Cryptogemma timorensis, (TESCH, 1915)

CRYPTOGEMMA TIMORENSIS ( TESCH, 1915) View in CoL

( FIG. 8L–P)

† Pleurotoma timorensis Tesch, 1915 View in CoL . Timor. Pliocene.

† Pleurotoma ktolemandoënsis K. Martin, 1933 View in CoL . Ktolemando. Miocene.

Ptychosyrinx timorensis teschi Powell, 1964: 291 View in CoL (22– 853), pl. 223, figs 5, 6. 759 m, north-west off Sipadan Island, Borneo.

Type locality: Pliocene of Timor Island .

Remarks: This species corresponds to PSH 14 of Puillandre et al. (2012).

Protoconch commonly eroded, with PD = 1–1.2 mm and PL = 1.3–1.675 mm and number of whorls varying from four to 4.5.

The radula is medium short, ~ 2.5 mm in length (0.2 of AL), formed of 45 transverse rows of teeth. Marginal teeth are 162–172 µm long (mean 168 µm, N = 5, or 1.35% of AL), duplex. Anterior (inner) one-third of the tooth length is solid, medium broad in dorsal view, lanceolate; in posterior two-thirds the major and accessory limbs are broadly bifurcating, the accessory limb with a clear constriction and bent at about half tooth length, nearly the same length as the major limb. The central formation has a short and obtuse cusp and lateral inconspicuous flaps with indistinct lateral and anterior margins. The posterior margin is thickened and uninterrupted along its length ( Fig. 7I).

The type of this species is a fossil specimen from Timor island ( Indonesia /Timor Leste) described by Tesch (1915), and Martin (1935) described another similar specimen from Buton island ( Indonesia) as Pleurotoma ktolemandoënsis , without reference to the work of Tesch. However, Martin (1935) also recognized the affinities between Pleurotoma timorensis and Pleurotoma ktolemandoënsis . Finally, Robba et al. (1989) synonymized Pleurotoma ktolemandoënsis with Pleurotoma timorensis . Powell (1964) described the subspecies Ptychosyrinx timorensis teschi based on an extant specimen, which Sysoev (1996) elevated to species rank. The argument by both authors for separating the fossil species from the extant species was the ‘much broader’ shell of the extant Ptychosyrinx timorensis teschi specimen. Examination of the morphological variability of the sequenced specimens shows that the dimensions and shape of fossil specimens are close to the inferred average breadth of the species; some specimens show a broader aperture and a taller last whorl than others, despite having the same number of teleochonch whorls. The results of the LDA show that Pleurotoma timorensis and Ptychosyrinx timorensis teschi fall within the variability of the sequenced specimens. The broader last whorl and the generally larger size (~ 30–55 mm) are characteristic for C. timorensis when compared with C. praesignis .

List of COI diagnostic sites (position: character state): [73: G; 214: G; 334: G; 511: G].

Distribution: Found from the western Indian Ocean to the central Indo-Pacific ( Fig. 4C), from a depth of ~300 to ~ 1200 m ( Fig. 5). Curiously, this species has not been found in New Caledonia, despite considerable sampling effort in this region.