The tangled cases of Deinogalerix (Late Miocene endemic erinaceid of Gargano) and Galericini (Eulipotyphla, Erinaceidae): a cladistic perspective

Abstract

The Late Miocene giant erinaceid Deinogalerix from Scontrone and Gargano (Italy) is associated with many other vertebrates in deposits of a past island, the "Abruzzo-Apulia Platform". At Gargano, Deinogalerix is accompanied by the moderately endemized Galericini Apulogalerix. This first extensive cladistic analysis is aimed at defining the relationships of Deinogalerix with characteristic members of the tribe Galericini. The analysis was performed on a matrix of 30 characters and 19 taxa and identified some smaller clades, nested within three major ones. The latter include: (i) a pentatomy of Galerix species, (ii) a polytomy of "transitional" Galerix-Parasorex species and (iii) a large clade with Parasorex, Schizogalerix and Gargano representatives. Galerix and Parasorex proved to be paraphyletic and Schizogalerix monophyletic. Based on the results of the analysis, Deinogalerix and Apulogalerix have distinct origins, which supports an asynchronous colonization of the island. The line of Deinogalerix possibly stemmed from some eastern species transitional between Galerix and Parasorex around Mammal Neogene (MN) zone 2. Conversely, the line of Apulogalerix originated from a primitive Parasorex ibericus, or a close relative, around MN 9-10. Another important result was detecting an impressive early Miocene (MN 2?) radiation of Galericini. Moreover, Schizogalerix and Parasorex originated from eastern Galericini morphologically transitional between Galerix and Parasorex.

Cladistics and insular evolution, an unfortunate marriage? Another tangle in the Deinogalerix analysis of Borrani et al. (2017)

“…As I noted, the cladistic analysis of Borrani et al. () fits well with the proposed classification of the Galericini. But does it also provide a reasonable approximation of the evolutionary relationships once we take the palaeobiogeography into account?…”

“…So I was delighted to find Borrani et al. () reconstructing a phylogeny that confirmed my classification. They recognized ‘transitional species’ in the Galerix – Parasorex line, which, with the exception of Galerix iliensis , were exactly the species thought to represent the transition of Galerix into Parasorex at the end of the early Miocene.…”

“…In a recent paper, Borrani et al. () combine two of my greatest interests: insular evolution and the history of the Galericini. I revised the latter tribe (Van den Hoek Ostende, ) and have been adding to its history ever since (Van den Hoek Ostende and Doukas, ; De Bruijn et al., ; Prieto et al., , ).…”

“…For Borrani et al. (), the reconstruction of the Galericini record was only a means to the actual goal of the paper, determining the position of the insular galericine Deinogalerix . They traced the ancestry of this insular giant to an unknown species near the Parasorex / Schizogalerix root in the early part of the Miocene (MN 2?).…”

“…Borrani et al. () clearly state that identifying the source area of Deinogalerix is not the purpose of their paper, but biogeography provides a good test for the credibility of inferred evolutionary relationships. Deriving Deinogalerix from an MN 2 ancestor related to the early Parasorex lineage is, given the distribution of the Galericini at the time, questionable at least.…”