Conasprella orbignyi (Audouin, 1831)

 

 

Description (1):

 

C. testä tenui, elongata , subfusiformi , transversim striatd, spird elevato-acut&, tuberculata, maculis fulyis transversim striatis.

 

Long. 5 cent. 5 mill.; larg. 2 cent.

 

Le muséum d'histoire naturelle de Paris est redevable de ce joli cône à M. Dussumier qui lui en a fait don en 1820. Il est surtout remarquable par la ressemblance que présente sa forme et la minceur de son test, avec certain cônes fossiles à spire alongée, entre autres avec le Conus antediluvianus. Il diffère beaucoup plus de toutes les espèces vivantes que j'ai vues dans les collections. Ses stries transversales, l'élévation de sa spire et sa couleur le font cependant ressembler un peu au conus strigatus de Bruguière et de Lamarck ; mais indépendemment que les tours de spire sont tuberculés, ce qui n'existe pas dans ce dernier, il est en tout plus étroit et beaucoup plus effilé en avant.

 

Le cône de d'Orbigny est long de deux pouces; sa spire occupe le quart de cette longueur; sa plus grande largeur est de huit lignes.

 

La spire qui est élevée et pointue, est composée de onze tours dont les angles, ou les bords externes, sont occupés par une série de tubercules presque perliformes; ces tours sont eux-mêmes parcourus par des stries au nombre de cinq, et leur intervalle est finement treillissé ; la coquille, dans le reste de son étendue, est entièrement couverte de stries transversales fort prononcées, très régulières et

 

Characterization (2).

Shell medium-sized, up to 41 mm. Protoconch of 3 to 3.5 whorls. Teleoconch whorls tuberculate. Spire high, stepped; outline straight to slightly concave. Sutural ramp slightly concave, ornamented with 1 increasing to 6 spiral grooves above the tubercles and with radial threads. Last whorl narrowly conical to conical or narrowly pyriform, outline straight to weakly convex at upper two-thirds and straight to weakly concave at lower one-third. Shoulder angulate, with strong tubercles and two rather narrow spiral grooves just below tubercles. Subsutural flexure shallow, gently curved. Sculpture of last whorl consists of rather strong, axially striate spiral grooves, which become narrower in larger shells. Siphonal canal often deflected to the dorsal side. Aperture very narrow.

 

Distribution (2).

Japan to the Philippines, Queensland, in 50–400 m ( Röckel, Korn & Kohn, 1995). Japan Sea, southward to the Philippines, sand and mud bottoms, 50–425 m ( Hori, 2000). Also from the Pliocene of Okinawa ( Noda, 1988), Early Pleistocene of Taiwan ( Nomura, 1935), the Pleistocene of Vanuatu ( Ladd, 1982) and the Pleistocene of Fiji ( Kohn & Arua, 1999a; Kohn & Arua, 1999b).

 

Remarks (2).

Conasprella orbignyi ( Audouin, 1831) was previously thought to be a species complex containing three subspecies ( Röckel, Korn & Kohn, 1995), but Puillandre et al. (2011) regard these subspecies as separate species, based on their genetic divergence, shell morphology and geographic variation. This separation is regarded here as justified, even though the shell morphology of some of the newly created taxa seems to overlap, particularly in C. orbignyi ( Audouin, 1831) s.s. and C. coriolisi (Röckel, Richard & Moolenbeek, 1995) .

 

Unfortunately, Puillandre et al. (2011) do not discuss fossil shells in the C. orbignyi -complex. However, based on the strong spiral grooves on the body whorl, the strong tubercles and spiral grooves on the spire and the relatively slender body whorl and spire, the studied fossil material matches C. orbignyi ( Audouin, 1831) s.s. most closely. This identification was confirmed by Rob Moolenbeek.

 

Twelve specimens were measured, eight of which show minor damage (see Table 2  ). The results of these measurements were compared to the values given by Röckel, Korn & Kohn (1995) for C. orbignyi ( Audouin, 1831) s.s., which are: NPW 4, SL 38–87 mm, RD 0.42–0.50, PMD 0.83–0.90 and RSH 0.21–0.28. The measurements in the fossil material are all near the upper limits of these values, or exceed them, with the exception of NPW and SL. The averaged values for the undamaged specimens are: NPW 3.2, SL 32.7 mm, RD 0.50, PMD 0.92, RSH 0.31. The specimens are likely not full-grown shells, as reflected by their relatively low SL. This might have caused the RD, PMD and RSH values to turn out relatively high. There is no obvious reason for the difference in NPW. Perhaps there is an evolutionary trend that has caused NPW to increase over the last 2 million years. Fossils from other localities with intact protoconchs need to be examined to confirm this. However, the fact that these values do not entirely overlap with those given for C. orbignyi ( Audouin, 1831) s.s., is considered here to be inconsequential to the species assignment of the studied material, also because of the small sample size.

 

Specimen RGM 1008311 (Anda1) was bleached to try to reveal its colour pattern, but this had no effect.

 

Noda (1988) figures a very large (SL> 80 mm), very high spired fossil specimen that matches C. orbignyi in its sculptural characters and is regarded here as thus, despite its aberrant shape and size.

 

 

Conasprella orbignyi (1)

 

Conus orbigny (Audouin 1831)

mm. 58,3 x 17,6

Filippine

[AZRC 743-01]

 

Conus orbigny (Audouin 1831) (2)

RGM 1008312. Locality Anda 3

mm. 40,8 x 11,3

 

 

 

Bibliografia