Carinartemis striatus Siriboon & Panha, 2014

Siriboon, Thanit, Sutcharit, Chirasak, Naggs, Fred, Rowson, Ben & Panha, Somsak, 2014, Revision of the carnivorous snail genus Indoartemon Forcart, 1946 and a new genus Carinartemis from Thailand (Pulmonata: Streptaxidae), Raffles Bulletin of Zoology 62, pp. 161-174 : 171-172

Carinartemis striatus Siriboon & Panha , new species

( Figs 1 , 2C , 6F, G , 7C, D , 8 G–K, Table 1)

Type material. Holotype CUMZ 6203 ( Fig. 6F ). Measurement: shell height 9.2 mm, shell width 11.4 mm, 7 whorls . Paratypes: CUMZ 6117 (5 shells; Fig. 6G ) , CUMZ 6204 (3 shells) , CUMZ 6205 (1 specimen in ethanol; Figs 2B , 7A, B , 8 G–I) , NHMUK 20130611 (2 shells) , SMF (2 shells), and ZRC (2 shells).

Type locality. Tam Kra Sae , Sai Yok, Kanchanaburi, Thailand. A limestone mountain reaching about 200 metres above mean sea level (14°6'23.5"N, 99°9'58.0"E) .

Etymology. The specific epithet from the Latin “stria” meaning “furrow”, in reference to the strong transverse ridges or radial striation on the shell surface.

Diagnosis. Carinartemis striatus , new species, can be distinguished from H. mirificus in its larger shell, higher spire, strong transverse ridges over the entire shell, subcircular aperture, broadly expanded peristome, and small parietal lamella. Whereas H. mirificus has a smaller shell, lower spire, nearly smooth shell surface, triangular aperture and a strong and triangular parietal lamella.

Compared with H. exacutus and H. sankeyi , this new species differs by having a strong peripheral keel around nearly the entire penultimate whorl, the last whorl less being inflated and much deviated from the vertical axis, and with strong transverse ridges over the entire shell. In comparison, these two species have a strong peripheral keel over less than half of penultimate whorl, and have the last whorl inflated and less deviated from vertical axis. The transverse ridges of H. exacutus disappear below the periphery of the penultimate whorl and it has two distinct parietal lamellae.

Description. Shell oblique-heliciform, white, dull, and translucent; whorls 7, spire low conical with distinct suture. Shell surface glossy, with strong transverse ridges and varices present. Embryonic shell with about 2½ whorls and smooth surface; following whorls regularly expanding. Shell periphery wide and sharply keeled around nearly the entire penultimate whorl; last whorl axially deflected. Umbilicus open and shallow. Aperture semi-ovate, peristome discontinuous, thickened, expanded and reflected. Apertural dentition of one parietal lamella ( Fig. 6F ).

Radula. Teeth arranged in anteriorly V-shaped rows, each row containing 45–49 teeth with the formula (22-24)-1-(22- 24); central tooth small, short, triangular with pointed cusp. Lateral and marginal teeth undifferentiated, unicuspid and lanceolate; lateral teeth gradually reduced in length and size with outer teeth much smaller and shorter than inner teeth ( Fig. 8K ).

Genital organs. Atrium (at) short. Penis (p) long, slender, becoming slightly broad in middle and then tapering distally. Penial sheath (ps) thin, extending about quarter of total penis length; penial sheath retractor muscle (psr) very thin, originating at atrium and body wall, inserting distally on penial sheath ( Fig. 7C ). Vas deferens (vd) slender, very long, attached to distal end of penial sheath with very thin connective tissue ( Fig. 7D ). Penial retractor muscle (pr) thin and very long, inserting distally on penis at the penis and vas deferens junction.

Internal wall of atrium generally corrugated with sparse atrial pores ( Fig. 8G ). Penial wall with pale brown penial hooks, about 1 hook/200 μm 2; hooks located on irregular trapezoidal papillae (pl). Penial hooks short (<0.04 mm in length), slightly expanding at base, tips sharp and curved towards genital orifice ( Fig. 8H, J ).

Vagina (v) short and stout. Gametolytic duct (gd) long, extending as far as albumin gland; gametolytic sac (gs) ovate. Free oviduct (fo) long, proximally large with equivalent diameter with vagina, and tapering to a smaller tube distally. Oviduct (ov) enlarged and folded; prostate gland inconspicuous and bound to oviduct. Talon (ta) small, very short and club shaped. Hermaphroditic duct (hd) bearing seminal vesicle (sv) about as long as the length from talon to branching point of seminal vesicle ( Fig. 7C ).

Proximal vaginal wall with undulated parallel vaginal folds, arched distally; transverse parallel cavity present; vaginal hooks absent ( Fig. 8I ).

Distribution. This new species was found from the limestone karst near the very famous historic site.

Remarks. Apparently rare. Recent extensive searching revealed the living animal for the first time.

Figures

Fig. 1. Distribution map of Indoartemon spp. and Carinartemis spp. Indoartemon spp (white circle): (1) Indoartemon cingalensis (Benson, 1853); (2) Indoartemon layardianus (Benson, 1853); (3) Indoartemon glacilis (Collett, 1898); (4) Indoartemon eburneus (Pfeiffer, 1861); (5) Indoartemon fuchsianus (Gredler, 1881); (6) Indoartemon bidens (Möllendorff, 1883); (7) Indoartemon tridens (Möllendorff, 1898); (8) Indoartemon laevis (Blanford, 1899); (9) Indoartemon prestoni (Gude, 1903); and (10) Indoartemon medius, new species. Carinartemis spp. (black circle): (1) Carinartemis vesperus, new species; and (2) Carinartemis striatus, new species.

Fig. 2. Living snails of: A, Indoartemon medius, new species, paratype CUMZ 5017 (shell width about 8 mm); B, Carinartemis vesperus, new species, paratype CUMZ 6201 (shell width about 10 mm); C, Carinartemis striatus, new species, paratype CUMZ 6205 (shell width about 12 mm).

Fig. 6. A, Shell of Stemmatopsis poirieri lectotype MNHN 26980; B–E, Shells of Carinartemis vesperus, new species, (B) holotype CUMZ 5019 with apertural dentition, (C, D) paratype CUMZ 6200 from Khao Kling, Khao Yoi District, Phetchaburi, and (E) specimen NMW 1955.158.25233 from Khao Yoi, Petchaburi; F, G, Carinartemis striatus, new species, (F) holotype CUMZ 6203 with apertural dentition, and (G) paratype CUMZ 6117 from Tam Kra Sae, Sai Yok, Kanchanaburi.

Fig. 7. Genitalia of Carinartemis spp: A, B, Carinartemis vesperus, new species, paratype CUMZ 6201, (A) reproductive system, and (B) insertion of vas deferens into penial sheath; C, D, Carinartemis striatus, new species, paratype CUMZ 6205, (C) reproductive system, and (D) attachment of vas deferens into distal end of the penial sheath.

Fig. 8. Internal sculpture of genitalia of Carinartemis spp: A–F, Carinartemis vesperus, new species, paratype CUMZ 6201, (A) details of atrial pore on the atrium surface, (B) high magnification of penial hooks, (C) top view of penial hook, (D) arrangement of vaginal folds with hooks, (E) high magnification of vaginal hook, and (F) radula morphology. G–K, Carinartemis striatus, new species, paratype CUMZ 6205, (G) details of atrium surface, (H) low magnification shows arrangement of penial hooks, (I) low magnification shows arrangement of vaginal folds, (J) high magnification of penial hooks, and (K) radula morphology.