Gosseletina microstriata, Ketwetsuriya & Karapunar & Charoentitirat & Nützel, 2020

Ketwetsuriya, Chatchalerm, Karapunar, Baran, Charoentitirat, Thasinee & Nützel, Al- Exander, 2020, Middle Permian (Roadian) gastropods from the Khao Khad Formation, Central Thailand: Implications for palaeogeography of the Indochina Terrane, Zootaxa 4766 (1), pp. 1-47 : 16

Gosseletina microstriata sp. nov.

( Fig. 13 )

Etymology. From Latin micro, meaning small, and Latin stria, meaning furrow, referring the tiny spiral ornaments.

Holotype. ESKU-19-LP 29 .

Paratypes. Two specimens: ESKU-19- LP 5, 14.

Dimensions (mm): ESKU-19- LP 5: height = c. 3.8; width = c. 4.4. ESKU-19- LP 14: height = 2.2; width = 2.2. ESKU-19- LP 29: height = 7.3; width = 8.3.

Type locality and stratigraphical range. Erawan Hill, Chong Sarika sub-district, Phatthana Nikhom district, located about 13 km east of Lopburi Province, Central Thailand ( Fig. 1 ), Khao Khad Formation, Saraburi Group, Middle Permian, Roadian.

Description. Low-spired, globose shell, medium-sized, comprising c. 4.5 whorls; apex obtuse; spire distinctly elevated; body-whorl broad and inflated, covering approximately 80% of the entire height; whorls rapidly increasing; whorls distinctly convex; whorl surface with numerous very thin, faint spiral threads; whorls embracing at periphery; selenizone broad, situated high on whorl, above periphery, flush with whorl surface or very slightly convex, ornamented as on whorl face; suture impressed but shallow; base rounded; aperture unknown.

Remarks. Gosseletina microstriata sp. nov. differs from other Gosseletina species in several aspects. G. aspeniana ( Girty, 1927) (Early Carboniferous, USA) is with faint spiral threads but differs by its whorl profile with distinctly convex whorl face above selenizone. G. permiana Batten, 1989 (Permian, USA) has a coarser spiral ornament and deeper sutures. G. nodosa Batten, 1966 a (Early Carboniferous, England) has subsutural axial riblets and lacks a spiral micro-striation. G. portlockiana ( de Koninck, 1843) (Early Carboniferous, Europe) has a stronger spiral striation ( Batten 1966 a). G. johnsoni Thein & Nitecki, 1974 is more slender and has a cancellate ornament in subsutural position. G. callosa ( de Koninck, 1843) (Carboniferous, Belgium), the type species of Gosseletina , lacks spiral ornament ( Knight 1941). G. persimplex ( Girty, 1915) (Pennsylvanian, USA) lacks spiral ornament and is more low-spired ( Hoare 1961). G. subglobosa (Hall in Miller, 1877) (Early Carboniferous, USA) has a coarser spiral ornament. G. spironema ( Meek & Worthen, 1866) (Pennsylvanian, USA) has a coarser spiral ornament and prosocyrt folds on whorl face above selenizone ( Kues & Batten 2001).

Figures

FIGURE 13. Gosseletina microstriata sp. nov., A–E, ESKU-19-LP 29, holotype. Scale bars represent: 2 mm (A–C); 1 mm (D–E). Arrows indicate the presence of selenizone.

FIGURE 1. Geological map of the study location at Erawan Hill, Chong Sarika sub-district, Phatthana Nikhom district, located about 13 km east of Lopburi Province, Central Thailand.