Haploptychius karenorum Man & Panha, 2022

Sian Man, Nem, Siriboon, Thanit, Lin, Aung, Sutcharit, Chirasak & Panha, Somsak, 2022, Revision of the carnivorous land snail family Streptaxidae (Stylommatophora, Achatinina) in Myanmar, with description of four new species, ZooKeys 1110, pp. 39-102 : 39

Haploptychius karenorum Man & Panha sp. nov.

Fig. 14C-E

Type material.

Holotype CUMZ 13017 (Fig. 14C ). Measurements: shell height 9 mm, shell width 11.6 mm and 7 whorls. Paratypes CUMZ 13018 (6 shells; Fig. 14D ), NHMUK (2 shells).

Type locality.

Limestone outcrops at Waiponla Hill, Hpa-an Township, Hpa-an District, Kayin State, Myanmar (16°56'7.4"N, 97°42'56.8"E).

Other material examined.

Taung Lay Cave , Hpa-an Township, Hpa-an District, Kayin State, Myanmar (17°11'40.3"N, 97°37'47.0"E): CUMZ 13019 (2 shells; Fig. 14E ) .

Diagnosis.

Haploptychius karenorum sp. nov. can be differentiated from H. heliakosus sp. nov. by having a convex spire, penultimate whorl angular and extended well beyond the diameter of the last whorl, and more axially deflected last whorl. In contrast, H. heliakosus sp. nov. possesses an elevated spire, penultimate whorl rounded, less extended beyond the diameter of the last whorl, and less axially deflected last whorl. This new species differs from H. bombax by having an angular penultimate whorl, more axially deflected last whorl, subcircular aperture, and broadly expanded lip. In comparison, H. bombax has a rounded penultimate whorl, less axially deflected last whorl, semi-ovate aperture, with thickened and slightly expanded lip. For further comparison, H. karenorum sp. nov. differs from H. burmanicus , H. blanfordi , and H. thebawi in having a more axially deflected last whorl, lower spire, penultimate whorl angular and strongly extended beyond the diameter of the last whorl, and without sinulus. The three latter species have an elevated spire, penultimate whorl rounded and slightly extended beyond the diameter of the last whorl, and less axially deflected last whorl.

Description.

Shell oblique-ovate, solid and translucent; whorls 6- 7½; spire depressed convex and with distinct suture. Embryonic shell ~ 2½ whorls with smooth surface; following whorls growing regularly and last whorl intermediately expanded. Shell surface has moderately strong radial ridges that diminish below periphery of last whorl and around umbilicus. Penultimate whorl bluntly angular and extended beyond last whorl. Last whorl compressed to flattened, axially deflected from columellar axis. Aperture subcircular; peristome thickened, expanded, and slightly reflected. Apertural dentition with one strong parietal lamella. Umbilicus widely open and deep (Fig. 14C-E ).

Etymology.

The specific name karenorum refers to the Karen people, the major ethnicity in Kayin State, Myanmar.

Distribution.

This species is known from two localities in the limestone karts of Kayin State, southern Myanmar.

Remarks.

Comparing populations from the two localities, shells of H. karenorum sp. nov. from the Taung Lay population (Fig. 14E ) have a more elevated spire and weaker parietal lamella. However, the bluntly angular penultimate whorl and oblique ovate shells are identical to the type specimens, which we consider an intraspecific shell variation. However, these two localities are quite distant from each other, and on opposite sides of the Attaran River (Fig. 1 ). Thus further, genitalia information will help determine whether they are just geographical variations.

Figures

Figure 1. Approximate sampling locations used in this study. The location name and coordinates are listed in Table 1. Historical type localities of a broad scale, such as Tavoy, Burma, Moulmein, Mergui, and Tenasserim, are not indicated on this map.

Figure 14. A, B Haploptychius heliakosus sp. nov. A paratype CUMZ 13014 from the type locality and B specimen CUMZ 13016 from Kyonknow Cave, Hpa-an, Kayin State C-E Haploptychius karenorum sp. nov. C holotype CUMZ 13017 with apertural dentition D paratype CUMZ 13018 from the type locality and E specimen CUMZ 13019 from Taung Lay Cave, Hpa-an, Kayin State.