Phylladiorhynchus pusillus

Phylladiorhynchus pusillus (Henderson, 1885)

(From Schnabel & Ahyong 2019)

Galathea pusilla Henderson, 1885: 407 (Twofold Bay, Australia, 275 m).— Henderson, 1888: 121, pl. 12, figs. 1, 1a, 1b (Twofold Bay, Australia, 275 m).— Whitelegge, 1900: 185 (off Bondi, New South Wales, 91 m).— Grant & McCulloch, 1906: 49, pl. 4, figs. 5, 5a (part, Port Phillip Heads, Victoria).

Phylladiorhynchus pusillus.— Davie, 2002: 66.— Poore, 2004: 238, fig. 66b (compilation, key).— Poore et al., 2008: 22 (SW Australia, 95–439 m) (part).— Baba et al., 2008: 176 (compilation, in part).— Rowden et al., 2010, tab. 3 (in part).— Schnabel & Ahyong, 2019: 329, figs. 10-12 (selection of lectotype, southeastern, southern and western Australia and northern New Zealand, between 10 and 274 m).

Not Galathea pusilla.— Thomson, 1899: 193, pl. 21, fig. 7 (Whanganui, Cook Strait, Paterson Inlet, 14.6 m) (= P. australis Schnabel & Ahyong, 2019).— Chilton, 1906: 267 (Channel Islands, Auckland, 46 m) (= P. australis Schnabel & Ahyong, 2019).— Grant & McCulloch, 1906: 49 (part, Mast Head Island specimen = P. spinosus Schnabel & Ahyong, 2019).— Chilton, 1911: 303 (New Zealand) (= P. australis Schnabel & Ahyong, 2019).— Borradaile, 1916: 92 (off Three Kings Islands and off North Cape, 183– 128 m) (= P. australis Schnabel & Ahyong, 2019).— Hale, 1927: 80 (South Australia, 75 fathoms) (= P. australis Schnabel & Ahyong, 2019).

Not Phylladiorhynchus pusillus.— Miyake & Baba, 1967: 234, fig. 6 (East China Sea, 102–196 m) (different species, undetermined).— Haig, 1973: 282 (S of Cape Everard (Victoria), S and SW of Mt Cann (Victoria) and off St. Helens Point, Tasmania, 110–183 m) (= P. nui Schnabel & Ahyong, 2019).— Baba, 1991: 486–487, fig. 4e, f (different species, undetermined).— Baba et al., 2009: 287–289, figs. 263, 264 (different species, undetermined).— Lee et al., 2019: 730, figs. 3, 4 (different species, undetermined).

Not Phylladiorhynchus cf. pusillus.— Ahyong, 2007: 42, fig. 20B, 22. (= P. nui Schnabel & Ahyong, 2019).

Records requiring verification:

Galathea pusilla.— Guiler, 1952:36 (D’Entrecasteaux Channel, Tasmania).—Miyake, 1965: 635, fig. 1044 (no record).— Tirmizi, 1966: 175, fig. 1.— Zarenkov, 1968: 177, fig. 22 (Victoria, Australia, 110 m).— Lewinsohn, 1969: 116 (no record).

Phylladiorhynchus pusillus.— Baba, 1969: 4 (Sagami Bay, 200–300 m).— Baba, 2005: 201, 305 (key, synonymies, Kei Islands and Japan (Sagami Bay and W of Nagasaki), 146–549 m).

Diagnosis (modified from Schnabel & Ahyong 2019). Rostrum lateral margins convex; subapical spines present. Carapace with 4 epigastric spines of which outermost may be present as a granule and much smaller than inner pair (rarely with 6 spines); anterior mesogastric ridge not medially interrupted; anterior metagastric ridge scalelike, medially interrupted. Pleonal tergite 3 usually without posterior transverse ridge. Thoracic sternite 3 anterior margin convex, median projection absent. Antennular article 1 with 5 spines: distomesial spine over-reaching lower distolateral spine, slightly to distinctly overreached by upper distolateral and first lateral spines. Antennal article 1 mesial process not reaching level of second lateral antennular spine; article 2 distolateral and distomesial spines subequal; article 3 with distinct distomesial spine. Flexor margin of Mxp3 merus with one prominent spine only. P2–4 dactylus extensor margin without upright spines at bases of movable spines.

Genetic data. COI and 16S, Table 1.

Distribution. After the complete redescription by Schnabel & Ahyong (2019), the species is found along the southeastern, southern and western Australia and northern New Zealand, between 10 and 274 m.

Remarks. Schnabel & Ahyong (2019) provided a complete description of the species, with a comparison with other species. As these authors pointed out, P. pusillus shows a certain variability in the number of epigastric spines, recommending caution in the use of this character. The species is very close to P. poeas, from French Polynesia (see the differences under the Remarks of P. poeas).