A new form of wapiti Cervus canadensis Erxleben, 1777 (Cervidae, Mammalia) from the Late Pleistocene of France

Abstract

A well-preserved antlered braincase of wapiti (Cervus canadensis) from the Late Pleistocene of Saint-Hippolyte (Puy de Dôme, France) is described herein. The specific morphology of antlers suggests peculiar adaptations to the open landscapes of periglacial tundra-steppe that permitted to identify a new fossil subspecies Cervus canadensis combrayicus n. ssp. The specimen attests the occurrence of Cervus canadensis in the paleontological record of Western Europe and helps to clarify the systematical position of some disputed findings of Cervus from Western Europe. The revised systematic position of some fossil and sub-fossil cervid findings reveals the paleobiogeographic story of wapiti in Western Europe during the Last Glacial Maximum and the postglacial time. The treeless Alpine altitudes and Sweden are proposed as the glacial refugia for the last European wapiti. The medium-sized deer from Capri Island is regarded as an insular dwarfed wapiti C. canadensis tyrrhenicus closely related to the continental form C. canadensis palmidactyloceros from the alpine refugium.

Introduction

The occurrence of another “elaphine” deer species close to modern Cervus canadensis in the paleontological record of Europe was a subject of long-lasting debates since Owen (1846) and then Pomel (1853) reported fossil remains of a large deer similar to American wapiti. The reports of wapiti from Paleolithic sites of Western Europe were quite frequent over the next decades (Gervais, 1861, Gervais, 1872, Rivière, 1873, Rivière, 1905, Belgrand, 1883, De Rance, 1888, Martin, 1893).

Nonetheless, a conservative and more cautious approach to the systematics of the “elaphine” deer (the species complex of Cervus elaphus and Cervus canadensis) dominated in the zoological literature of the second half of 20th century, where American wapiti and Asian maral and izubr stags were considered as subspecies of common red deer Cervus elaphus (Heptner and Zalkin, 1947, Ellerman and Morrison-Scott, 1951, Flerov, 1952, Sokolov, 1959, Geist, 1998). It is still possible to find this type of approach in some recent publications, which regard the subspecies of red deer and wapiti as informal groups “elaphoids” and “wapitoids” (Meiri et al., 2018). The caution apparently was produced by lack of detailed morphological, biological, and ethological studies, while the body size — the only readily available feature distinguishing red deer and wapiti — varies greatly within the better known C. elaphus (Heptner and Zalkin, 1947, Flerov, 1952, Geist, 1998). The Middle Pleistocene red deer subspecies C. elaphus acoronatus that has similar body size to modern wapiti is a good example of the challenge faced by researchers. Therefore, the exceptionally large remains of Cervus from the Late Pleistocene of Europe have often been regarded as an intraspecific variation of red deer (Azzaroli, 1961, Lister, 1987a). Although the presence of two distinct size forms of the “elaphine” deer in the Late Pleistocene of Western Europe has been recognized (Prat and Suire, 1971, Lister, 1987a, Guadelli, 1997), the adequate taxonomical interpretation based on this size difference was not possible due to lack of complete antlers preserving distal portions that provide the main diagnostic characters of “elaphine” deer species and subspecies (Lydekker, 1896, Heptner and Zalkin, 1947, Flerov, 1952, Geist, 1998). Therefore, the question on the occurrence of wapiti in the Late Pleistocene of Europe remained open for more than a century.

The new arguments for the reassessment of systematical criteria for “elaphine” deer were obtained much later when genetic studies revealed an important phylogenetic distance between European red deer and Asian and American wapitis (Kuwayama and Ozawa, 2000, Polziehn and Strobeck, 2002, Ludt et al., 2004, Pitra et al., 2004). The molecular data permitted to reinstate the species status for Cervus canadensis (Polziehn and Strobeck, 2002), further supported by biological, ecological and ethological data (Schonewald, 1994, Croitor and Obada, 2018).

Recently, paleogenetic (Stankovic et al., 2011, Meiri et al., 2018) and paleontological (Croitor and Obada, 2018) evidence confirmed the presence of a wapiti closely related to the modern Siberian form of C. canadensis sibirica/songarica (the subspecies name spelling sibirica and songarica is according to the original publication of Severtzoff, 1873, Severtzoff, 1876) in the Late Pleistocene of Eastern Europe. Stankovic et al. (2011) regard the arrival of wapiti in Crimea as a part of the invasion of cold-loving forms into Eastern Europe at the end of the Würm II/Würm III Interstadial period.

Nonetheless, despite the numerous old reports of the occurrence of wapiti in the Late Pleistocene of Western Europe, a doubtless demonstration of this “cryptic” mammal dispersal event is still missing (Meiri et al., 2018).

Fossil remains of wapiti from the Late Quaternary of Western Europe were reported under several species and arbitrary names. Owen (1846) described the proximal part of an exceptionally large shed antler with two basal tines (brow and bez) from Kent’s Cavern as a new species Cervus (Strongyloceros) spelaeus and suggested close relationships of this specimen with modern wapiti Cervus canadensis Erxleben, 1777. Later, Pomel (1853) reported as Cervus intermedius de Serres, 1838 some remains of a large deer similar to the American wapiti from several fossiliferous sites of Auvergne (Central France). The species name used by Pomel (1853) is not appropriate. Cervus intermedius was mentioned for the first time by de Serres (1838) in the fossil fauna list of the Middle Pleistocene site of the Lunel-Viel Cave and reasonably was regarded by Boule (1892) as a junior synonym of C. elaphus. Pomel (1853) provided some diagnostic characters distinguishing the European wapiti from the common red deer: the rugosity of dental enamel, the comparatively larger size of antlers, and the poor development of antler crown as in modern American wapiti. Pomel (1853) indicated several Auvergnian sites where Cervus intermedius was found (Tour-de-Boulade, Champeix, caverne de Châtelperron, St-Privat-d’Allier), however, Lunel-Viel was not mentioned among the sites where this species was recorded.

