Amphipholis linopneusti Stöhr, 2001

O’Hara, Timothy D., 2015, Enigmatic ophiuroids from the New Caledonian region, Memoirs of Museum Victoria 73, pp. 47-57 : 54-56

Amphipholis linopneusti Stöhr, 2001

Fig. 4

Amphiura crassa (in part).-- Koehler, 1904a: 83-84, pl. 15(1-2) [Non Amphiodia crassa (Koehler, 1904) ; see Stöhr, 2001].

Amphiodia crassa .-- Koehler, 1922a: 167-168, pl. 69(11).--Clark, A.M., 1970: fig. 5c-d [Non Amphiodia crassa (Koehler, 1904) ; see Stöhr, 2001].

Amphipholis linopneusti Stöhr, 2001: 319-322 , fig. 1a-h.

Material examined. -- New Caledonia. BIOCAL: stn DW44, Ride de Norfolk , 22° 47.3'S, 167° 14.3'E, 440-450 m, 30 Aug 1985: 10 ( MNHN IE.2013.16006) . -- EBISCO: stn DW2613, Plateau des Chesterfield , 19° 37'S, 158° 41.9998'E, 519-522 m, 2005: 7 ( MNHN IE.2007.7480) . -- Australia. FR0688: stn 01, east of Cape York, Queensland, Australia , 10° 29.82'S, 144° 0.38'E, 495-534 m, 1988: 14 ( AM J23292 ) . -- Papua New Guinea. BIOPAPUA: stn CP3692, Pointe Sud-Est Manus Island, 2° 10'S, 147° 19'E, 408-448 m, 2010: 1 ( MNHN IE.2012.686) . -- BIOPAPUA: stn CP3645, Tami Island , Golfe de Huon, 6° 44'S, 147° 50'E, 403-418 m, 2010: 20 ( MNHN IE.2012.319) . -- Vanuatu. Santo: stn AT122, SE Malékula Island , 16° 37'S, 168° 0'E, 567-580 m, 2006: 1 ( MNHN IE.2009.1990) .

Distribution. Fiji (260-651 m), New Caledonia and Vanuatu (440-580 m), NE Australia (495-534 m), Papua New Guinea (403-418 m), Indonesia (450-877 m), Philippines (? 42-454 m)

Remarks. This species is sexually dimorphic. The lowermost basal arm spines of males are enlarged, sometimes flattened and hour-glass-shaped, whereas on the females they are cylindrical with a blunt rounded apex ( Fig. 4). In many ways, this species is very divergent from other Amphipholis species. The disc scales are raised, with the radial shields in particular being surrounded by sunken borders. The arm spines are thick and short, almost capitate in some specimens. The single tentacle scale is large, often erect (on preserved material), hinged on the lateral arm plate but angled outward away from the mid-radius. The two oral papillae on the side of each jaw can vary in size, sometimes the inner one is larger, although it is always longer than wide and pointed proximally. The distal one is square to rectangular, typically wider than long. Unusually, the species is also epizoic on sea urchins.

Most Amphipholis species have two small tentacle scales (A.M. Clark, 1970). Exceptions include Amphipholis vitax Koehler, 1904a , (which also has atypical long narrow divergent radial shields), A. pentacantha H.L. Clark, 1915 , A. murmanica Djakonov, 1929 and A. nudipora Koehler, 1914 which have rudimentary tentacle scales on basal segments or not at all. Amphipholis tuberosa Stöhr, 2011 also has only a few small tentacle scales basally. This species has tuberculated disc plates and is very similar to Amphistigma watsonae Baker, 1979 . Finally Amphipholis loripes Koehler, 1922a was recently transferred to Amphiodia (Amphispina) by Stöhr, 2011 after spinous plates were discovered distal to the radial shields. These species do not have a homogeneous morphology. Indeed, genetic evidence (Hugall & O’Hara unpublished data) indicates that many amphiurid genera ( Amphiura , Amphipholis , Amphioplus ) are polyphyletic. We refrain from establishing a new genus for A. linopneusti until these genera are comprehensively revised.

There is also considerable morphological variation within Amphipholis linopneusti . As well as the sexual dimorphic characters, the number and shape of the other arm spines varies. There are up to seven arm spines in the BIOCAL stn DW44 lot (which contains only females). In the type series ( Stöhr 2001), arm spines varied from being elongate (up to four times as long as wide) to small and stout (two times as long as wide). The shape of the oral shield also varies from round to triangular to oval (longer than wide). More research is required to determine whether this taxon includes one or more cryptic species. The taxon is distributed throughout the Indonesian-west-Pacific region at upper continental slope and rarely continental shelf ( Koehler, 1922a) depths.