Reticularia M’Coy, 1844

Carniti, Alessandro P., Porta, Giovanna Della, Banks, Vanessa J., Stephenson, Michael H. & Angiolini, Lucia, 2022, Brachiopod fauna from uppermost Visean (Mississippian) mud mounds in Derbyshire, UK, Acta Palaeontologica Polonica 67 (4), pp. 865-915 : 905-906

Genus Reticularia M’Coy, 1844

Type species:? Terebratula imbricata Sowerby, 1822 , from the upper Visean of Yorkshire, England .

Remarks.— George (1932) emended the original description of Reticularia to include lamellose spiriferides bearing dental plates and a ventral septum, with ornamentation of uniramous spines. However, he included in the genus the species Reticularia alexandri George, 1932 , which lacks a ventral septum. This led Minato (1953) to erect Georgethyris based on R. alexandri , characterised by the absence of a ventral septum and divergent dental plates. Minato (1953) also emended the description for Reticularia defining it as characterised by a ventral median septum and parallel dental plates. This left without generic assignment most species assigned to Reticularia by George (1932), characterised by a ventral median septum and divergent dental plates: R. acutiloba George, 1932 , R. lobata Muir-Wood, 1926 , R. mesoloba Phillips, 1836 ), R. bellmanensis George, 1932 , R. obtusa Sowerby, 1820 ), R. profecta George, 1932 . These species should all be included in Georgethyris if the divergent dental plates are considered to be a diagnostic character for the genus, regardless of the presence or absence of a septum. This was the view adopted by Brunton and Tilsley (1991) and Brunton and Mundy (1997: 229). The same species should be referred to Reticularia according to the view of Carter and Gourvennec (2006), who agreed with George (1932) in considering Reticularia as characterised by dental plates, regardless of their orientation, and a ventral median septum, whereas Georgethyris was defined as having “ventral interior seemingly lacking median ridge; otherwise similar to Reticularia ” ( Carter and Gourvennec 2006: 1848).

It is the authors’ opinion that species close in their morphology to Reticularia imbricata ( R. bellmanensis , R. mesoloba , and R. profecta ) should be referred to Reticularia , emended to include gently uniplicate shells with parallel to divergent dental plates and ventral median septum, while species closer to Georgethyris alexandri ( R. acutiloba , R. lobata , and R. obtusa ) should be referred to Georgethyris , emended to include transverse, strongly uniplicate to parasulcate shells with divergent dental plates and a variably developed to absent ventral median septum.