Manta-like planktivorous sharks in Late Cretaceous oceans

Abstract

The ecomorphological diversity of extinct elasmobranchs is incompletely known. Here, we describe Aquilolamna milarcae, a bizarre probable planktivorous shark from early Late Cretaceous open marine deposits in Mexico. Aquilolamna, tentatively assigned to Lamniformes, is characterized by hypertrophied, slender pectoral fins. This previously unknown body plan represents an unexpected evolutionary experimentation with underwater flight among sharks, more than 30 million years before the rise of manta and devil rays (Mobulidae), and shows that winglike pectoral fins have evolved independently in two distantly related clades of filter-feeding elasmobranchs. This newly described group of highly specialized long-winged sharks (Aquilolamnidae) displays an aquilopelagic-like ecomorphotype and may have occupied, in late Mesozoic seas, the ecological niche filled by mobulids and other batoids after the Cretaceous–Paleogene boundary.

A new cuspidate ptychodontid shark (Chondrichthyes; Elasmobranchii), from the Upper Cretaceous of Morocco with comments on tooth functionalities and replacement patterns

“…Small teeth with conical, pointed cusps belonging to the genus Cretomanta have been also found in the lower Turonian of Akrabou Formation (Goulmima region). Cretomanta was most probably a planktivorous elasmobranch putatively assigned to the family Aquilolamnidae (see Case et al, 1990; Villalobos-Segura et al, 2019 ; Vullo et al, 2021 ).…”

Digging deeper into colonial palaeontological practices in modern day Mexico and Brazil

“…As mentioned above, fossils registered in a private collection in Mexico cannot be transferred to other collections [46], hence, this specimen will remain under the custody of the private collector even if it is loaned to a museum. A correction to the Supplementary Materials was published by Vullo et al on 8 April 2021 [76] and an erratum only one week later [77]. The erratum states that the fossil will be housed at Museo del Desierto in Saltillo, Coahuila, until the new museum opens.…”

“…The erratum states that the fossil will be housed at Museo del Desierto in Saltillo, Coahuila, until the new museum opens. In both amended versions of the supplement [76,77], Vullo et al restated the registration number incorrectly as INAH 2544 P.F.17 (sic), and did not mention that this is a private collection [71], nor that the fossil was purchased, as originally stated by the authors. Moreover, the owner of the A. milarcae specimen recently declared that he bought the rock that contains the fossil [73].…”

Publication pressure threatens the integrity of palaeontological research

“…More recently, a Brazilian dinosaur specimen named "Ubirajara jubatus", which was described in a publication in Cretaceous Research on 13 December 2020 came under scrutiny for similar reasons, and was temporarily retracted (and remains retracted at the time of writing) while an investigation is underway (54). Another controversial specimen, this time a ray-like shark specimen from Mexico named Aquilolamna milarcae, was published in Science in March 2021 (55). This fossil sparked controversies because it had been purchased and, at the time of its publication, was being housed in a private collection (until a new museum is built).…”

“…Both the purchase of fossil material and housing fossils in private collections are prohibited under Mexican fossil laws (30,56). After the initial publication, the authors resolved both issues, firstly by moving the specimen to a museum where it will apparently be accessible to other researchers (again, until the new museum is ready) (57) and secondly, by removing information about the specimen having been purchased to the supplementary materials (58), likely in an attempt to disguise this violation (30).…”