(Vinassa de Regny, 1900)
Description - Add description
Guscio grande, molto spesso, ellitico obovato, tutto scabroso, con pori circulari, profondi, assai radi, regolari, alternanti. Capo con grosso e robusto corno, lungo ed ottuso. Torace chiuso da una calotta convessa irregolarmente perforata, e munita di grandi appendici molto larghe ed acute, un poco flessuose.
Larghezza: mm. 0.15; altezza sensa appendici: mm. 0.18; altezza totale: mm. 0.37.
Miocene di Montegibio.
|Vinassa de Regny 1900|
Remarks: Although Vinassa de Regny's generic assignments of his three species listed above imply that his forms have three feet, our examination of samples from Montegibbio and other Mediterranean Neogene localities convinces us that his T. golbosa, T. elongata and A. hirta are conspecific with L. bipes, and that he made the unwarranted assumption that one foot was broken off of his illustrated specimens. On the other hand, our re-examination of Sicilian assemblages confirms Riedel's (1959) earlier conclusion that Stöhr's Pterocanium bibrachiatum was based on three-footed specimens from which one foot had been broken off. Of the three conspecific names employed by Vinassa de Regny that could be used for this species, we have selected elongata because its illustration is of a specimen most nearly typical of this species. Specimens from the Mediterranean Neogene are quite similar to those of the tropical Pacific. They have two robust, bladed feet and often a delicate, lamellar abdomen.
|Sanfilippo et al 1973|
Description: Outer shape of cephalis including apical spine conical, about 50 µm in width. Inner form of cephalis spherical or subspherical in all growth stages. Thorax subspherical or campanulate, 150 µm in diameter. Thoracic wall with rough surface and nodes on each nodal point of lattice. Nodes become large in mature specimens. Two feet stout and tribladed, more than 350 µm in length. Peristome slightly constricted. Basal aperture is almost circular, 75-80 µm in diameter. Irregular lattice structure developed below thorax in mature specimens.
Remarks: This species differs from other species of this genus in having two feet.
Occurrence: Loc. B83, siliceous clay at Lat. 0° 58' S, Long. 18° W, depth 5,359 m (Recent). Reg. nos. IGUT HN601804, 601904, 602021.
Internal spicule of theoperid type; D extends downward into the base of one foot; two L also extending into thoracic wall but without forming protrusions outside shell wall. Another foot situating at the ventral side of the sagittal plane is free from all internal skeleton.
This species has a quite peculiar relationship between the arrangement of two feet and the internal skeleton. Such a type of skeletal protrusion is somewhat similar to Jurassic species of the genera Ares De Wever, 1981, Turanta Pessagno and Blome, 1982, and Parares Takemura, 1986. The ventral foot of this species is, however, not a prolongation of V in contrast to those of the three genera.
|Sugiyama and Furutani 1992||