Elasmopus pectenicrus ( Bate, 1862 )

Lowry, J. K. & Hughes, L. E., 2009, Maeridae, the Elasmopus group *, Zootaxa 2260 (1), pp. 643-702 : 656-659

Elasmopus pectenicrus ( Bate, 1862)

( Figs 7 , 8 )

Moera pectenicrus Bate, 1862: 192 , pl. 34, fig. 8.

Elasmopus pectenicrus . —K.H. Barnard, 1916: 197, pl. 28, fig. 33. — Schellenberg, 1928: 647. —? Shoemaker, 1935: 238. — Pirlot, 1936: 312. — Schellenberg, 1936: 13. —K.H. Barnard, 1937: 161. — Schellenberg, 1938: 55. — Ruffo, 1938: 162. —K.H. Barnard, 1940: 461. — Rudwick, 1951: 149, 152. — Reid, 1951: 236, fig. 32. —J.L. Barnard, 1955: 8, fig. 4. — Ruffo, 1959: 21. — Nayar, 1959: 27, pl. 9, figs 20–35. — Sivaprakasam, 1968: 103. — Sivaprakasam, 1969: 45, fig. 6b–c. — Ruffo, 1969: 28. —J.L. Barnard, 1970: 125: figs 73–74. — Griffiths, 1974a: 235. — Griffiths, 1974b: 289. — Griffiths, 1975: 121. —G. Karaman, 1982: 286, fig. 192. — Ledoyer, 1983: 475, figs 179, 180. — Soares et al., 1987 /89: 241, pl. 2, figs 1–12. — Wakabara et al., 1991: 73. — Wakabara & Serejo, 1998: 575. — Appadoo & Steele, 1998: 639. — LeCroy, 2000: 88, fig. 129. — Appadoo & Myers, 2003: 65 , fig. 4.

Elasmopus serrula . — Walker, 1904: 277, pl. 8, fig. 37. — Walker, 1909: 336.

Elasmopus pectinicrus . — Gravely, 1927: 123.

? Elasmopus brasiliensis . — Oliveira, 1951: 4, pls 1–4.

Material examined. Male, 7.0 mm (4 slides), AM P78549 ( JML 84/4/11/4/N); 10+ unsexed, NTM Cr015421 ( MAGNT 26); 8 unsexed, NTM Cr015429 ( MAGNT 27); 13 unsexed, NTM Cr015447 ( MAGNT 28); 10+ unsexed, NTM Cr015463 ( MAGNT 30); 1 unsexed, NTM Cr015784.

Type locality. New Guinea .

Description. Based on a male, 7.0 mm, AM P78549.

Head. Head eyes subovate; lateral cephalic lobe broad, apically truncate, anteroventral margin with notch/slit, anteroventral corner rounded. Antenna 1 longer than antenna 2; peduncular article 1 subequal in length to article 2, with 1 robust seta on posterodistal margin; article 2 longer than article 3; accessory flagellum short, with 3 articles; flagellum with 14 articles. Antenna 2 peduncular article 4 subequal to article 5; flagellum with 9 articles. Mandible incisor a smooth cutting edge with 2 apicomedial cusps; accessory setal row with 3 setae; palp well developed, 3-articulate; article 1 about twice as long as broad, shorter than article 2, inner margin article 1 not produced distally; article 2 slightly shorter than article 3; article 3 short (2.7 x as long as broad), strongly falcate, longer than article 1.

Pereon. Gnathopod 1 coxa anteroventral corner produced, rounded, anterior margin slightly concave; carpus about 2 x as long as broad, subequal in length to propodus, (length 1 x propodus); propodus palm acute, straight, entire, defined by posterodistal corner, with posterodistal robust seta. Gnathopod 2 coxa posteroventral corner notch absent; basis slender; merus with rounded distoventral corner; carpus compressed, projecting between merus and propodus; propodus expanded, with slender setae along posterior margin, palm acute, straight, smooth, palm about half length of propodus, with subtriangular distomedial shelf, with group of 7 robust setae on shelf, palmar margin without robust setae, without teeth, subpalmar surface with long seam, without posteroventral corner, without posterodistal robust setae; dactylus reaching end of palm, closing along margin of palm, without setae on anterior margin, without posteroproximal shelf, apically subacute. Pereopod 4 coxa posteroventral lobe slightly developed, with rounded posteromedial corner.

