Bevahites bevahensis Collignon, 1948

Ifrim, Christina & Stinnesbeck, Wolfgang, 2021, Ammonoids and their biozonation across the Santonian-Campanian boundary in north-eastern Coahuila, Mexico, Palaeontologia Electronica (a 34) 24 (3), pp. 1-62 : 6-8

Bevahites bevahensis Collignon, 1948

Figure 5A–B, G–J , Table 3

1928 Mortoniceras sp. ; Adkins, plate 34, figure 1

1948 Behavites [sic] bevahensis nov. sp.; Collignon, p. 84, plate 11 (5), figures 3, 3a, 3b

p. 1952 Texanites densinodosus ; Young and Marks, p. 480, 482-483 [not plate 1, figure 1]

1963 Bevahites bevahensis Collignon, 1948 ; Young, p. 94, plate 53, figures 1–7; text-figures 15c, 21d, 27b

1967 Bevahites bevahensis Collignon, 1948 ; Wolleben, p. 1153, plate 148, figure 4; text-figures 8a, b

Type. The holotype is the original of Collignon (plate 11, figures 3, 3a, b) by monotypy. It is from the upper Santonian of Bevaho, Madagascar, and stored in the Collections de l'École Nationale Supérieure des Mines , Paris , currently housed in the Villeurbanne campus, Université Lyon .

Material. Two specimens, CPC –2374 and –2547, from bed TPY26 .

Description. Moderately involute, with U/D between 0.30 and 0.39. Whorl section suboval; WB/WH = 0.56, with WB largest at mid-flank. Ribs moderately sinuous. One or two ribs arise from prominent, strong umbilical tubercles, although ribbing is moderately inequidistant. Ribs are moderately prorsiradiate and flex back in a wide arch to become straight and rursiradiate ventrolaterally. Bullae are located on the ribs at mid-flank, while broad, faint ventrolateral tubercles are connected to weak clavi next to the venter.

Dimensions. Table 3.

Remarks. Ribbing and whorl section readily distinguish Bevahites bevahensis from other Texanitinae . The adult stage of this species is discussed in detail by Wolleben (1967).

Occurrence. Uppermost Santonian of westernmost to central Texas, Chihuahua, Tepeyac in Coahuila, Madagascar.

Figures

FIGURE 5. Bevahites from the Tepeyac section. A–B, G–J: Bevahites bevahensis, A–B: CPC–2374; G–J: CPC–2547, both bed TPY26; C–F: Bevahites costatus coahuilaensis, C–D: CPC–2372, bed TPY27; E–F: CPC–2548, beds TPY40-46. Scale: 50 mm.