Taphrenalla alba Pholyotha & Panha, 2021

Pholyotha, Arthit, Sutcharit, Chirasak, Tongkerd, Piyoros, Jeratthitikul, Ekgachai & Panha, Somsak, 2021, Integrative systematics reveals the new land-snail genus Taphrenalla (Eupulmonata: Ariophantidae) with a description of nine new species from Thailand, Contributions to Zoology 90 (1), pp. 21-69 : 67-69

Taphrenalla alba Pholyotha & Panha , sp. nov.

( figs 1 , 3 , 13C, 15, table 6)

Type material examined. Holotype: CUMZ 7217 (fig. 13C). Paratypes. Same data as holotype: CUMZ 7218 (12 shells and 22 specimens in ethanol) , CUMZ 7219 (13 specimens in ethanol) , NHMUK (two shells) , and SMF (two shells) .

Other material examined. Limestone outcrops at Khlong Thom Nuea, Khlong Thom District , Krabi (7°55’47.9”N 99°16’23.3”E): CUMZ 7220 (six shells) . Limestone outcrops at Ao Luek Tai , Ao Luek District, Krabi (8°24’09.9”N, 98°44’16.3”E): CUMZ 7221 (four specimens in ethanol) . Limestone outcrops near Than Bok Khorani, Ao Luek District, Krabi (8°22’28.7”N 98°44’07.9”E): CUMZ 7222 (one shell), CUMZ 7223(10 shells and four specimens in ethanol), and CUMZ 7224 (five specimens in ethanol) . Tham Nalakiring Bureau of Monks, Plai Phraya District, Krabi (8°33’35.3”N 98°51’37.5”E): CUMZ 7228 (two specimens in ethanol) . Wat Khao Phra, Phrasaeng District, Surat Thani (8°37’33.0”N 98°56’53.5”E): CUMZ 7229 (one specimen in ethanol) .

Figure 15 Genitalia and spermatophore of Taphrenalla alba sp. nov. specimen CUMZ 7223. A. whole reproductive system. B. internal wall of penis with penial verge. C. spermatophore; inset showing two spines located close to the sperm sac.

Type locality. Wat Tham Seua (Tiger Cave Temple), Mueang District, Krabi, Thailand (8°07’32.9”N, 98°55’27.1”E) .

Etymology. The specific epithet ‘ alba ’ is from the Greek word ‘ albus ’ meaning ‘white, whitish’, and refers to the characteristics of the shell having a white line or white subsutural band below the suture.

Diagnosis. Suture shallowly impressed and with white subsutural band. Epiphallic caecum short and bent at tip. Penial caecum short. Inner sculpture of proximal penis with very soft longitudinal folds then transition to small cuboidal pilasters distally. Dart apparatus located at vagina and penis junction. Spermatophore with two spines on tail filament close to sperm.

Description

Shell (fig. 13C). Shell globosely depressed, medium-sized (width up to 18.5 mm; height up to 10.6 mm) and reddish-brown. Whorls 5–6; suture shallowly impressed and with narrow whitish subsutural band. Upper shell surface smooth and without radial grooves. Spire conic; apex raised with a spire angle of about 126–144°. Last whorl well-rounded at periphery. Aperture lip simple; umbilicus narrowly opened.

Genital organs (fig. 15). Atrium short. Penis cylindrical and nearly one and a-half times total vagina length; penial caecum present. Internal sculpture of proximal penis with thin longitudinal folds then transformed to small cuboidal penial pilasters in middle and surrounding penial verge in distal penis. Epiphallus slender tube, slightly longer than total penis length. Epiphallic caecum short and bent at the tip, and penial retractor muscle connected near tip. Flagellum slightly long (about half-length of epiphallus) with blunt tip. Vas deferens small and tube-shaped. Vagina prolonged and cylindrical-shaped. Dart apparatus located at junction between vagina and penis. Gametolytic sac elongate bulbous; gametolytic duct long and tube-shaped. Spermatophore elongate and needle-shaped. Tail filament very long tube; region close to sperm sac bearing two spines; furthest spine from sperm sac large and longer than the other.

External features ( fig. 3 ). Animal very dark gray in body colour with three milky yellow stripes running from head to caudal horn. One stripe at middle of the body and the other two above foot sole.

Remarks. Taphrenalla alba sp. nov. is similar to T. zemia sp. nov., but can be distinguished by having a reddish-brown shell with narrow whitish subsutural band, whereas T. zemia sp. nov. has a yellowish-brown shell and without subsutural band. Furthermore, the dart apparatus of T. alba sp. nov. is located at the vagina and penis junction, whereas in T. zemia sp. nov. it is located on vagina away from the vagina and penis junction.

Figures

Figure 1 Map showing the sampling sites of the 11 Taphrenalla species along Southern Thailand.Each colour of the distribution range follows the phylogenetic tree of all Taphrenalla species in fig.3.

Figure 3 A representative ML tree showing only the Taphrenalla clade.The synopsis of the radial groove on shell sculpture, genitalia showing location of dart apparatus, and live specimens of Taphrenalla spp. Results of species delimitation analyses based on the COI gene using ABGD and PTP.Black circles represent nodes with both ML (when Ē 70%) and BI (when Ē 0.95) support.White circles represent nodes with ML BS support but no BI PP support (when <0.95). Each clade colour refers to the distribution range in fig. 1.