Antitropicality and convergent evolution: a case study of Permian neospiriferine brachiopods

Abstract

Antitropical distribution is a biogeographical pattern characterized by natural occurrences of the same species or members of the same clade in the middle-or middle-to-high-latitudinal habitats of both hemispheres, either on land or in marine environments, without appearing in the intervening tropical environments. For most of the noted examples of Permian antitropical distribution, particularly in marine invertebrates, the causes of disjunctions have been mainly linked to either dispersal or vicariance models. Little attention has been paid to other possible mechanisms. This study investigated the antitropicality of some Permian neospiriferine brachiopods through detailed taxonomic revision, comparison of palaeobiogeographical distribution, and a phylogenetic analysis. Several species, previously assigned to Kaninospirifer, are here reassigned to other genera, especially to Fasciculatia in the northern hemisphere and to Quadrospira in the southern hemisphere during the Permian. Both Kaninospirifer and Fasciculatia appear to have been restricted to north-western Pangea and north-eastern Asia during the Permian, but

A three‐dimensional geometric morphometric study of the development of sulcus versus shell outline in Permian neospiriferine brachiopods

“…This seems to support the phylogenetic closeness between these two species already recognized by Lee et al . (), who explained as an anagenetic relationship.…”

“…All these species are placed within the Subfamily Neospiriferinae Waterhouse, , and the similarity of their shell morphologies was discussed by Lee et al . (). In total, 51 individual specimens of these five species were prepared for landmark‐based geometric morphometrics (Table ).…”

“…; also see Lee et al . , figs 9, 10, 12, 13). Interestingly, all these three types of sulcal tongue have been evidently noted in a single species, F. striatoparadoxa , regardless of the rock matrix in which they were preserved, suggesting that there is no definitive correlation between substrate type and sulcal development.…”

“…We here focus on the morphological variation of sulcal development in Fasciculatia Waterhouse, , a common Permian neospiriferine genus in the Arctic region (see Lee et al . ). Three species of this genus, including Fasciculatia striatoparadoxa (Toula, ), F. angulata (Waterhouse, ) and F. groenwalli (Dunbar, ), demonstrate significant variation in the development of sulci.…”

Phylogenetic and ecomorphologic diversifications of spiriferinid brachiopods after the end-Permian extinction

“…However, in the traditional classification of brachiopods, internal characters are always regarded as being diagnostic of a high-level classification unit (Carter and Johnson 2006). This is because the external morphology of the brachiopod shell is hypothesized to have resulted from adaptation to similar environments (Cooper 1972; Lee et al 2016), and internal structures are relatively stable and should be accentuated. From this perspective, internal characters could be given higher weights.…”