Belongs within: Creodonta.
The Proviverrinae are a generalised group of creodonts that are probably paraphyletic with regard to other more derived hyaenodontids. Two distinct groups have been identified within the proviverrines that may represent distinct lineages: one, including the relatives of Proviverra, is characterised by molars with a tricuspid talonid bearing a broad postfossid, and a two-rooted P/1, whereas the other, including the relatives of Prototomus has molars with a reduced entoconid and elongated postfossid, and a primitively single-rooted P/1 (Gheerbrant et al. 2006).
Predators of the European Eocene
Published 16 July 2020
Among mammals in today’s modern fauna, the role of terrestrial carnivore is dominated by members of one particular lineage, known (appropriately enough) as the Carnivora. But travel back in time to the Eocene period, roughly 56 to 34 million years ago, and you’ll find a range of now extinct groups sharing that role. This post is looking at one of those groups, the proviverrines.
The Proviverrinae are a subgroup of the Hyaenodontidae, one of the two families of carnivores commonly associated as the creodonts. I’ve discussed creodonts before, and the overhanging question of whether they form a coherent evolutionary group. Currently, my impression is that most mammal palaeontologists seem inclined to think that hyaenodontids and oxyaenids probably do not share an immediate common ancestry. However, nor is there any clear idea of what else either group may relate to.
Historically, proviverrines have been treated as the basal grade from which other groups of hyaenodontids were derived with representatives known from Europe and North America. However, a phylogenetic analysis of early hyaenodontids by Solé (2013) lead to a division of the ‘proviverrines’ between three monophyletic subfamilies: the Proviverrinae proper, the Sinopinae and the Arfiinae. Under this system, the Proviverrinae are a uniquely European group. As is standard in mammalian palaeontology, proviverrines (in the strict sense) are distinguished from other hyaenodontids by features of the teeth. Notable among these is the presence of a double root on the first lower premolar of most proviverrines; other hyaenodontids have a single root on this tooth.
The earliest proviverrines are known from the very beginning of the Eocene (Solé et al. 2014). Current thinking is that their ancestors probably immigrated into Europe around this time from Africa. The Late Paleocene Tinerhodon disputatum from northern Africa resembles a proviverrine in overall appearance but was probably more basally placed in respect to hyaenodontids as a whole. The name ‘Proviverra‘ can be read as ‘early civet’ and while proviverrines were not related to modern civets (which are, of course, true carnivorans) this is probably not a bad indication of the overall appearance of their original appearance. These were very small animals, probably less than 100 g in body weight, and probably had a fairly generalised diet of small vertebrates and invertebrates. At first, proviverrines seem to have been restricted to southern Europe, what is now Spain and the very southernmost part of France. Northern Europe was inhabited by the Arfiinae and Sinopinae, as well as species of Oxyaenidae (the other ‘creodont’ family). Sinopinae were also found in southern Europe and may have excluded the proviverrines from evolving larger size. However, the other hyaenodontids and oxyaenids went extinct in Europe not to long after the beginning of the Eocene. A turnover in the mammalian fauna of North America around this time appears to be due to a cooling of the climate; though the evidence for climate cooling is less clear in Europe, it seems reasonable that it was going through similar changes. With their competitors out of the picture, the proviverrines rapidly diversified into the regions and niches that had been left unoccupied.
The largest proviverrines, members of the genera Prodissopsalis, Paenoxyaenoides and Matthodon, would eventually reach weights of close to twenty kilograms, about as large as a medium-sized dog. They would also diversify in their habits. Members of the genera Oxyaenoides and Paenoxyaenoides were cursorial hypercarnivores, their dentition specialised for a diet almost exclusively of meat*, like that of a modern cat. Matthodon and Quercytherium, in contrast, were genera whose dentition showed more adaptations for cracking hard materials such as bone. They may have had lifestyles more like those of hyaenas, with Matthodon (which combined adaptations for hypercarnivory and bone-cracking) perhaps being more of an active hunter than Quercytherium.
