Conus (Hemiconus) peraratus (Cossmann, 1897)

 

 

Descrizione e caratteristiche:



Diagnosis of H. peraratus : Small biconical Hemiconus with flat-sided whorls, spire 35% of total height; below the beaded subsutural cord are up to 4 spiral cords increasing in strength downwards, the lowest being the most prominent and produced into 14 or so narrow, dentiform nodules per whorl, more distinct on the early whorls; underlying suture more or less canaliculate; another similar cord emerges from the suture on the last whorl to form a relatively inconspicuous bicarinate shoulder; protoconch small, diameter c. 500 μm., paucispiral of 1.75 whorls with an impressed suture; last whorl straight-sided, ornamented by numerous low, close, rounded spiral cords, wider than their interspaces (2).

 

Discussion of H. peraratus : This is the most abundant Hemiconus in the Cotentin and variable in height to width ratio. Typically the shoulder is somewhat angular but examples with a swollen periphery occur (Plate 5, Fig. 65). In a narrower morph from Néhou, the dentiform nodules are more pronounced, the upper part of the whorls concave and initially smooth and the spiral threads more distanced and sometimes granulated (Plate 5, Figs. 66, 67). This might well represent a different taxon except that it seems to be linked to typical H. peraratus Cossmann, 1897 by a series of intermediate forms. Broader shells with more or less granulated cords on the spire could also be considered to intergrade with H. douvillei Cossmann & Pissarro, 1901 (Plate 5, Figs. 63-64).

 

 

 

 

Hemiconus peraratus (Cossmann, 1897)

original figure after Cossmann (1897)

pl. 4 figs. 22-23

Coislin (Loire-Atlantique)

Hemiconus peraratus (Cossmann, 1897)

56. (protoconch) NHMUK PI TG 26888 (leg. B.CRAIG) Néhou

57. (protoconch) NHMUK PI TG 26889 (leg. S. TRACEY) Néhou

59. (protoconch) NHMUK PITG26896 (leg. S. TRACEY) Fresville

 

Hemiconus peraratus (Cossmann, 1897)

 

60. NHMUK PI G 15492(1) (coll. PISSARRO) Fresville

61. NHMUK PI TG 26892 (leg. B. CRAIG) Néhou

62. NHMUK PI TG 26893(leg. B. CRAIG) Néhou

63. NHMUK PI TG 26894 (leg.O. GAIN) Néhou

 

 Hemiconus peraratus (Cossmann, 1897)

 

64. NHMUK PI TG 26895 (leg. O. GAIN) Néhou

65. NHMUK PI TG 26896 (leg. S. TRACEY) Fresville

66. NHMUK PI TG 26897 (leg. O. GAIN) Néhou

67. NHMUK PI TG 26898 (leg. B. CRAIG) Néhou

 

 

 


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