Taphrenalla corona 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 : 57-60

Taphrenalla corona Pholyotha & Panha , sp. nov.

( figs 1 , 3 , 5, 10A, 11A–C, table 6)

Type material examined. Holotype: CUMZ 7191 (fig. 10A). Paratypes. Same data as holotype: CUMZ 7192 (two shells and nine specimens in ethanol) , CUMZ 7193 (21 shells) , CUMZ 7194 (one specimen in ethanol) , NHMUK (two shells) , and SMF (two shells) .

Other material examined. Limestone outcrops at Ao Luek Tai, Ao Luek District, Krabi (8°24’09.9”N, 98°44’16.3”E): CUMZ 7195 (five specimens in ethanol) . Tham Sa Yuan Thong, Ao Luek District, Krabi (8°21’44.6”N, 98°44’45.9”E): CUMZ 7196 (one shell) . Tham Phet, Ao Luek District, Krabi (8°23’33.9”N, 98°46’24.0”E): CUMZ 7197 (one shell) . Wat Khao Hua Sing, Plai Phraya District, Krabi (8°30’47.7”N 98°45’30.1”E): CUMZ 7198 (29 shells) . Tham Nalakiring Bureau of Monks, Plai Phraya District, Krabi (8°33’35.3”N 98°51’37.5”E): CUMZ 7225 (eight shells and three specimens in ethanol) . Wat Khao Phra, Phrasaeng District, Surat Thani (8°37’33.0”N 98°56’53.5”E): CUMZ 7226 (15 shells) . Tham Namlod Bureau of Monks, Phrasaeng District, Surat Thani (8°40’40.2”N 98°56’41.9”E): CUMZ 7227 (six shells) .

Figure 10 Shells. A. Taphrenalla corona sp. nov. holotype CUMZ 7191. B. T.parversa sp. nov. holotype CUMZ 7199. C. T. conformis sp. nov. holotype CUMZ 7202. D. Taphrenalla incilis sp. nov. holotype CUMZ 7207. Inset SEM image showing shell sculpture of each species.

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Figure 11 Genitalia and spermatophore. A–C. Taphrenalla corona sp. nov. paratype CUMZ 7192. A. whole reproductive system. B. internal wall of penis with penial verge. C. spermatophore; inset showing two spines located close to the sperm sac. D–F. T. parversa sp. nov. paratype CUMZ 7200. D. whole reproductive system. E. internal wall of penis with penial verge. F. spermatophore; inset showing two spines located close to the sperm sac. White arrowheads indicate the position of penial verge.

Type locality. Limestone outcrops near Than Bok Khorani, Ao Luek District, Krabi, Thailand (8°22’28.7”N 98°44’07.9”E) .

Etymology. The specific epithet “ corona ” is from the Latin word “ corona ” meaning “crown” and is in reference to the characteristic radial grooves on the shell sculpture of this genus.

Diagnosis. Shell with wide channel-shaped suture, and slightly deep and short radial grooves. Penis with thick penial sheath. Penial caecum absent. Epiphallic caecum straight. Inner sculpture of proximal penis with fine irregular longitudinal folds and then with obliquely longitudinal folds distally. Dart apparatus connected on vagina. Spermatophore with two spines on tail filament close to sperm sac.

Description

Shell (fig. 10A). Shell depressed conic, medium-sized (width up to 16.0 mm; height up to 9.3 mm) and slightly milky to brownish. Whorl 5–6; suture wide and deep groove, channel-shaped. Upper shell surface with rather strong and short radial grooves continuing from suture to inconspicuous at periphery and disappears below periphery. Radial grooves starting between whorl 3 to 4 and having 26–47 grooves at last whorl (n = 26; fig. 5). Spire slightly depressed conic; apex raised with a spire angle of about 140–155°. Last whorl barely shouldered and well-rounded at periphery. Aperture lip simple; umbilicus narrowly opened.

Genital organs (figs 11A–C). Atrium short. Penis enlarge cylindrical and same length as vagina; penial caecum absent. Inner sculpture of proximal penis with fine irregularly longitudinal penial pilasters, gradually transforming to obliquely longitudinal folds surrounding penial verge. Epiphallus slender tube, about two and a half times total penis length and smaller diameter than penis. Epiphallic caecum short, and attached with thick penial retractor muscle. Flagellum prolonged with irregular cylindrical tip. Vas deferens slim tube. Vagina prolonged, cylindrical-shaped and distal part larger diameter than proximal part. Dart apparatus located on proximal vagina away from penis joining to atrium. Spermatophore long and needle-shaped. Tail filament very long tube; region near sperm sac bearing two spines, spine close to sperm sac very small and shorter than the other.

External features ( fig. 3 ). Animal very dark gray in body colour with one creamy to pale orange stripe in middle of body running from head to caudal horn; stripe on tail wider than on body to head.

Remarks. Although the shell morphology of this new species is close to those of T. diadema and T. dalli sp. nov., its genitalia is unique. The absence of a penial caecum and presence of a thick penial sheath covering a proximal portion of penis distinguished T. corona sp. nov. from the other Taphrenalla species.

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.