Himantura menoni Sahni & Mehrotra, 1981
(Fig. 4 J-R)
Himantura menoni Sahni & Mehrotra, 1981: 83, pl. 3, fig. 9A.
REFERRED SPECIMENS. — Three isolated antero-lateral teeth under the specimen numbers BIOPS/CUP/KP-41, 42 and 43. LOCATION AND HORIZON. — Middle Miocene greyish coarse sandstone gravelly lag bed of Chhasra Formation at Palasava site, Kutch, Gujarat.
DESCRIPTION
Specimens BIOPS/CUP/KP-41, 42, 43 are small teeth and high crowned rhombic in shape in occlusal view (Fig. 4 J-R). The crown of the tooth is divided into labial and lingual zones by the presence of a prominent transverse crest. The labial face of the crown is convex, shallow, a median hollow is present, crown enameloid is ornamented with wrinkles (Fig. 4K, L, Q). The lingual face of the crown is concave and a prominent median lingual ridge is present. However, the labial faces of the crowns are ornamented by irregular pits and wrinkles (Fig. 4J, K, M, N, P, Q). The labial visors are wide and nearly semi-circular to subangular in outline, and the lingual visors are narrow and angular. Median lingual ridge separates the lingual faces into two equal parts which are smooth and concave. The roots of the teeth are strong, lingually arched, bilobate and each root lobe is separated by a deep median groove (Fig. 4J, L, M, O, P, R). Labial part of the root is depressed, while the basal face of the root is nearly flat and triangular in shape.
REMARKS
Himantura menoni has earlier been reported from the late Miocene Tapar locality of Kutch, India (Sharma et al. 2021), late Miocene of Baripada Beds of eastern India as Dasyatis menoni (Sahni & Mehrotra 1981; Sharma & Patnaik 2013) which was later re-assigned to the genus Himantura (Andrianavalona et al. 2015). The present teeth resemble the female teeth as they are devoid of pointed transverse crest that bend towards the rear side (also see Kocsis et al. 2018; Sharma et al. 2021). Teeth of the genus Himantura were earlier reported from middle to late Eocene of Egypt (Underwood et al. 2011), Morocco and Pakistan (Case & West 1991; Adnet et al. 2007, 2010) from the Rupelian of Pakistan and Oman (Thomas et al. 1989; Adnet et al. 2007), Miocene of deposit of Northwestern Madagascar (Andrianavalona et al. 2015), from the Pliocene of Italy (Cappetta & Cavallo 2006). Himantura is also reported from the early Miocene of Brazil (Aguilera et al. 2017), late Miocene of Borneo (Kocsis et al. 2018), from the Pliocene of Italy (Cappetta 2012) and is also known for its wide distribution in Indo-Pacific region (also see Borsa et al. 2013; Andrianavalona et al. 2015; Weigmann 2016; Borsa 2017). The present day biogeographic distribution of the genus Himantura is in the Indo-Pacific region includes the coast of India and Madagascar (Borsa et al. 2013; Andrianavalona et al. 2015; Weigman 2016; Borsa 2017; Sharma et al. 2021).
Publication Date: 2022-12-14