with 9 setal-teeth. <i>Maxilla 2</i> inner plate without oblique setal row. <i>Maxilliped</i> inner plate present; palp article 2 expanded along midmedial margin. <b>Pereon</b>. <i>Gnathopods 1–2</i> well developed; propodi similar in shape, subchelate. <i>Gnathopod 1</i> subequal to gnathopod 2; carpal lobe short (extending less than half the length of the propodus), broad (as broad as long), divergent from propodus margin; propodus ovate, posterodistal margin smooth, palm acute, margin smooth. <i>Gnathopod 2</i> carpus elongate, longer than broad, carpal lobe short (extending less than half the length of propodus), broad (as broad as long), divergent from propodus margin; propodus ovate (about 2 x as long as broad), posterodistal margin smooth, palm acute margin smooth, setose. <i>Pereopods 3–4</i> carpi shorter than propodi; propodi posterior margins without setae, dactyli well developed, shorter than propodi, without apical setae. <i>Pereopod 3</i> coxa anterior margin rounded, anteroventral corner not produced, ventral margin convex. <i>Pereopod 4</i> coxa posterior margin excavate, with posteroventral lobe. <i>Pereopods 5–6</i> similar in form; propodi posterior margins sparsely setose; dactyli slender, tapering, each with circular unguis. <i>Pereopod 5</i> coxa small, depth distinctly less than coxa 4; dactylus longer than propodus. <i>Pereopod 6</i> dactylus longer than propodus. <i>Pereopod 7</i> basis with posteroproximal lobe, posterior margin straight, posterodistal lobe absent. <b>Pleon</b>. <i>Epimeron 3</i> posterodistal corner narrowly rounded to subquadrate. <i>Uropod 1</i> subequal in length to uropod 2; peduncle, lateral margin with 19 robust setae; rami subequal in length, with small robust setae; inner ramus margins smooth. <i>Uropod 2</i> shorter than uropod 3; rami subequal in length, with small robust setae. <i>Uropod 3</i> greatly enlarged; rami subequal in length, with small robust setae. <i>Telson</i> entire, apically truncate, with apical setae. <b>Habitat.</b> <i>Monoculodes tropicalis</i> <b>sp. nov.</b> has been found swimming in the water column at night and on shallow coarse to fine sand bottoms (1 to 17 m) during the day. <b>Remarks.</b> According to Bousfield &amp; Chevrier (1996) the genus <i>Monoculodes</i> is still poorly defined because of the limited description of the type species, <i>M. demissus</i> Stimpson, 1853. <i>Monoculodes tropicalis</i> <b>sp. nov.</b> is placed in <i>Monoculodes</i> (<i>sensu stricto</i>) based on the subsimilar gnathopods with short carpal lobes (Bousfield &amp; Chevrier 1996). <i>Monoculodes tropicalis</i> differs significantly from the other Indo-West Pacific species of <i>Monoculodes</i> (<i>M. abacus</i> J.L. Barnard, 1961, <i>M. dentimanus</i> Jo, 1990, <i>M. koreanus</i> Jo, 1990, <i>M. muwoni</i> Jo, 1990) as follows: gnathopods 1–2 propodi more broadly subovoid in shape, and pereopod 7 basis with posterior proximal lobe and without posterodistal lobe. The presence of calceoli on the flagellum of antenna 2 (Fig. 3 A, B) is apparently the first record of calceoli for the genus <i>Monoculodes</i>. The structure of the calceolus conforms to the oedicerotid type seven as described by Lincoln &amp; Hurley (1981) with separated proximal and distal elements. The broad lamellar receptacle around the proximal element has two apical cusps like those noted on <i>Oediceropsis bicornuta</i> Bellan-Santini, 2007. This appears to be the first type seven calceolus reported with a convex, turret-shaped proximal element. Previously documented oedicerotid calceoli have a concave cupshaped proximal element. <i>Monoculodes tropicalis</i> can be separated from other oedicerotids on the GBR by the short, subchelate gnathopods with subovoid propodi and short-lobed carpi. <i>Monoculodes tropicalis</i> is the first tropical species described in the genus. Ledoyer (1984) reported a single specimen of <i>Monoculodes</i> sp. from New Caledonia, but did not illustrate or describe the material. <b>Distribution.</b> <i>Australia.</i> Queensland: Goodes and Hawkesbury Islands, Torres Strait (current study); Eagle and Lizard Islands (current study); Fantome Island (current study); Heron Island (current study).
description: Published as part of <i>Hughes, L. E. &amp; Lowry, J. K., 2009, Oedicerotidae *, pp. 746-758 in Zootaxa 2260 (1)</i> on pages 750-751, DOI: 10.11646/zootaxa.2260.1.40, http://zenodo.org/record/5307044
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