Jeanclaudella umbriensis ( Conti & Fischer, 1981 ), 2025

Jeanclaudella umbriensis ( Conti & Fischer, 1981) new comb.

Fig. 1A–J View FIGURE 1

v* 1981 Aaleniella umbriensis Conti & Fischer , p. 141, figs 7–10.

v 1984 Aaleniella umbriensis Conti & Fischer , p. 138, pl. 2, figs 11a–c, 12.

Material. Holotype MPUR MAC5 A , Paratype MPUR MAC5 B. Case Canepine ( Martani Mountains , Umbria, central Italy), lower Bajocian, Stephanoceras humphriesianum Zone .

Description. The shell is small (max height 3.2 mm; width 2.5 mm), with trochiform, slightly cyrtoconoidal shape and composed of five whorls. The protoconch is poorly preserved and probably slightly wider than 0.2 mm. The first two teleoconch whorls are distinctly and evenly convex. Subsequently the whorl surface becomes rapidly concave while the periphery becomes sharply carinate, and another, less marked spiral keel appears in subsutural position. The suture runs in a groove edged adapically by the peripheral keel and abapically by the subsutural keel. The last whorl is about 0.70 of the height of the shell. The base is convex and somewhat inflated, with a small umbilicus. The aperture is rounded-quadrangular. The peristome is provided with a thin parietal inductura. The columellar lip is simple and weakly arched. The outer lip is thin and slightly angulated at the end on the peristome of the peripheral carina. The ornament of the early shell consists of marked, rather prosocline and slightly prosocyrt collabral ribs which are separated by wider interspaces. On the last whorls, the collabral ribs can become less prosocyrt and less sharp on the median part of the whorl surface. They form nodes at the intersection with the peripheral and subsutural keels. The nodes become less prominent to almost obscure on the peripheral keel of the last whorl. The base is ornamented with about ten, sharp, thin, widely and subequally distributed spiral threads. The periaxial part of the base and the umbilical region lack of spiral threads and bear barely distinct collabral riblets. These riblets end at the most adaxial spiral thread where they form small nodes. The growth lines are prosocline and prosocyrt on the surface of the whorls and widely opisthocyrt on the base.

Remarks. The holotype shows the apical region smoothened by erosion and the peristome strongly fragmentary. In the paratype the peristome is more complete. The shape of the protoconch is not clearly recognizable due to poor preservation. However, what can be seen in the apical region of the holotype indicates that the protoconch was probably only slightly wider than 0.2 mm ( Fig. 1I View FIGURE 1 ). Comparisons with the other congeneric species are discussed below.