Conus (Chelyconus) manueltenorioi (Bernard M. Landau, Carlos Marques da Silva, and Antoine Heitz, 2016)

Descrizione e caratteristiche (1):

 

Description.

Shell medium-sized, squat; spire low. Protoconch unknown (not preserved in available material). Spire whorls weakly convex, bearing one narrow subsutural spiral cord placed close to the suture; first 4 teleoconch whorls weakly tuberculate. Subsutural flexure asymmetrically curved, with depth greater than width. Last whorl squat, inflated; subsutural platform narrow, very slightly concave, rounded at shoulder, weakly convex below. Base weakly constricted, bearing fine spiral ridges. Aperture straight, relatively broad, broadening further in abapical half; siphonal canal relatively short, straight; siphonal fasciole hardly developed. Outer lip attached below shoulder. Color pattern enhanced under ultraviolet light consisting of blotches and small dots.

 

Differentiation.

Chelyconus manueltenorioi n. sp. is characterized by its broad, squat shape, its weakly tuberculate early whorls, its narrow subsutural area bearing a single spiral cord placed close to the suture, and its relatively broad aperture.

Chelyconus trajectionis (Maury, 1910), from the Chipola Formation of Florida, shares the tuberculate early teleoconch whorls and the single subsutural cord, but differs in having a more elongate last whorl with a narrower aperture, and the subsutural ramp is not sunken as it is in C. manueltenorioi n. sp.

Chelyconus colombiensis (Weisbord, 1929), from the lower Pliocene Tuberá Formation of Colombia, is more similar in shape to the Cantaure species, also with tuberculate early whorls, but differs mainly in the character of the subsutural area, which is convex and not concave and sunken as in C. manueltenorioi n. sp. The outer lip in this species attaches closer to the shoulder than in the Cantaure shell, but this can be interspecifically variable. The holotype of C. colombiensis is not well preserved, and no subsutural cord is seen in the holotype (PRI 22938).

 

The genus Chelyconus is represented today by a single species on either side of the Isthmus of Panama: Chelyconus ermineus (Born, 1778), which is amphiatlantic, and Chelyconus purpurascens (G. B. Sowerby I, 1833) on the tropical eastern Pacific side. Of these, C. purpurascens is most closely similar to C. manueltenorioi n. sp. in size and shape, in having a weakly concave subsutural ramp with some spiral sculpture, and in the relatively wide aperture. The color pattern of the Cantaure shell enhanced under ultraviolet light is identical to that seen in C. purpurascens. Both of these species have tuberculate early whorls (J. K. Tucker & Tenorio, 2009; Kohn, 2014). However, this description applies only to small juvenile specimens because spire wear usually destroys these structures in older shells. Some specimens with flat spires keep them longer due to reduced erosion.

 

Etymology.

Named after Manuel Jiménez Tenorio of Cádiz, Spain, in recognition of his enormous contribution to the systematics of cone snails. Chelyconus gender masculine.

 

Distribution.

Lower–middle Miocene: Cantaure Formation, Venezuela (this paper).

 

Conus manueltenorioi

Pl. 44, Figs 1–2;

 

1. Holotype, NHMW 2013/0556/0279, mm. 52,4 x 27,9, apertural (a), dorsal (b), and lateral

 (c) views.

2. Paratype 1, NHMW 2013/0556/0425, mm. 61,5 x 36,3, dorsal (a) and apertural (b) views.

Conus manueltenorioi

Pl. 46, Figs 5–6

Conus manueltenorioi

Pl. 47, Fig. 6

 

 

 


Bibliografia Consultata

 

·         (1) - Systematics of the Gastropods of the Lower–Middle Miocene Cantaure Formation, Paraguaná Formation, Paraguaná Peninsula, Venezuela Bernard M. Landau, Carlos Marques da Silva, and Antoine Heitz