Phaedusa filicostata filicostata (Stoliczka, 1873)
“This species is very closely allied to Cl. javana, Pfr., but the latter has the whorls, particularly the middle ones, somewhat higher, the transverse costulation is a little finer, and more crowded, the palatal plaites are fewer, two according to Küster, three or four according to E. v. Martens; it also appears to have the two labial plaits stronger. I do not know any other species with which the Penang shell can be compared. It appears to be extremely rare; out of three specimens found only one has the aperture with the margins perfectly well developed.” (Stoliczka, 1873)
Stoliczka (1873) original descriptions on Clausilia (Phaedusa) filicostata – “Cl. Testa fusiforme turrita, apice sensim attenuata, subrimata, tenui, palide cornea; anfractibus 10 ad 11, lente convexiusculis, sutura simplici junctis, as duturam filiforme marginatis atque infra marginem paulum contractis, transversim oblique dense costellatis, antepenultimo vix latiore quam penultimo, ultimo versus aperturam paululum contracto; apertura ovate subtrigona, postice, (aut supra), subangulata, peristomate expanso, undique libero, plica, supera tenui, haud usque ad marginem peristomatis interni extensa, intus in fauce rapide evanescente, columellari approximata, fortiori, valde obliqua; plicis palatibus circiter decem, supera longissima, a margine distante, duabus vel tribus sequentibus multo brevioribus, caeteris brevissimis, omnibus inter so irregulater dispositis.”
Loosjes (1953) descriptions on Phaedusa filicostata filicostata – “Shell turreted-fusiform, whorls regularly and slowly tapering into the apex, delicatem pale horn-coloured; whorl 10-11, each whorl with a distinct thread near the shallow suture, sculptured with oblique and close-set ribs, antepenultimate whorl almost as wide as the penultimate one, the last whorl somewhat contracted near the aperture. Aperture ovate, subtriangular, peristome expanded, clear of the preceding whorl. Lamella superior small, scarcely extending as far as the peristomal margin, its inner end quickly disappearing. Lamella inferior strong, rather oblique: about ten plicae palatals, the top one, at some distance from the suture, is longest; the second and the third are much shorter, the others are very short and irregularly placed.”
Clausilia (Phaedusa) filicostata – “Long. 21.2, lat. 4.4; long. Apert. cum perist. Paulo imperfecto 4.8, lat. 3.6 mm; specim. Secundi apert. cum perist. Perfecto 5.3 longa et 4 mm lata.” (Stoliczka, 1873); Phaedusa filicostata filicostata – “Length 21.2, diam. 4.4 mm; aperture: height 4.8 (peristome damaged), width 3.6 mm.” (Loosjes, 1953)
Type locality – “Penang” (Stoliczka, 1873)