Szabó János szerk.: Fragmenta Mineralogica Et Palaentologica 20. 2002. (Budapest, 2002)

50 JAITLY, A. K. & SZABÓ, J. Class Gastropoda CUVIER, 1797 Subclass Neritomorpha GOLIKOV AND STAROBOGATOV, 1975 Order Cycloneritimorpha BANDEL & FRYDA, 1999 Superfamily Neritoidea RAFINESQUE, 1815 Family Neritidae RAFINESQUE, 1815 Genus Bhujnerita n. gen. Type species — Bhujnerita hhattii n. sp. (see below). Name — Composed of from the name of town Bhuj, the administrative centre of Kachchh and from reference to the family, containing the new genus. Diagnosis — Small-medium sized form of Neritidae with rather thick-wailed, subauriform shell, composed of about two, rapidly expanding post-protoconch whorls. Protoconch itself globular and convolute, without observable ornament. Whorls with wide, almost horizontal ramp, abaxially delimited by rounded angle. Periphery bearing strong carina, more or less covered on spire whorl(s). Suture feebly impressed and running usually high on peripheral carina of previous whorl. Base convex and bearing strong keel, running nearly parallel and close to sharp-edged columellar lip on adult shell. Narrow, flat or feebly concave outer face between basal keel and columellar lip. Moderately wide, concave plate narrows aperture in roughly 60° angle backwards from peristomal plane. Peristome tangential, growm-lines prosocline and feebly prosocyrt both on whorls and base. Outer lip sharp, outward tapering. Presence of parietal callus uncertain. Strength of growth lines variable but usually marked. Remarks — The morphologically closest genera are those which have shells with wide subsutural ramp: Lissochilus ZlTTEL, 1882; Tracbynerita KlTTL, 1894; Delphinulopsis LAUBE, 1868 and Platychilina KOKEN, 1892. The latter three genera are much older, mainly Triassic, and possess heavy ornament of sparse nodes. Only one of them (Platychilina) bears a comparable basal carina along the inner lip and an apemiral plate also deeply behind the plane of the peristome, however, the characteristic mode of coiling, tending to be disjunct, cfeinguishes it doubtless from Bhujnerita n. gen. Lissochilus is a genus, contemporary with Bhujnerita n. gen. and the relationship seems likely. The most prominent difference appears in the shape of the complete shells: Lissochilus is globular with subcircular peristome but Bhtjnerita n. gen. has a shell tending to be auriform and a peristome, axially depressed. Further a^stinctive characters are around the peristome in Bhujnerita n. gen.: the presence of the basal carina along the inner lip; the reduced size or lack of a callus (extending widely over the base in Lissochilus) and the prominent concavity of the apertural plate, being flat in Lissochilus. Bhujnerita hhattii n. sp. (Figure 2) Holotype - BHU2001 1 6; Figure 2: 1-6 Type locality — Khadir Island, Kachchh, western India. Type strata — Hadibadhang Shale Member of Khadir Formation, Bathonian. Species name — From the name of our helpful friend, Mr. P. H. BHATTI, Bhuj, Kachchh. Diagnosis — See that of Bhujnerita n. gen. Material — Four shelly specimens of different state of preservation. Measurements H HL HP D WP AA AL BHU2001I 6 13.0 11.5 10.5 13.5 11.0 140° BHU2001I 7 10.5 10.0 9.5 12.0 10.0 145° BHU2001I 60 10.5 9.5 9.5 12.0 10.0 — Abbreviations to measurements: H = total height; HL = height of last whorl; HP = height of peristome; D «= diameter of last whorl; WP = width of peristome; AA = apical angle; AL = coiling angle of last whorl (if different from apical angle). Description — The ramp is slightly concave on the juvenile shell portion but later becoming flat. Only a narrow subsutural belt remains concave also on the adult parts because of upward bending of the shell. Similarly, the shell belt between the ramp angle and the peripheral carina is concave as a whole in the beginning but becoming feebly convex on the adult shell part and the concavity confines close to the peripheral carina. "Whole visible shell part between the peripheral and the basal carina is convex, disregarding a narrow concave belt along both keels, respectively. The narrow shell surface (outer face) between the basal keel and the angular edge of the columellar lip is flat in the beginning then becoming feebly concave with the growth. This surface and the basal carina itself seem to develop from the second half of the penultimate whorl as it is visible