Calcinus sirius Morgan, 1991

Calcinus sirius Morgan, 1991 View in CoL

( Figs. 3A–D View Figure 3 , 4 View Figure 4 )

Calcinus sirius Morgan, 1991: 899 View in CoL , figs. 49–55 [Norfolk and Lord Howe Is. Middleton and Elizabeth Reefs; 2–22 m]. — Asakura, 2002: 30 [comparison specimens, paratypes from Norfolk and Lord Howe Is]. — Springthorpe and Lowry, 1994: 91 [AM, paratype specimens: Lord Howe Is. Middleton and Elizabeth Reefs; 2–22 m]. — Ahyong, 2015: 423 [Meyer and Raoul Is., Kermadec; 10–27 m]. — Myorin, 2021: Internet [NSW, Solitary Islands, photographs by Ian Shaw]. — ALA, 2021b and OZCAM, 2021b: Internet databases, specimens of Calcinus sirius View in CoL in Australian Museums [EA, same as in Morgan, 1991, with an additional record in WA, probably an error, see herein distribution and Fig. 4 View Figure 4 ].

Calcinus latens View in CoL . — Heller, 1865: 88 [in part, Sydney, 2 females, SL1.8, 2.1 mm, 1 ovigerous female, SL 3.2 mm, 2 specimens, missing most appendages, not removed from shells, NHMW 19434]. According to McLaughlin and Dworschak (2001: 155) these 5 specimens are C. cf. sirius Morgan. Not View in CoL C. latens ( Randall, 1840) View in CoL .

Calcinus tibicen View in CoL . — Heller, 1865: 87 [in part,Sydney, 1 juvenile, SL= 0.92 mm, NHMW19588].According to McLaughlin and Dworschak (2001: 154), this juvenile is possibly C. sirius Morgan. Not View in CoL C. tibicen ( Herbst, 1791) View in CoL .

Color photographs examined (Photographer Ian Shaw). Solitary Islands , Eastern Australia, depth 8–15 m, 26 February 2017, North Solitary Island (approximately -29.9275 153.3910, Fig. 3A View Figure 3 ); 13 May 2020, North West Solitary Island (approximately -30.0178 153.2713, Fig. 3B View Figure 3 ); 18 February 2019 ( Fig. 3C View Figure 3 ), 9 May 2019 ( Fig. 3D View Figure 3 ), and 4 October 2019, South Solitary Island (approximately -30.2055 153.2669) GoogleMaps .

Affinities. Overall this species is similar to C. shawi sp. nov., with the following differences: dactyl of left larger chela (male) approximately as long as upper margin of palm, instead of noticeably shorter (× 0.55) as in C. shawi sp. nov.; upper margin of left larger palm (in male) with row of low tubercles, instead of having 7 blunt spines in C. shawi sp. nov.; ventral margin of dactylus and propodus of P3 with greater development of setae than on P2 but not forming a brush of setae, whereas in C. shawi sp. nov. the setation density is similar on P2 and P3.

Live color ( Fig. 3 View Figure 3 ). Shield cream, with darker orange anterior and anterolateral margins. Ocular peduncles pink to violet on proximal half, grading to paler distally without thin cream band at base of corneas; corneas black with large white spots.Distal antennular peduncles and flagella orange. Antennal peduncles and f lagella orange. Chelipeds with fingers and palm cream to pale orange with a few minute scattered red dots; carpus and merus deep orange with white at tip of spines and tubercles. P2 and P3 uniformly orange with minute scattered red dots but without reticulation or spots, dactylus deep orange, propodus deep orange proximally fading to paler distally, carpus and merus pale orange or orange.

Distribution ( Fig. 4 View Figure 4 ). Australia, New South Wales (Solitary Islands), Tasman Sea (Norfolk and Lord Howe Islands, Elizabeth and Middleton reefs), and New Zealand, Kermadec Islands (Meyer and Raoul Is.); 2– 27 m. Probably also Sydney, from Heller’s specimens of C. latens and C. tibicen in the NHMW, tentatively assigned to C. cf. sirius by McLaughlin and Dworschak (2001: 154, 155). A record from WA in ALA (2021b) and OZCAM (2021b) databases (South of Perth, shallow water near Penguin Island, -32.30833 115.69333, AM P.42071) is probably an error for C. dapsiles (see Fig. 4 View Figure 4 ).

Remarks. The color photographs examined for the present study were taken at a depth of 8–15 m in the Solitary Islands (North, Northwest, and South), about 5–10 km offshore in EA. According to the photographer, Ian Shaw, this species is commonly seen throughout the year. Its geographic limit has been greatly extended by Ahyong (2015) to the East, to Kermadec Is. Poupin and Lemaitre (2003) had speculated that C. sirius could reach Rapa I., still more to the East ( Fig.4 View Figure 4 ), if the live coloration of C. sirius and C. aff. sirius were shown to be the same. The present study has shown that this is not the case, and that C. sirius and C. shawi sp. nov. have different distinctive coloration. Possibly, the latter new species evolved from the former by allopatric speciation.For the time being C. sirius appears to live in shallow waters (2–27 m; never reported during the numerous deep-water expeditions organized off eastern Australia), whereas C. shawi sp. nov. lives deeper (100 m; not found in shallow waters also surveyed during BENTHAUS campaign). However, as reported in this study for C. dapsiles , known from 0 to 102 m, the depth range of species of Calcinus can be wide and depth distributions of the species are still not known accurately because of the vagaries of collections and too fragmentary data.

The live color photographs of C. sirius make it also possible to remove the doubt of a potential synonymy between C. anani (and sibling C. fuscus ) with C. sirius suggested by Poupin and McLaughlin (1998: 11) and Asakura (2002: 34–35), the latter author indicating that “it is highly probable that C. anani [also C. fuscus ] and C. sirius are conspecific.However, until the living coloration of the ambulatory legs of C. sirius can be observed, this problem cannot be resolved”. The color photographs examined herein confirm that no reticulations are seen in live color of C. sirius and that it is distinct from C. anani and its sibling-species C. fuscus .