Cantellius pallidus, (BROCH, 1931)

CANTELLIUS CF. PALLIDUS ( BROCH, 1931) ( FIGS 8, 9)

E x a m i n e d m a t e r i a l: M N H N - I U - 5 8 6 3, h o s t S t y l a s t e r f l a b e l l i f o r m i s (L a m a r c k, 1 8 1 6). MNHN-IK-2015-658, 12°34.6 ′ S, 45°05.2 ′ E, 21 March 1977. MNHN-IU-2014-5873, host Distichopora violacea MNHN-IK-2015-660, 11°34.6 ′ S, 45°05.2 ′ E, 12 April 1977. TAU AR29859 View Materials GoogleMaps , host Stylaster tenisonwoodsi PC 190371, Bangka Island , 5 m, Indonesia, Università Politecnica delle Marche-DiSVA, Ancona, Italy, 16 December 2011. TAU AR29860 View Materials , host Stylaster cf. eximius, BALA 1, Siladen Islands Indonesia, 15 m, Università Politecnica delle Marche-DiSVA, Ancona, Italy, 13 December 2011 .

Description: Shell conical, four plated, externally covered by the hydroid skeleton and tissue. Sheath forming inner lamina, basis, shallow cup shape with radiating ridges and furrows reaching the centre of the basis. Orifice central, small. Scutum and tergum separated, white. Scutum triangular, basal margins curved; pit at basitergal angle; occludent margin length approximately equal to tergal margin. Occludent margin and tergal margin straight. Externally, growth ridges parallel to basal margin outline, forming teeth on occludent margin. Cavity for lateral depressor wide, shallow. Inner side with adductor ridge that varies in different specimens; articular ridge on tergal margin curved and occupying nearly entire length of margin. Tergum elongated; carinal margin about two-thirds of scutal margin with blunt rounded spur; scutal margins slightly curved, with small beak at the apex; basal margins sinusoidal; external surface with growth ridges parallel to basal margins; shallow median furrow from apex to spur base.

Remarks: The identification of MNHN-IU-5863 is based only on the morphology of scuta, because the terga are broken and cannot be used as a morphological character. In the specimens from the two species of Stylaster , there is a prominent pit at the basitergal angle and a cavity for the lateral depressor, as in C. pallidus . The apices of the terga are broken, and the wide spur might fit also to Cantellius arcuatus ( Hiro, 1938) . However, it is more likely that it belongs to C. pallidus . Cantellius pallidus is the most abundant species of Cantellius and has been recorded from 37 species of corals, whereas C. arcuatus has been recorded from only two species of corals ( Ogawa & Matsuzaki, 1992).