Neithea attockensis Cox, 1935
COX, L. R. 1935. The Triassic, Jurassic, and Cretaceous Gastropoda and Lamellibranchia of the Attock District. Memoirs of the Geological Survey Of India. Paleontologia Indica [New Series], 20 (Mem. 5): 1-27, pls. 1, 2. [p. 20, pl. 2, figs. 17-20]
1935 Neithea attockensis Cox, 1935
L. R. Cox, 1935, plate 2.
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«Material.— About 14 right valves, mostly incomplete, and 5 left ones (K23/714, K24:/765, K24/770, K24/772, K24/778; G. S. I. Type No. 15,655, 15,656, 15,657, 15,658). The specimen represented in figs. 17a, b (G. S. I. Type No. 15,655) is selected as holotype.
Specific characters.— Of medium size for the genus, the height slightly exceeding the length; right valve well inflated, left valve slightly concave. Right valve ornamented with six main ribs, in the interspaces between which three subequal ribs of secondary strength usually occur; occasionally, however, there may be four secondary ribs in one or more of the interspaces, in which case one is usually less prominent than the other three. There is no symmetry in the arrangement of the interspaces in which more than three ribs occur. Fine, regular, concentric threads cross the interspaces. The lateral areas have a faint radial ribbing. Auricles of moderate size, subequal, mooth. Left valve with 23-26 radial ribs, including the small ones near the lateral margins.
Dimensions.— The measurements of the holotype are as follows:-
Remarks.— In four of the right valves in which all the ribs could be counted the numbers present in the interspaces were as follows:— 3-3-3-4-3, 3-3-3-3-3, 4-3-3-3-4, 3(?)-4-4-3-4. In the well-known species N. quinquecostata (J. Sowerby), which this species closely resembles, as few as three ribs may occasionally occur in one of the interspaces, but the usual number is four or more. According to Woods [1] the ribs in the left valve number from 27-35 exclusive of the small ones near the lateral margins, so that the total number is appreciably larger than in the species now described.
The following species, like the present one, normally have three ribs in each interspace: N. regularis (Schlotheim), N. coquandi (Peron) (shawi, Pervinquière) and N. quadricostata (J. Sowerby). N. regularis is typically an Upper Senonian species, but according to Gillet [2] it may occur so low as the Cenomanian; both its main ribs and the secondary ones in the interspaces are wider and less prominent than in the form now described. In N. coquandi, from the Cenomanian of northern and western Africa, the auricles are much smaller, while the two lateral ribs in each interspace are narrower and less prominent than the median one. N. quadricostata is characterised by its unusually large auricles. Localities.— One mile 5º S. of E. of Burjianwala Laman (33° 39' : 72° 18'). East of Sujhanda, very close to village (33º 45' 30" : 72° 5'). About half a mile south of the same village. Bank of the Indus river, about 1½ miles west of the same village. Hill-slope 1½ miles south-west of Garhiala (33° 44' 30" : 72º 8').»
[1] P. 206, (1903).
[2] P. 117, (1924). LESLIE REGINALD COX, 1935
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«The morphological similarity between N. matsumotoi and Neithea attockensis Cox, 1935, from the Albian of India may offer another taxonomic problem, but any conclusion is now difficult, since that species is represented by an poorly preserved specimen.»
HAYAMI, I. & M. NODA. 1977. Notes on the morphology of Neithea (Cretaceous pectinids) with taxonomic revision of japanese species. Transactions and Proceedings of the Palaeontological Society of Japan [N. S.], 105: 27-54, pls. 5, 6. [p. 47]
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«N. attockensis L. R. Cox, 1935 (pp. 20 and 21, pl. 2, figs. 17-20) from the Albian of Attock district, India shows a strong similarity to N. gibbosa; the specimens of the former species are however much smaller and seem to be more convex than those of the latter, and unfortunately the preservation state is poor, so that no definite conclusion can be reached without the original material.»
DHONDT, A. V. 1973. Systematic revision of the subfamily Neitheinae (Pectinidae, Bivavia, Mollusca) of the European Cretaceus. Mémoires du Institute Royal des Sciences Naturelles de Belgique, 176: 1-101, pls. 1-5. [p. 58]
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«Neithea attockensis Cox, 1935, from the Albian of Attock district of India, is related to the present species [Neithea matsumotoi Hayami, 1965], in which, however, the lateral areas are more clearly ornamented and the umbonal region of the right valve is more prominent, and the secondary ribs are generally weaker and more numerous.»
HAYAMI, I. 1965. Lower Cretaceous marine pelecypods of Japan, part I. Memoirs of the Faculty of Sience, Kyushu University, [Serie D - Geology], 15 (2): 221-349, pls. 27-52. [p. 299]
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