*These two genera also provide an excellent example of the role of convergent evolution in the evolution of mammalian carnivores. Their appearance to other hypercarnivorous hyaenodontids was such that it was only recently that they were recognised as proviverrines rather than members of other subfamilies no longer thought to have been found in Europe. And not only are they remarkably convergent on other subfamilies, the phylogenetic analysis of proviverrines by Solé et al. (2014) suggests that they’re not even directly related to each other within that clade.
Proviverrines remained the dominant mammalian carnivores in Europe for about the next twenty million years but then went into a sharp decline. This reversal of fortunes may have been due to the increasingly cool, dry conditions developing at this time, and/or it may have been related to competition from the first true carnivorans arriving in Europe. The larger, more specialised proviverrines disappeared rapidly when their time came. The last surviving genus, Allopterodon, was a small form, little more than one kilogram in weight, and had a generalised dentition indicating a relatively unspecialised diet. This may have been a return to something like the lineage’s original form but it would not save it: by the end of the Eocene, the proviverrines would be completely extinct.
Systematics of Proviverrinae
Characters (from Gunnell 1998): M1-3 tritubercular; m1-3 tuberculo-sectorial; m1-3 usually with distinct metaconids and moderate shearing specialisations; premolars elongate, often laterally compressed; feet and limbs may be specialised for climbing or cursoriality.
<==Proviverrinae [Proviverridae, Proviverrini, Stypolophinae] | i. s.: ‘Didelphis’ colchesteri Owen 1846V65 |--Masrasector aegypticum Simon & Gingerich 1974S78 |--Tinerhodon disputatum Gheerbrant 1995GI06 |--Galecyon Gingerich & Deutsch 1987GI06, SM93 |--GazinocyonGI06 |--ProviverroidesGI06 |--Pyrocyon dioctetusGI06, HUG17 |--Paratritemnodon Rao 1973GI06, SM93 |--Anasinopa Savage 1965S78, V67 | `--A. leakeyiS78 [=Paracynohyaenodon leakeyiV67] |--Acarictis Gingerich & Deutsch 1987GI06, SM93 | `--A. ryani Gingerich & Deutsch 1989GI06 |--Parvagula Lange-Badre 1987GI06, SM93 | `--P. palulae Godinot et al. 1987GI06 |--Boualitomus Gheerbrant, Iarochene et al. 2006GI06 | `--*B. marocanensis Gheerbrant, Iarochene et al. 2006GI06 |--Arfia Van Valen 1965GI06, V67 | |--*A. opisthotoma (Matthew 1901) [=Sinopa opisthotoma]V65 | `--A. shoshoniensis (Matthew 1915) [=Sinopa shoshoniensis]V65 |--Propterodon Martin 1906S78, V66 | |--P. morrisi (Matthew & Granger 1924) [=Paracynohyaenodon morrisi; incl. *Pr. irdinensis Matthew & Granger 1925]V65 | `--P. minutus (Douglass 1901)V65 [=Hyaenodon minutusV66] |--Prototomus Cope 1874GI06, V66 [incl. Protoproviverra Lemoine 1891V67] | |--*P. viverrinus Cope 1874V66, C77 [=Stypolophus viverrinusC77] | |--P. minimus Smith & Smith 2001GI06 | |--P. mordax (Matthew 1915)V65 | |--P. multicuspis (Cope 1875)V65 [=Stypolophus multicuspisC77] | |--P. palaeonictides (Lemoine 1880)V65 (see below for synonymy) | |--P. secundaria (Cope 1875)V65 [=Sinopa secundariaV66, Stypolophus secundariusC77] | |--P. torvidus Van Valen 1965V65 | `--P. vulpecula (Matthew 1915)V65 `--Proviverra