Pereopod 5 basis expanded; posterior margin slightly convex, without long slender setae, posteroventral corner subquadrate; carpus and propodus without long, slender setae along anterior margin. Pereopod 6 basis posterior margin convex proximally, castelloserrate, excavate distally, without long slender setae, posteroventral corner produced distally, lobate; merus and carpus broadened; carpus and propodus without long, slender setae along margins; propodus slightly expanded posterodistally to from a hood-like projection. Pereopod 7 basis posterior margin convex, castelloserrate, without long slender setae, produced posterodistally, posteroventral corner subquadrate; merus and carpus not broadened; propodus slightly expanded posterodistally to from a hood-like projection.

Pleon. Pleonites 1–3 dorsally smooth, without setae, spines or carinae. Epimeron 1 posteroventral corner subquadrate. Epimeron 2 posteroventral corner acute. Epimeron 3 ventral margin smooth, posteroventral margin smooth, posteroventral corner with small acute spine. Urosomites 1–3 dorsally smooth, without setae, spines or carinae. Uropod 1 with basofacial robust seta. Uropod 3 rami distally truncated, apical robust setae long and short; inner ramus short, about 0.5 x outer ramus; inner ramus short (length 1 to 1.9 x breadth); outer ramus short (length 1.8 x breadth), subequal in length to peduncle, 1-articulate. Telson moderately cleft (30 to 65%), broader than long, short, truncated distally, apical margins concave, without dorsal robust setae, each lobe with 3 apical/subapical robust setae, without robust setae on inner and outer margins.

Habitat. Marine, epibenthic hard substrates, occasionally found on the carapace of the loggerhead sea turtle, Caretta caretta ( LeCroy 2000) .

Remarks. Although the original description of E. pectenicrus ( Bate, 1862: 192, pl. 34, fig. 8) is poor and the type locality, New Guinea, is vague, the illustration of the distinctive basis of pereopod 6 has been widely used to identify the species across the Indo-West Pacific, the Red Sea and even the eastern Atlantic and Caribbean, often with few (K.H. Barnard 1916; Reid 1951) or no illustrations ( Schellenberg 1928, 1936, 1938; Pirlot 1936; K.H. Barnard 1937; Ruffo 1938, 1959, 1969; Sivaprakasam 1968; Griffiths 1974a, b, 1975). Comparing recent redescriptions of the species ( Ledoyer 1983 from Madagascar and Appadoo & Myers 2003 from Mauritius) with the current redescription from the GBR indicates significant morphological differences between populations (table 1). It is possible that rather than being a widespread ‘superspecies’, E. pectenicrus is actually a group of cryptic species ranging throughout the tropics. Because the type locality is vague and the type material is lost, pinning down the actual morpho-type is impossible, but the material described in this paper from the GBR is geographically the closest. A neotype needs to be established based on material from New Guinea.

Elasmopus pectenicrus is distinguished from other species on the GBR by the distinctive shape of the pereopod 6 basis.

Distribution. Australia. Queensland: Thursday Island, Torres Strait (current study); Lizard Island (current study). Northern territory: Groote Eylandt; Raffles Bay, Cobourg Peninsula (current study). Brazil. Rio de Janeiro ( Oliveira, 1951). Egypt. Suez ( Walker 1909); Port Said ( Schellenberg 1928). India. Madras ( Nayar 1959; Sivaprakasam 1968); Cape Comorin, Tuticorin, Kilakkarai, Ramswaram, Pamban, Calimere, Kovelong, Madras Harbour, Visakhapatnam Harbour ( Sivaprakasam 1968); Gulf of Manaar ( Sivaprakasam 1969). Indonesia. Sangeang Island, Flores Sea ( Pirlot 1936). Israel. ( Ruffo 1959).? Madagascar. ( Ledoyer 1983). Mauritius. ( Appadoo & Myers 2003). Papua New Guinea. ( Bate 1862); Ralum, Bismarck Archipelago ( Schellenberg 1938). South Africa. Buffels Bay (False Bay) and Durban (K.H. Barnard 1916); Still Bay and East London (K.H. Barnard 1940). Sri Lanka. Galle ( Walker 1904). Tanzania. Zanzibar ( Walker 1909). USA. Puerto Rico ( Shoemaker, 1935); Pearl Harbor, Hawaii (J.L. Barnard, 1955, 1970); South Florida, Florida Keys and the Dry Tortugas ( LeCroy 2000).

Figures

FIGURE 7. Elasmopus pectenicrus (Bate, 1852), male, 7.0 mm, AM P78549, Lizard Island, Great Barrier Reef.

FIGURE 8. Elasmopus pectenicrus (Bate, 1852), male, 7.0 mm, AM P78549, Lizard Island, Great Barrier Reef.