First Report of Hemipenial Variation among Some Genera and Species of Shieldtail Snakes (Serpentes: Uropeltidae) from India and Sri Lanka
Hemipenial characteristics have historically provided a wealth of comparative morphological characters for the systematic classification of snakes. However, the organs remain poorly known in many groups, particularly tropical and burrowing lineages. Here, we report on hemipenial morphology for 12 species from five genera from the family Uropeltidae: Melanophidium punctatum, M. cf. wynaudense, Plectrurus perrotetii, Rhinophis karinthandani, R. melanoleucus, R. saffragamus, R. sanguineus, Teretrurus cf. hewstoni, Uropeltis bhupathyi, U. cf. ceylanica, U. macrolepis, and U. rajendrani. Many are photographed or illustrated here for the first time. In Melanophidium, the organ is bulbous and mushroom-shaped, with the sulcus spermaticus winding through numerous convoluted folds. In Plectrurus and Teretrurus, it is simple, smooth, and conical. In Sri Lankan Rhinophis and some Uropeltis, the organ generally resembles previously described hemipenes from other species in those genera in being simple, subcylindrical, and covered in fine spines. However, a median lobular process is observed in the Indian species R. karinthandani, R. melanoleucus, and R. sanguineus, seemingly representing a novel bilobate morphology. One species, U. bhupathyi, exhibits a novel, bulbous morphology, but this may be an artifact of preservation. The hemipenes of the Uropeltidae and their sister group Cylindrophiidae resemble some typhlopoid blindsnakes more than their henophidian relatives such as pythons and boas. Whether this is due to convergence related to microhabitat, a form of sexual selection unrelated to ecomorphology, or symplesiomorphy from an ancestral snake morphology is unclear. Gross hemipenial morphology can now serve to diagnose uropeltids to the genus level or species group, though more data and comparative series are needed to determine whether other characters, such as the number and location of spines, can potentially differentiate taxa at finer scales.
Partially everted hemipenes of Melanophidium punctatum SACON/S1 in sulcate (A, C) and asulcate (B, D) view. No fixed scale bar available; organ ∼7.7 mm (∼27% of 29 mm TL; Table 1). Abbreviations: fl, lobular flounces; p, pedicel; sf, sulcal folds; ss, sulcus spermaticus.
Everted hemipenes of Melanophidium cf. wynaudense CESS 291 in photograph (A–D) and illustration (E, F). Views are sulcate (A, C, E) and asulcate (B, D, F). Scale bars in A, E, and F are 1 mm; B is 2 mm; and C and D are 3 mm. Abbreviations: fl, lobular flounces; ss, sulcus spermaticus.
Everted hemipenes (photograph [A, B] and illustration [C–E]) of Plectrurus perrotetii CESS 324 (A, C, and D) and CESS 325 (B and E). Organ is simple, cylindrical, elongate, and conical with an enlarged pedicel. Views are sulcate (A, B, D, E) and asulcate (C). All scale bars are 1 mm. Abbreviations: a, apex; b, body; p, pedicel; ss, sulcus spermaticus.
Partially everted hemipenes of two specimens of Rhinophis karinthandani, VPRS 0721121 (A–C, E) and paratype BNHS 3545 (D), showing unusual, possibly bilobate condition. No fixed scale bar available for photos; both organs ∼2 mm, ∼16–18% TL. Scale bar for drawing 1 mm. Abbreviations: il, inner lobe; ol, outer lobe; pp, apical papilla; ss, sulcus spermaticus.
Partially everted hemipenes of a paratype of Rhinophis melanoleucus (BNHS 3537; see Cyriac et al., 2020) in asulcate (A) and sulcate (B) views along with ventral aspect (C–D), showing unusual, possibly bilobate condition. Whether this is an artifact of preservation, a lobular process, or a truly distinct bilobed morphology requires additional study. No fixed scale bar available for photographs (A–C); 1 mm for illustration (D); organs ∼2.1 mm, ∼18% TL. Abbreviations: fl, basal flounces; il, inner lobe; ol, outer lobe; sp, fine lobular spines or hooks.
Photograph (A) and drawing (B) of partially everted hemipenes of Rhinophis saffragamus in partial sulcate view. No fixed scale bar available; length of everted portion of organs ∼50–75% of TL (see de Silva and Ukuwela, 2020 for extensive description of the full specimen). Abbreviations: sl, fleshy, lobular sulcal lips; sp, fine lobular spines or hooks; ss, sulcus spermaticus.
Partially everted hemipenes of Rhinophis sanguineus (VPRS 0918093) in asulcate (A, B, C) and sulcate (D) view, showing short, stout organs with median lobular processes potentially representing a bilobate condition. No fixed scale bar available for photographs (A, B); 1 mm for illustrations (C, D); organs ∼2.1 mm, ∼18% TL. Abbreviations: fl, basal flounces; il, inner lobe; ol, outer lobe; sp, fine lobular spines or hooks.
Partially everted hemipenes of Teretrurus cf. hewstoni (VPTH 0721123) in asulcate view (A–C). Organ is simple, cylindrical, elongate, and conical with an enlarged pedicel. No fixed scale bar available for photographs (A, B); 1 mm for illustration (C); organs ∼1.3 mm, ∼19% TL. Abbreviations: a, apex; b, base; p, pedicel.
Partially everted hemipenes of Uropeltis bhupathyi (SACON/S2) in lateral view illustrated (A) and photographed (B). Scale bar 1 mm; length of lower-most everted organ ∼4 mm (∼30% of 13 mm TL; Table 1). Abbreviations: a, apex; b, basal portion; p, pedicel.
Partially everted hemipenes of Uropeltis cf. ceylanica (CESS 266) in overhead (A), asulcate (B), and sulcate (C) views. Scale bars are 1 mm. Abbreviations: sp, fine lobular spines or hooks; ss, sulcus spermaticus.
Partially everted and damaged hemipenis of a roadkill Uropeltis macrolepis “mahableshwarensis” (U12; see Pyron et al., 2016) in asulcate (A) and sulcate (B) view. The damaged tissue is darkened; the remaining intact portion shows the typical “Uropeltis” morphology. Scale bars are 1 mm; organ length approximately 7.1 mm (∼44% of 16.2 mm TL). Abbreviations: b, base; fl, folds or flounces; sp, lobular spines or hooks; ss, sulcus spermaticus.
Partially everted hemipenis of the holotype of Uropeltis rajendrani (BNHS 3359), previously photographed in Ganesh and Achyuthan (2020: img. 1H–I), illustrated here in asulcate (A) and sulcate (B) views. Scale bar is 1 mm; organ is ∼3 mm, ∼23% of TL. Abbreviations: a, apex; b, basal portion; p, pedicel; sf, sulcal folds; sp, lobular spines or hooks; ss, sulcus spermaticus.
Contributor Notes
Associate Editor: D. S. Siegel.