https://orcid.org/0000-0002-9567-9401
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Abstract
The family Inversiulidae, and its only genus Inversiula, are unique among cheilostome bryozoans owing to the reverse orientation of the operculum, which hinges distally instead of proximally. Inversiula currently includes four extant and one fossil species almost exclusively distributed in the Southern Hemisphere. A phylogenetic analysis of the Inversiulidae based on morphological characters was performed, showing the existence of two clades with contrasting development of the frontal shield. As a result of this analysis, Parainversiula gen. nov. is erected to contain inversiulid species with an umbonuloid frontal shield structure and fewer than 30 central spoked pores. Two poorly known fossil species from the early Miocene of Patagonia (Argentina), originally assigned to the genus Microporella, are here redescribed as Parainversiula sp. and P. chubutiana (Canu) comb. nov. The historical, time-calibrated biogeography of Inversiulidae was estimated using an event-based, multi-model quantitative analysis. The analyses estimated that Australasia was the ancestral area of Parainversiula and a dispersion of the genus into South America occurred between the late Eocene and Oligocene (c. 23–42 Ma), an event that could have been helped by the origin of the Antarctic Circumpolar Current.
http://zoobank.org/urn:lsid:zoobank.org:pub:A2CFF6CE-9BC4-4D07-AA4A-890CC1F372D3
Acknowledgements
Two anonymous reviewers made useful comments on an earlier version of this article. Thanks to Guido Pastorino (MACN) and Miguel Griffin (Museo de La Plata, UNLP) for collecting material from Monte León. Anahi Azpeitía and Fabián Tricárico operated the Scanning Electron Microscope at LIMF and MACN, respectively. Claudia del Río allowed us access to the MACN-Pi collection. This work benefited from a grant of the French state managed by the Agence Nationale de la Recherche via the programme ‘Investissements d'avenir’ (ANR-11-INBS-0004-RECOLNAT). We thank Jean-Michel Pacaud (MNHN) for information about the Tournouër Collection at the MNHN and Loïc Villier for arranging SEM imaging at Sorbonne Université.
Disclosure statement
No potential conflict of interest was reported by the authors.
Supplemental material
Supplemental material for this article can be accessed here: https://doi.org/10.1080/14772019.2023.2279674.
Associate Editor: Tim Ewin