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Turritella venezuelana
Taxonomy
Turritella venezuelana was named by Hodson (1926) [Shell is small, turreted, and rather slender. Protoconch consists of 1% small round whorls. Nuclear whorls are continuous with the nepionic whorls which are sub-medially bicarinate, with a slightly convex, long, posterior slope; anterior slope, short, steep, and slightly concave; the second nepionic whorl shows a trace of a microscopic spiral on the anterior third of the posterior slope; the later nepionic whorls develop another spiral thread on the upper third of the posterior slope; the spiral ribs are sharply elevated; the interspaces are wide and concave. The neanic and succeeding whorls of this abundant species begin to show many variations in the shape of the whorl, and in the character and spacing of the spirals. The commonest form has a rather flat tapering whorl with an overjutting beveled base sloping down sharply to the suture; the second anterior primary spiral forms the apex of the angle between the long, tapering, posterior part of the whorl and the narrow, steep, anterior slope leading down to the suture; the long posterior part of the whorl carries four elevated spirals with wide concave interspaces; the interspace between the 2 large posterior primaries is usually wider than the others; just in front of the suture on the posterior slope, there are one or two secondary spiral threads ; about the middle of the steep anterior slope there is a fairly strong spiral. The surface of the shell is usually covered with a shiny enamel. The growth lines are very inconspicuous, but are slightly
retractive on the sides and base of the whorl. The base is flattened and ornamented with numerous fine spirals.
There are innumerable variations in this species. The shape of the adult whorls varies tremendously,' even in the same individual. The larger whorls frequently become roundly convex instead of being angulated behind the anterior slope. In some specimens, secondary threads appear in some of the wide interspaces, and other threads near the sutures.
This small form somewhat resembles the much larger species, T. subgrundifera Dali 1 from the Chipóla beds, which has its nuclear whorls oblique to the axis of the shell. The inside of the shell gives very faint traces of internal lirae. ].
Sister species lacking formal opinion data
T. adela, T. agronomica, T. alcida, T. altiliroides, T. ameghinoi, T. anguillana, T. bilara, T. bilboraensis, T. biplicata, T. boycensis, T. brankampi, T. callizona, T. capensis, T. carninata, T. caseyi, T. chalybeatensis, T. chirena, T. claytonensis, T. cobbani, T. codellana, T. collazica, T. crocus, T. diastropha, T. difficilis, T. distincta, T. falconensis, T. fascialiis, T. femina, T. fischeri, T. forgemoli, T. gardnerae, T. hilli, T. jenkinsi, T. kauffmani, T. knysnaensis, T. kowiensis, T. laevissima, T. leonensis, T. lineolta, T. litharia, T. malaspina, T. mcnairyensis, T. megalobasis, T. meunieri, T. millepunctata, T. ministeri, T. molarium, T. monserratensis, T. multilinata, T. mundula, T. neusensis, T. novaesemljae, T. paraensis, T. pedroana, T. pelusae, T. perrieri, T. pirabica, T. pliorecens, T. pontoni, T. poronaiensis, T. premimetes, T. rostrata, T. rubricollis, T. soaresana, T. submortoni, T. tanaguraensis, T. trilara, T. triplicata, T. turneri, T. wagneriana, T. wasana, T. webbi, T. wiedenmayeri, T. pllanigyrata, T. conspicablis, T. chichibuensis, T. premortoni, T. waltonensis
Synonymy list
Year | Name and author |
---|---|
1926 | Turritella venezuelana Hodson pp. 32-202 figs. Pl.21 figs 4 and 8; Pl. 22, figs 1, 6 |
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If no rank is listed, the taxon is considered an unranked clade in modern classifications. Ranks may be repeated or presented in the wrong order because authors working on different parts of the classification may disagree about how to rank taxa.
†Turritella venezuelana Hodson 1926
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Diagnosis
No diagnoses are available