Megerlia King 1850

• Main Authors: Simon, Eric, Logan, Alan, Zuschin, Martin, Mainguy, Jerome, Mottequin, Bernard
• Format: Other/Unknown Material
• Language: unknown
• Published: Zenodo 2016
• Subjects: Biodiversity; Taxonomy; Animalia; Brachiopoda; Rhynchonellata; Terebratulida; Kraussinidae; Megerlia; Faroe Islands
• Online Access: https://doi.org/10.5281/zenodo.5613665; http://treatment.plazi.org/id/039287FE5D3AFF83FA8652B2FF5D7081

The genus Megerlia King, 1850 The main question of this paper is “to be or not to be Megerlia ”. The type species of this genus is Megerlia truncata (Linné, 1767). The original material described by Linné as Anomia truncata apparently consists of two dried specimens (as indicated in the Catalogue of Type specimens of the University of Uppsala: n°1907a and n°1907b) and should be Norwegian specimens (“ Habitat in Pelago Norvegico Supra corallia ” Linné, 1767; p. 1152, n° 229). However, the presence of this species off Norway was not mentioned by Logan (2007) or Hiller et al . (2008). The species was not found in northerly latitudes such as the Irish coasts by Massy (1925), Norway by Wesenberg-Lund (1939), the North Sea (Cori, 1933) and the Faroe Islands (Thomsen, 2001). In the 19th century Megerlia species were not recognized along the British coasts (Forbes & Hanley 1850, 1853). The original Linnaean specimens may have come from another area in the eastern Atlantic or even from the Mediterranean Sea. The current genus description provided by Lee & MacKinnon (2006, p. H2245) stresses the large foramen which is often abraded (considered submesothyrid to amphithyrid), the disjunct deltidial plates and the tuberculate internal valve floors. No cardinal process is developed. Crural bases are present and attached to the inner sides of socket ridges. Descending branches join the cardinalia with the posterior part of the ring of the loop. The brachidium is typically bifurcate (see MacKinnon & Lee, 2006, fig.1312) and a complete ring is built; this is unique among Kraussinoidea. SEM observations show in detail the development in M . truncata and interpretation of the earliest growth stages is here discussed again. The smallest specimen collected from Anzio has a width of 1.4 mm (Pl.1, Figs. 1a, 1b). This specimen is slightly biconvex. The tip of the beak is abraded but the submesothyrid foramen is still intact on its dorsal side. The dorsal valve is smooth and the ventral valve presents some rare tubercles ...