Late Oligocene - Miocene non-lunulate sand dollars of South America: Revision of abertellid taxa and descriptions of two new families, two new genera, and a new species Author Mooi, Rich Author Martínez, Sergio A. Author Del Río, Claudia J. Author Ramos, Maria Inês Feijó text Zootaxa 2018 2018-01-05 4369 3 301 326 journal article 31071 10.11646/zootaxa.4369.3.1 34826a1d-7146-4d75-9585-b226f798ffdb 1175-5326 1135772 97CAA2FC-F3CC-407B-8768-2BB9DE037C86 Iheringiella patagonensis (Desor in Agassiz & Desor, 1847 ) Figures 1 , 4 . Diagnosis . As for the family and genus. We note, in addition, that I. patagonensis is the only South American scutelliform clypeasteroid in which test length and width are nearly equal (all other such species being significantly wider than long). Occurrence. Arguably the most commonly encountered species of clypeasteroid in South America, I. patagonensis was evidently widespread during the late Oligocene and early Miocene in the southern Patagonian region of Argentina from the southern edge of Golfo San Jorge south to the northern edge of Tierra del Fuego ( Fig. 1 , inset). The recent discovery of specimens from the early Miocene Guadal Formation extends the known range of I. patagonensis westward to the Pampa Castillo region of southern Chile ( Frassinetti & Covacevich, 1999; Andre Wyss, pers. comm. ). Remarks . We recommend usage of the original spelling of the species name used in Desor (1847) and Agassiz & Desor (1847) . Desor (1847) only listed names of taxa from Patagonia, without accompanying figures or descriptions, and these names are therefore here considered nomina nuda . In the same year, Desor (in Agassiz & Desor, 1847 ) provided cursory, but valid descriptions of two taxa, with locality information from the Patagonian region. Lacking figures, these descriptions have been the source of great confusion ever since. The type of one of these forms, Echinarachnius juliensis , from "Port Saint Julien" (Desor in Agassiz & Desor, 1847 : 134), is known to exist in the collections of the Museum of Comparative Zoology, in Cambridge, Massachusetts . All known specimens presently identified as Iheringiella patagonensis compare favorably with this type . The types of the second form, Scutella patagonensis , reported to be from "Port Desire" (Desor in Agassiz & Desor, 1847 : 135), have not been yet been found. The situation is made more difficult by our inability to locate the original material upon which Lahille (1898) based his revision. Given the complex taxonomic history of the species involved, along with the provenance of the material, a full revision of the nomenclature is warranted and pending. For comparison with other taxa described herein, we provide a map of plate architecture of the oral surface of a typical specimen from the Puerto Santa Cruz region of Argentina . This specimen compares most favorably with the type of Scutella juliensis . However, as is common for all such material, it is identified as Iheringiella patagonensis until the situation concerning the relationship between the types of S. juliensis and I. patagonensis can be resolved. What seems clear from the present evidence is that these two named entities are congeneric. Iheringiella does not have any indication of a posterior notch, making it the only described species of South American scutelliform to lack this feature.