Parelasmopus setiger Chevreux, 1901

Myers, A. A., 2016, Amphipoda (Crustacea) from Palau, Micronesia: Families Maeridae and Melitidae, Zootaxa 4170 (3), pp. 451-474 : 461-465

? Parelasmopus setiger Chevreux, 1901

( Figs 12–14 )

? Megamoera suensis Haswell, 1879: 335 –336, pl. 21, fig. 5.

Megamoera suensis .— Miers 1884: 317 –318.

Megamoera haswelli Miers, 1884: 318 [name in text].

Not Megamoera suensis . — Haswell 1885: 103 –104, pl. 15, figs 1–4 [= Maera hamigera (Haswell) fide Stebbing 1906, but see Stebbing 1910: 600.]

Elasmopus suensis .— Stebbing, 1906: 442 –443.

Parelasmopus setiger Chevreux, 1901: 412 –418, figs 32–39.— Barnard, 1972: 254, fig.152.— Ledoyer, 1983: 586, figs 222, 223.— Azman & Ali, 2015: 60, figs 2–9.

Parelasmopus suluensis .— Chilton, 1922: 7, 8, fig. 3 [not Dana].

? Parelasmopus suluensis .— Walker, 1904: 278, pl. 6, fig. 3.

? Parelasmopus siamensis Wongkamhaeng, Coleman & Pholpunthin, 2013: 525 , figs 19–24.

Material. 1 male (OUMNH.ZC. 2002-24 -153), Lighthouse Reef, outer side, from rubble (mainly Acropora plates and bushy forms heavily encrusted), - 5 m depth; 07°16.615'N, 134°27.606'E; leg. S. De Grave & C. Burras, 21 May 2002; 1 female (OUMNH.ZC. 2002-24 -154), Beluu Lukes Reef, eastern side, from heavily encrusted loose rubble, - 5 m depth; 07°17.530'N, 134°30.870'E; leg. S. De Grave & C. Burras, 20 May 2002; 8 females (OUMNH.ZC. 2002-24 -155), Omodes intertidal seagrass bed (sparse Enhalus ) on rubble flat, hand netting; 07°19.439'N, 134°29.231'E; leg. S. De Grave & C. Burras, 23 May 2002; 2 females (OUMNH.ZC. 2002-24 -156), outside Risong, rubble tray left for 10 days, seagrass (nearly intertidal); 07°17.917'N, 134°28.560'E; leg. S. De Grave & C. Burras, 2 June 2002.

Remarks. There has been much confusion concerning the species of Parelasmopus (see Berents 1983, Lowry & Hughes 2009).

Present material is similar to that described by Azman & Ali, 2015 from Singapore as P. s e t i ge r Chevreux, 1901, but it differs in several important character states. The pereopod 7 basis in the Singapore material is irregularly lobed and bears very long setae. In present material the posterior margin bears a series of acute spines and lacks any long setae altogether. Something approaching this spine structure is seen in P. siamensis Wongkamhaeng, Coleman & Pholpunthin, 2013 from Thailand, but that species also has long setae on the basis of pereopod 7. The shape of the palm of the male gnathopod 2 in the two materials (present and Singapore) is also different. In Singapore material the palm is somewhat irregular, very transverse and ends at almost a right angle with the posterior margin, whereas in present material the palm is smooth, slightly sloping and evenly rounded with the posterior margin. Material from Madagascar ( Ledoyer 1983) has almost the same strong spines on the basis of P7 as present material, but also has long setae present. Figured type material by Chevreux (1901) is not very detailed but appears to have an irregularly lobed pereopod 7 basis lacking setae, though the setae may have been omitted in error. The male gnathopod 2 palm is poorly figured by Chevreux (1901), but appears to join with the posterior margin at more or less a right angle. In the shape of pereopod 7 present material agrees well with P. zelei Ledoyer, 1983 from Madagascar, but that species has a dactylus on male gnathopod 2 which is terminally rounded.

It would be unwise for me to erect yet another species in what may be a P. s e t i g er species complex without the opportunity to study material from a wide range of localities.

Azman & Ali (2015) synonymised P. siamensis Wongkamhaeng, Coleman & Pholpunthin, 2013 , with P. setiger Chevreux. However , in the light of the variability discussed above, this synonymisation might need to be reconsidered.

Figures

FIGURE 12.? Parelasmopus setiger Chevreux, 1901, Lighthouse Reef, Palau.

FIGURE 13.? Parelasmopus setiger Chevreux, 1901, Lighthouse Reef, Palau.

FIGURE 14.? Parelasmopus setiger Chevreux, 1901, Lighthouse Reef, Palau.