Mathilda margaritula O. Semper 1865
Creators: name: Harzhauser, Mathias
name: Landau, Bernard
Publisher: name: Zenodo
Year: 2023
Subjects: Biodiversity
Taxonomy
Animalia
Mollusca
Gastropoda
Littorinimorpha
Mathildidae
Mathilda
Mathilda margaritula

description: Mathilda margaritula Semper, 1865
Figs 25B–K
* Mathilda margaritula Semper —Semper 1865: 343, pl. 13, figs 5–5a.
Mathilda margaritula O. Semper —de Boury 1883: 118.
Mathilda margaritula O. Semp. — Boettger 1902: 154.
Mathilda margaritula Semp. —Vetters 1910: 155.
Mathilda (M [athilda].) margaritula Semp. —Sieber 1958: 139.
Mathilda (Mathilda) margaritula Semper —Sieber 1960: 265.
Mathilda granosa (Borsoni [sic]) var. gemmulata Semper —Kecskemétiné K̂rmendy 1962: 87, pl. 10, fig. 4 [non Mathilda gemmulata Semper, 1865].
Mathilda monilis Semper, 1865 — Bałuk 2006: 196: pl. 7, fig. 3 [non Mathilda monilis Semper, 1865].
Type material. Lectotype (designated herein): NHMW 1868 /0001/0549, SL: 4.8 mm, MD: 1.7 mm, Lăpugiu de Sus (Romania), Fig. 25E. Paralectotypes: NHMW 1868 /0001/0549a, SL: 4.0 mm, MD: 1.7 mm, Lăpugiu de Sus (Romania), Figs 25B 1 –B 2. NHMW 1876 /0011/0098, SL: 3.7 mm, MD: 1.5 mm, Lăpugiu des Sus (Romania), Figs 25C 1 –C 2. NHMW 1868 /0001/0549b, SL: 4.8 mm, MD: 1.7 mm, Lăpugiu de Sus (Romania), Fig. 25D. NHMW 1868 /0001/0549c, SL: mm, 4.8 MD: 1.8 mm, Lăpugiu de Sus (Romania), Figs 25F 1 –F 2. NHMW 1868 /0001/0549d, SL: 4.8 mm, MD: 1.8 mm, Lăpugiu de Sus (Romania), Fig. 25G.
Illustrated material. NHMW 1858/0047/0039a, SL: 4.3 mm, MD: 1.6 mm, Sedlec (= Porzteich) (Czech Republic), Figs 25H 1 –H 2. NHMW 1866/0001/0912, SL: 4.3 mm, MD: 1.7 mm, Niederleis (Austria), Figs 25I 1 –I 2; NHMW 1858/0047/0039b, SL: 4.2 mm, MD: 1.5 mm, Sedlec (= Porzteich) (Czech Republic), Fig. 25J. NHMW 1858/0047/0039c, SL: 2.6 mm, MD: 1.2 mm, Sedlec (= Porzteich) (Czech Republic), Fig. 25K.
Revised description. Small, slender, robust turritelliform shell; apical angle ~20°. Protoconch multispiral, of about 2.5 smooth whorls, heterostrophic, nucleus just exposed, tilted at angle of about 120°. Teleoconch of six subcylindrical whorls separated by deeply impressed, suture. Sculpture of three strongly raised primary spiral cords: S1 slightly weaker, recessed; S2 forming periphery; S3 placed at some distance above suture, equal in strength to S2. Forth spiral cord appears just above suture on third whorl largely covered by subsequent whorl. Axial sculpture of about 25 raised axial lamellae forming marked, cancellate sculpture with prominent rounded tubercles developed at intersections. Base strongly angulated, almost flat, sharply delimited by double peribasal cord, with weak periumbilical cord. Aperture small, subcircular. Outer lip simple, crenulated by edge of spiral cords. Columella nearly straight. Columellar callus forming narrow rim. No parietal callus.
Discussion. Mathilda granosa (Borson, 1821), from the Burdigalian of the Colli Torinesi (Italy), differs in its weaker subsutural cord and the keel-like mid-cord (see Pavia 1976: pl. 1, figs 2a–2b; Landau et al. 2013: 303, pl. 52, fig. 4) [note that Mathilda granosa sensu Landau et al. (2011: pl. 22, fig. 3) is Mathilda quadricarinata (Brocchi, 1814) according to Sacchetti et al. (2023)].The extant to Pliocene Mediterranean Mathilda gemmulata Semper, 1865 differs in its more slender shell, the more incised suture, the more pronounced mid-whorl angulation and the wider sutural ramp.
Paleoenvironment. Offshore clays in middle to outer neritic settings. At the Niederleis section, sediment and biota from coastal and lagoonal environments not exceeding 30 m water depth were documented (Mandic et al. 2002).
Distribution. Only known from the Langhian equivalent of the Badenian in the Central Paratethys Sea.
Central Paratethys Sea. Badenian (Middle Miocene): Korytnica Basin: Korytnica (Poland) (Bałuk 2006); Vienna Basin: Niederleis (Austria), Sedlec (= Porzteich) (Czech Republic) (hoc opus); Pannonian Basin: Várpalota (Hungary) (Kecskemétiné K̂rmendy 1962); Făget Basin: Coşteiu de Sus, Lăpugiu de Sus (Semper 1865; Boettger 1902).
description: Published as part of Harzhauser, Mathias & Landau, Bernard, 2023, The Architectonicidae and Mathildidae (Gastropoda, Heterobranchia) of the Miocene Paratethys Sea-victims of the Miocene Climatic Transition, pp. 1-74 in Zootaxa 5370 (1) on page 51, DOI: 10.11646/zootaxa.5370.1.1, http://zenodo.org/record/10147814