Perrottetia dermapyrrhosa Siriboon & Panha

Siriboon, Thanit, Sutcharit, Chirasak, Naggs, Fred & Panha, Somsak, 2013, Three new species of the carnivorous snail genus Perrottetia Kobelt, 1905 from Thailand (Pulmonata, Streptaxidae), ZooKeys 287, pp. 41-57 : 44-46

Perrottetia dermapyrrhosa Siriboon & Panha sp. n. Figs 2A3 A–C4A–C5A–G 6ATable 1

Type material:

Holotype CUMZ 5001 (Fig. 3A). Measurement: shell height 6.1 mm, shell width 7.7 mm, and with 6 whorls. Paratypes NHMUK 20130062 (2 shells), SMF 341486 (1 shell), CUMZ 5002 (2 shells).

Type locality.

Wat Tam Namsrithong, Nong Kungsi, Kalasin, Thailand, 16°48'18.0"N, 103°16'42.5"E.

Diagnosis.

Perrottetia mabillei (Bavay and Dautzenberg, 1903) can be distinguished from Perrottetia dermapyrrhosa sp. n. by its lower spire with a distinct suture. The left periphery of the penultimate whorl is shouldered and does not extend beyond the diameter of the last whorl. The aperture is triangular and a supracolumellar lamella is absent. In comparison, Perrottetia peroteti (Petit, 1841) possesses a lower spire with a distinct suture, fine transverse ridges are present and a smaller basal lamella, while upper palatal and supracolumellar lamellae are absent. Perrottetia gudei (Fulton, 1915) (syntype Fig. 3L) differs from Perrottetia dermapyrrhosa sp. n. in its lower spire, the second parietal lamella being smaller and shorter than the first lamella and an upper palatal lamella that is usually present ( Petit 1841, Bavay and Dautzenberg 1903, Kobelt 1906, Fulton 1915). In Perrottetia dermapyrrhosa sp. n. the genital atrium is long, the penial sheath reaches about two- thirds of the penial length and the gametolytic duct and sac do not extend as far as the albumin gland. The penial hooks are more scattered and, in the introverted penis, are housed in deep ovate depressions; vaginal hooks are present. In comparison, Perrottetia gudei possesses a short genital atrium and penial sheath, and the gametolytic duct and sac extend as far as the albumin gland; the penial hooks are denser than in Perrottetia dermapyrrhosa sp. n., and each hook is situated on a small papilla ( Schileyko 2000, fig. 1015D).

Perrottetia dermapyrrhosa sp. n. differs from Perrottetia aquilonaria sp. n. in its larger shell, which is less deviated from the vertical axis. A sinulus sensu Schileyko (2000) is absent; the first and second parietal lamellae are connected, and a bifid columellar and supracolumellar lamellae are absent. In comparison, Perrottetia dermaphyrrhosa sp. n. possesses a long atrium and vagina, and a penial sheath with a club shaped distal penis. The length of vas deferens that enters the penis distally is longer. The penial papillae are located in hollows, the penial hooks are much more scattered, and vaginal hooks are present.

Description.

Shell oblique-heliciform, white and translucent; whorls 6, spire conical, suture distinct; shell surface glossy, with transverse ridges that diminish below the periphery; embryonic shell large, consisting of about 2 whorls with smooth surface, following whorls regularly expanding; shell periphery rounded, last whorl axially deflected; two deep and short longitudinal furrows present; umbilicus narrow (Fig. 3A); aperture subcircular, peristome discontinuous, thickened and expanded; apertural dentition with a large transverse first parietal lamella, with second parietal lamella adjoined at right angles; one upper palatal lamella, one small palatal lamella, one large basal lamella, one long subcolumellar lamella, one large strong columellar lamella and one small supracolumellar lamella (Fig. 3B).

Radula: Teeth arranged in anteriorly V-shaped rows, each row contains 29-31 teeth with formula (14-15)-1-(14-15); central tooth very small and triangular with a pointed cusp; lateral and marginal teeth undifferentiated, unicuspid and lanceolate; lateral teeth gradually reducing in length and size; outer teeth much smaller and shorter than inner teeth (Fig. 6A).

Genital organs: Atrium (at) long and slender; proximal penis (p) long, slender and with solid muscular penis sheath extending distally beyond penis sheath as a narrow tube; penial sheath (ps) reaching about two-thirds of total penis length, penial sheath retractor muscle very thin (psr), originating at atrium and inserting distally on penial sheath (Fig. 4A); vas deferens (vd) passes through about one-sixth of penial sheath length before entering into penis distally (Fig. 4B); penial retractor muscle (pr) thin and very long, inserting at penis and vas deferens junction; internal wall of atrium generally smooth with numerous pores (Fig. 5A); penial wall with scattered and pale brown penial hooks, about 3 hooks/200 µm 2 (Fig. 5C), and hooks located on conical papillae surrounded by deep ovate hollows; penial hooks of small size (<0.04 mm in length), expanding at base, tip sharp and curved towards genital orifice (Fig. 5E); vagina (v) short, stout, about one third of total penis length; gametolytic duct (gd) a long tube not extending as far as albumin gland, gametolytic sac ovate (gs); free oviduct (fo) very short, oviduct (ov) enlarged and folded; prostate gland inconspicuous and bound to oviduct (Fig. 4A); talon (ta) small, very short and club shaped; hermaphroditic duct (hd) bearing long seminal vesicle (sv) about one and half times longer than the length from talon to branching point of seminal vesicle (Fig. 4C); vagina wall with a corrugated fold and pale brown vaginal hooks, about 8 hooks/200 µm 2, hooks small (<0.03 mm in length) with pointed tip slightly curving away from genital orifice (Figs 5F, G).

Animal: Live specimens exhibit yellowish-red reticulated skin, and reddish tentacular retractor muscles are visible through the semi-transparent body (Fig. 2A).

Etymology.

The specific epithet “dermapyrrhosa” is derived from the Greek “derma” meaning “skin” and “pyrrhos” meaning "red or yellowish-red".

Distribution.

This species is known only from the type locality, which is an isolated limestone hill reaching about 300 meters above mean sea level, and which is surrounded by the Korat Plateau.

Remarks.

Up to now, the only description of the reproductive system of a Perrottetia species was that of Perrottetia gudei from Vietnam in which the presence of streptaxid vaginal hooks were recorded for the first time, but without being figured ( Schileyko 2000).