Vexillum michelottii
Creators: name: Harzhauser, Mathias
name: Landau, Bernard
Publisher: name: Zenodo
Year: 2021
Subjects: Biodiversity
Taxonomy
Animalia
Mollusca
Gastropoda
Neogastropoda
Costellariidae
Vexillum
Vexillum michelottii

description: Vexillum michelottii (Hörnes, 1852)
Figs 4N, 16I 1 –I 2, J 1 –J 2, K 1 –K 2, L 1 –L 2, M
* Mitra Michelottii Hörnes — Hörnes 1852b: 105, pl. 10, figs 30a–b.
[Mitra] Michelottii Hörnes — Auinger 1871: 8.
[Callithea] Michelottii M. Hoern.—Hoernes 1880: 125.
cf. Mitra (Callithea) Michelottii M. Hoernes— Hoernes & Auinger 1880: 87, figs 11a–c.
Mitra michelottii Hörnes — Toth 1948: 412.
V [exillum]. (U [romitra].) michelottii (Hörn.) — Sieber 1958a: 153.
Type material. Lectotype (designated herein): NHMW 1851 /0013/0001, SL: 20.3 mm, MD: 5.4 mm, Baden (Austria), illustrated in Hörnes (1852b, pl. 10, figs 30a–b), figs 4N, 16I 1 –I 2. Paralectotype: NHMW 2020 /0088/0001, SL: 19.8 mm, MD: 4.7 mm, Baden (Austria), figs 16 J 1 –J 2.
Additional material. NHMW 1869 /0001/0249, SL: 26.5 mm, MD: 7.3 mm, Möllersdorf (Austria), figs 16L 1 –L 2; NHMW 2020 /0089/0001, SL: 25.1 mm, MD: 7.3 mm, Möllersdorf (Austria), figs 16K 1 –K 2; NHMW 1875 /0009/0007, SL: 15.3 mm, MD: 4.3 mm, Lăpugiu de Sus (Romania), illustrated in Hoernes & Auinger (1880, pl. 10, figs 11a–c), fig. 16M; NHMW 1874 /0024/0003, 2 specimens, Baden (Austria); NHMW 1869 /0040/0035, Hrušovany nad Jevišovkou (Czech Republic), NHMW 1862 /0039/0009, 2 specimens, Rudice (Czech Republic), NHMW 1854 /0035/0098, 5 specimens, Lăpugiu de Sus (Romania).
Revised description. Shell large, slender fusiform, with high spire. Protoconch multispiral, high conical, of three smooth, weakly convex whorls (height: 730 μm, diameter: 550 μm). Teleoconch of nine convex whorls, with periphery at mid-whorl or slightly below, separated by deeply incised suture. Axial sculpture on early teleoconch whorls of about ten prominent, convex, weakly opisthocline, widely spaced axial ribs, crossed by deep spiral groove close below adapical suture, forming subsutural band. Adapical tips of axials form nodes on subsutural band. Subsutural band may split into two or three narrow-spaced spiral cords by intercalation of secondary spiral grooves. Spiral cords appear between third to fifth teleoconch whorl below subsutural band, forming nodes or beads at intersections with axial ribs and grooves in axial interspaces. Number of spiral cords variable due to intercalations of secondary cords. Last whorl convex, moderately constricted at base. Axial sculpture weakening on base and fasciole, replaced by about 10 to 12 spiral cords, some extending from columellar folds. Aperture elongate, moderately narrow; columellar callus indistinct. Columella with three folds, weakening abapically. Outer lip thin, with about 11 to 15 long, delicate lirae within. Siphonal canal long, weakly deflected, with very shallow siphonal notch.
Shell measurements and ratios. SL: 15.3–26.5 mm, MD: 4.3–7.3 mm; AA: 23–30°, SL/MD: 3.4–4.1, AL/AW: 4.7–5.6, AH/S: 2.1.
Discussion. Vexillum michelottii is a rather polymorphic species concerning the spire angle and especially the sculpture on fully grown specimens. The sculpture ranges from rectangular nodulose to densely beaded depending on a variable number of intercalations of secondary spiral cords. Nevertheless, all available specimens display identical sculpture on early teleoconch whorls and have only three columellar folds. Therefore, we consider all specimens to represent a single species. The specimen from Lăpugiu de Sus, discussed by Hoernes & Auinger (1880) as “variety” of V. michelottii, has numerous healed fractures from repeated attacks by crabs or other predators (Fig. 16M). The aberrant outline and sculpture is probably pathological.
Palaeoenvironment. The localities Baden and Möllersdorf belong to the Baden Formation suggesting middle neritic settings with up to 250 m water depth (Hohenegger et al. 2008).
Distribution in Central Paratethys. Badenian (middle Miocene): North Alpine-Carpathian Foredeep: Hrušovany nad Jevišovkou (Czech Republic) (Hoernes & Auinger 1880); Vienna Basin: Baden, Möllersdorf (Austria), Rudice (Czech Republic) (Hoernes & Auinger 1880); Făget Basin: Lăpugiu de Sus (Romania).
description: Published as part of Harzhauser, Mathias & Landau, Bernard, 2021, An overlooked diversity-the Costellariidae (Gastropoda: Neogastropoda) of the Miocene Paratethys Sea, pp. 1-70 in Zootaxa 4982 (1) on page 52, DOI: 10.11646/zootaxa.4982.1.1, http://zenodo.org/record/4921842