Poraster superbus (Möbius, 1859)

Mah, Christopher L., 2023, A new species of Astrosarkus from Western Australia including new Mesophotic occurrences of Indian Ocean Oreasteridae (Valvatida, Asteroidea), Memoirs of Museum Victoria 82, pp. 143-165 : 157-160

Poraster superbus (Möbius, 1859)

Oreaster superbus Möbius, 1859: 5 ; Bell 1884: 81.

Oreaster productus Bell 1884: 74

Pentaceros superbus Sladen 1889: 345 ; Simpson and Brown 1910: 51; Brown 1910: 33.

Pentaceros indicus Koehler 1910: 110 .

Poraster productus Döderlein, 1916: 438 Poraster superbus Döderlein, 1916: 440 ; 1936: 364; Humes and Cressey 1958: 395; Clark and Rowe 1971: 34, 54; Bruce 1974: 485; Jangoux 1984: 280; A.M. Clark 1993: 317 (checklist with synonymies); Kogure and Igei 2013: 33; Marsh and Fromont 2020: 432

Poraster superbus var. bengalensis Döderlein, 1936: 367

Diagnosis. Monotypic, as for genus.

Comments. Occurrences of P. superbus have been observed from Madagascar indirectly, primarily from records of various parasitic and associated crustacean species (e.g. Humes and Cressey, 1958; Bruce, 1974). Uncertainty was reflected by Clark and Rowe (1971), who qualified its occurrence in Madagascar and east Africa with a “?”, as well as by Marsh and Fromont (2020), who listed the species as present on the north-east coast of Africa but not further south. Multiple specimen records as well as imagery from iNaturalist confirm its presence in the Madagascar region.

Most recent accounts of Poraster reflect a single, wideranging species, P. superbus . The synonymy, however, reflects at least four morphotypes throughout its range. Two of those species, P. superbus var. benegalensis Döderlein, 1936 and Poraster productus (Bell, 1884) display small abactinal and carinal tubercles/spination compared to Poraster indicus ( Koehler, 1910) and P. superbus itself. These latter two variants are apparently distinguished by the extent of superomarginal spination. Of the specimens examined, E47401 is more consistent with the indicus variant, whereas E45289 is more consistent with the description by Möbius (1859).

Few data are available on the biology of P. superbu s. This species has been reported feeding on shelly sand with its stomach everted on a sand-encased solitary ascidian, as well as scavenging on moribund echinoids (Marsh and Fromont, 2020). Several parasitic and associated crustacean species have been reported (e.g. Humes and Cressey, 1958, Bruce, 1974). One observation ( Derleisereiter, 2020) shows an individual in a spawning position with arms suspending the disk into the water column above a sandy substrate.

Occurrence. North-east coast of Africa to Zanzibar . Bay of Bengal to New Caledonia , southern China and north to Japan. 20– 55 m. iNaturalist observations also show this species in Sri Lanka (Laccadive Sea) , Singapore and in the Seychelles.

New records. Madagascar, Mozambique Channel , 30 m. Tanzania, Mergui Archipelago, Burma, Andaman Sea to 96 m (new depth record) .

Material examined. USNM E 45289 Mozambique Channel , Madagascar, Indian Ocean, - 15.87° S, 44.38° E, 30 m. Coll . R / V Anton Bruun, International Indian Ocean Expedition, 19 Oct 1964. 1 dry spec . R= 16.2 cm, r=4.7.

USNM E 47401 Lord Loughborough Island , Mergui Archipelago, Andaman Sea, Burma. 10.62° N, 97.57° E, 96 m. Coll . R / V Anton Bruun , International Indian Ocean Expedition, 24 March 1963. 1 dry spec . R=21.4, r=6.5.

USNM E47402 East of Phuket Island , Thailand, Andaman Sea, Indian Ocean. 7.92347° N, 98.8363° E, 16– 20 m. Coll . RV Gallardo , Fifth Thai Danish Expedition, 15 Feb 1966. 2 dry specs . R=20.0 r=5.0; R=22.0 r=4.8.

CASIZ 30883 South Tanzania, Menai Bay, - 6.408° S, 39.4106667° E, 18 m. Coll. Coral Reef Research Foundation, 3 Feb 1996. 1 wet spec .

MNHN-IE-2007-1000, South of Cape Saint Sebastian , Madagascar, Indian Ocean. - 12.61717° S, 48.505° E, 59–60 m. Coll. Bouchet, Puillandre and Richer, MIRIKY. 29 June 2009. 1 wet spec. R =14.4, r=5.2.

MNHN-IE-2007-1090, South of Cape Saint Sebastian , Madagascar, Indian Ocean. - 12.62733° S, 48.43317° E, 60–63 m. Coll. Bouchet, Puillandre and Richer, MIRIKY. 29 June 2009. 2 wet specs. R =4.3, r=1.2; R=1.3, r=0.6.