Rütimeyer 1862 (see below for synonymy)V67 |--*P. typica Rütimeyer 1862V65 [incl. *Prorhyzaena egerkingiae Rütimeyer 1891V66, V65] |--‘Triacodon’ aculeatus Cope 1872 [=Stypolophus aculeatus]C77 |--P. eisenmanni Godinot 1981GI06 |--P. gracilis (Matthes 1952) [=Leonhardtina gracilis; incl. Geiselotherium pilzi Matthes 1952]V65 |--P. grangeri (Matthew 1906)V65 [=Sinopa grangeriV66] |--‘Stypolophus’ hians Cope 1877C77 |--P. major (Wortman 1902)V65 [=Sinopa majorV66] |--P. minor (Filhol 1877) [=Cynohyaenodon minor]V65 |--P. ‘minor’ (Wortman 1902) non Cynohyaenodon minor Filhol 1877V65 [=Sinopa minorV66] |--‘Sinopa’ mordaxV66 |--‘Sinopa’ multicuspisG52 |--V. pungens (Cope 1872)V65 [=Sinopa pungensD07] |--P. rapax (Leidy 1871)V65 [=Sinopa rapaxV66] | |--P. r. rapaxV65 | `--P. r. lania (Matthew 1909)V65 |--‘Prototomus’ strenuus Cope 1875C77 [=Sinopa strenuaG52, Stypolophus strenuusC77] `--‘Sinopa’ vulpecula Matthew 1915G52
Prototomus palaeonictides (Lemoine 1880)V65 [=Proviverra palaeonictidesV66, Protoproviverra palaeonictidesV66, Prov. pomeli Lemoine 1891V66]
Proviverra Rütimeyer 1862 [incl. Geiselotherium Matthes 1952 V67, Leonhardtina Matthes 1952 V67, Prorhyzaena Rütimeyer 1891, Sinopa Leidy 1871, Stypolophus Cope 1872]V67
*Type species of generic name indicated
References
[C77] Cope, E. D. 1877. Report upon the extinct Vertebrata obtained in New Mexico by parties of the expedition of 1874. Geographical Surveys West of the One Hundredth Meridian 4 (2): i–iv, 1–370.
[D07] Dixon, D. 2007. The Complete Illustrated Encyclopedia of Dinosaurs & Prehistoric Creatures. Hermes House: London.
[G52] Gazin, C. L. 1952. The Lower Eocene Knight Formation of western Wyoming and its mammalian faunas. Smithsonian Miscellaneous Collections 117 (18): 1–82, 11 pls.
[GI06] Gheerbrant, E., M. Iarochene, M. Amaghzaz & B. Bouya. 2006. Early African hyaenodontid mammals and their bearing on the origin of the Creodonta. Geological Magazine 143 (4): 475–489.
[HUG17] Halliday, T. J. D., P. Upchurch & A. Goswami. 2017. Resolving the relationships of Paleocene placental mammals. Biological Reviews 92 (1): 521–550.
[S78] Savage, R. J. G. 1978. Carnivora. In: (V. J. Maglio, V. J., & H. B. S. Cooke (eds) Evolution of African Mammals pp. 249–267. Harvard University Press: Cambridge (Massachusetts).
Solé, F. 2013. New proviverrine genus from the Early Eocene of Europe and the first phylogeny of Late Palaeocene–Middle Eocene hyaenodontidans (Mammalia). Journal of Systematic Palaeontology 11 (4): 375–398.
Solé, F., J. Falconnet & L. Yves. 2014. New proviverrines (Hyaenodontida) from the early Eocene of Europe; phylogeny and ecological evolution of the Proviverrinae. Zoological Journal of the Linnean Society 171: 878–917.
[SM93] Stucky, R. K., & M. C. McKenna. 1993. Mammalia. In: Benton, M. J. (ed.) The Fossil Record 2 pp. 739–771. Chapman & Hall: London.
[V65] Van Valen, L. 1965. Some European Proviverrini (Mammalia, Deltatheridia). Palaeontology 8 (4): 638–665.
[V66] Van Valen, L. 1966. Deltatheridia, a new order of mammals. Bulletin of the American Museum of Natural History 132 (1): 1–126.
[V67] Van Valen, L. 1967. New Paleocene insectivores and insectivore classification. Bulletin of the American Museum of Natural History 135 (5): 217–284.