Diameza Deshayes, 1865

Maxwell, Stephen J., Rymer, Tasmin L. & Congdon, Bradley C., 2021, Resolving phylogenetic and classical nomenclature: A revision of Seraphsidae Jung, 1974 (Gastropoda: Neostromboidae), Zootaxa 4990 (3), pp. 401-453 : 420

Diameza Deshayes, 1865 [Maxwell, this paper] nomen cladi conversum

( Seraphsinae )

Figure 6A

1865 Diameza Deshayes , p. 572. Cossmann 1889, p. 95. Jung 1974, p. 32. Bandel 2007, p. 138. Caze et al. 2010, p. 426 .

Type. Ovula fragilis Defrance, 1825, p. 132 (by monotypy).

RegNum Registration Number. 678.

Reference Phylogeny. Figure 3 .

Definition. The maximum clade consisting of Diameza fragilis ( Defrance, 1825) and all species that share a more recent common ancestor with it than with Seraphs sopitus ( Brander, 1766) , Miniseraphs eratoides ( Cossmann, 1889) or Terebellum terebellum ( Linnaeus, 1758) .

Diagnosis. The shell is involute and inflated. The maximum diameter of the shell is just above the midline of height. The parietal callus is weak. The labrum is thickened and sinuous, being protocyrt on the lower part of the shell, and opisthocyrt on the upper part. The labrum extends above the apex, and there is a rudimentary basal sinus. The shell is smooth, with a few indistinct basal oblique grooves. The columella is smooth, and mostly straight near the base.

Composition. Diameza contains one species detailed herein, and belongs to the Seraphsinae , but excludes Miniseraphs and Seraphs .

Remarks. There is only one recognised member of Diameza . While closely related to Miniseraphs , the latter lacks the acute apex of Diameza . However, based on overall similarities, it is likely they both share a hitherto unknown common ancestor arising in the Thanetian, Palaeocene of Europe ( Jung 1974). While originally placed with Ovulidae Fleming , Diameza shows the rudimentary stromboidal notch and growth pattern more consistent with the Seraphsidae ( Cossmann 1904; Jung 1974). The clade Diameza Deshayes, 1865 has a restricted geological range of the Middle Eocene of Europe (Table 3).

Figures

FIGURE 3. The clade Seraphsidae Jung, 1974 derived from character analysis and contextualised with the fossil record showing the ancestral Seraphsinae and crown clade Pseudoterebellinae both new subfamilies.

FIGURE 6. Dimeza Deshayes, 1865, Miniseraphs Jung 1974 and Mauryna de Gregorio 1880. A. Diameza fragilis (Defrance, 1825), MNHN A28784, Collection de Paleontologie, Paris, length 6.9 mm (Caze et al. 2010, figs. 20A, C & E). B. Miniseraphs eratoides (Cossmann, 1889), MNHN A28785, Collection de Paleontologie, Paris, length 8.3 mm (Caze et al. 2010, figs. 20F–H). C. Miniseraphs isabella (Deshayes, 1865), MNHN A28783, Collection de Paleontologie, Paris, length 7.5 mm (Caze et al. 2010, figs. 20M–O). D. Mauryna plicata (d’Archiac & Haime, 1853), NMB H15324, length 51 mm.