(Dautzenberg & Fischer, 1925)
Original taxon: Montacuta phascolionis.
Synonyms: compressa Philippi, coarctata Wood.
Lives in the infralittoral-circalittoral, as a commensal of the Annelid Phascolion strombus (Montagu, 1804), often together with Epilepton clarkiae (Clark, 1852) or Ondina perezi (Dautzenberg & Fischer, 1925) – see Perez, 1924. The worm Phascolion itself is nested in empty shells of some Gastropods such as Aporrhais pespelecani (Linnaeus, 1758) or Turritellinella tricarinata (Brocchi, 1814), or the Scaphopod Antalis novemcostata (Lamarck, 1818) etc.
« The form of the shell is somewhat oblong, rounded at the corners; the posterior side is not only the shorter, but is rather narrower; the dorsal margin of the anterior side being nearly straight, while the posterior has a gentle slope by which that side is a little diminished. The exterior in perfect specimens has a beautiful glossy appearance, and it was probably in the living state a semitransparent shell. » – S. V. Wood: A monograph of the Crag Mollusca vol.2 Bivalves, London 1851, p.124: Kellia coarctata.
« The form of the shell is somewhat oblong, rounded at the corners; the posterior side is not only the shorter, but is rather narrower; the dorsal margin of the anterior side being nearly straight, while the posterior has a gentle slope by which that side is a little diminished. The exterior in perfect specimens has a beautiful glossy appearance, and it was probably in the living state a semitransparent shell. » – S. V. Wood: A monograph of the Crag Mollusca vol.2 Bivalves, London 1851, p.124: Kellia coarctata.
Above and below: 120m deep, Málaga Bay, Andalucia, S. Spain. 8,7mm. Original pictures provided by A. Nappo (IT).
– (CC BY-NC-SA) –
« There is one tooth in each valve, that in the right is the larger and more prominent; behind this is the ligament, placed on an oblong kind of shelf, inclining inwards on the posterior side; the edge of this shelf is in some individuals slightly elevated above the margin, and might be mistaken for another tooth; the lines of growth are occasionally visible but no regular striae, and the impressions of the muscles are not distinguishable ». Indeed, they are.
About his Galeomma ? compressum, Philippi notices: « Apex acutus, non incurvus, parum pone medium situs. […] Margo ventralis rectus, medio aliquantulum sinuatus, hiatum ventralem angustum formare videtur. » – R. A. Philippi: Enumeratio molluscorum Siciliae… part II, Berlin 1844, p.19.