Gervais, 1861, Gervais, 1872 reported a large-sized Cervus strongyloceros from the Cave of Pontil near Saint-Pons (Herault, Southern France) and Loubeau Grotto near Mille (Western France), associated with a typical Late Pleistocene fauna. Cervus canadensis was reported by Rivière, 1873, Rivière, 1905 from the Paleolithic faunas of Caverne du Cavillon near Menthon and La Muthe Grotto in Dordogne (France). Gaudry (1876) ascribed to Cervus canadensis some cervid remains from Louverné: a basal fragment of very large shed antler with brow and bez tines and an isolated large molar with strong entostyle. The same author (Gaudry, 1880) reported the findings of wapiti from Laugerie-Basse (Dordogne) in association with abundant remains of a horse, as well as with remains of reindeer and saiga. Martin (1893) described a basal fragment of antler of Cervus canadensis from the Bassin du Pignon (Hautes-Alpes) and gave some measurements of this specimen: the distance between the brow and bez tines is 23 mm, the maximal diameter of the beam between the bez and brow tines is 55 mm, the minimum diameter of the same part of beam is 40 mm. Belgrand (1883) described a proximal part of antler with pedicle from Genelle in the Seine valley as Cervus (canadensis) (sic) noticing the exceptionally large size of the antler (the circumference of the pedicle is 200 mm; the antler beam circumference above the bez tine is 210 mm).

The discussion on the occurrence of the large-sized elaphine deer in France was reopened by Friant, 1952, Friant, 1957 who regarded the giant cave stag from Kent’s Hole as an extremely specialized elaphine deer Strongyloceros spelaeus Owen, 1846. Friant (1957) proposed to give Owen’s Strongyloceros the full genus rank, but this suggestion was not supported (Lister, 1987a).

Prat and Suire (1971) noticed an important and statistically meaningful difference in the dentition and third phalanx sizes recorded in the samples of the elaphine deer collected from different layers of the Paleolithic site Combe-Grenal (Dordogne). Those layers correspond to Würm I and Würm II and have yielded different mammalian faunas that indicate alternating cold and warm climate conditions. The smaller elaphine form that comes from the “Würm I” phase is associated with typically forest fauna, while the large elaphine deer from the “Würm II” stage comes from the deposits characterized by more severe climate conditions. According to Prat and Suire (1971), this size difference may have a taxonomical significance at the subspecies level.

Raynal et al. (1984) confirmed that the Late Pleistocene paleontological record of southwestern France has yielded the remains of two forms of “elaphine” deer distinguished by body size. According to Raynal et al. (1984), the relatively small red deer existed during the phase Wurm I and then was replaced by a larger elaphine deer form (“grand Elaphe”) at the beginning of phase Wurm II. The antlered cervid braincase from Saint-Hippolyte belongs, according to Raynal et al. (1984), to the large “elaphine” form associated with “cold” fauna. Raynal et al. (1984) noticed the poor development of the distal antler crown in the deer from Saint-Hippolyte that differs from the multiaxial crown typical of the modern European red deer, therefore this specimen was arbitrarily described as C. elaphus acoronatus. According to Guadelli (1997), the “larger elaphine” deer from Saint-Hippolyte is similar to the large cervid form C. elaphus ssp. from Combe-Grenale.

Guadelli (1997) reported some distinctions in dental morphology between “large elaphine” and “small elaphine” forms from Combe-Grenale, such as the relatively linguolabially broader upper molars and very frequent lingual groove in P² in the “large elaphine” deer. Those morphological differences are important since they indicate a stronger brachyodonty (a primitive morphological character) and a more advanced degree of molarization of P² (an advanced morphological character) in the “larger elaphine” deer. Guadelli (1997) also indicated a stronger development of entostyle and a stronger developed lingual cingulum in molars of the “larger elaphine” deer, as well as a paraconid more frequently separated from parastylid in P₂, a more frequent and higher degree of molarization of P₄ (the metaconid and paraconid are connected and close the second dental valley) that distinguish the “large elaphine” deer from the “smaller” one. Guadelli (1997) estimated the differences in dental morphology as taxonomically significant and proposed the species name Cervus simpicidens for the “smaller elaphine” deer from Combe-Grenale.

However, the species name Cervus simplicidens is already preoccupied by Lydekker (1876). This is a case of primary homonymy that makes C. simplicidens Guadelli, 1997 permanently invalid (ICZN: Article 52.2). Besides that, the selected — or, better to say, available — diagnostic morphological characters Guadelli’s species possesses do not allow to distinguish it from other forms of red deer. The primitive stage of molarization of P₄ indicated by Guadelli (1997) is quite variable in C. elaphus and is recorded in varying frequencies in different red deer samples. According to Janis and Lister (1985), the simple unmolarized P₄ is found in 8% of specimens of C. elaphus from the Middle Pleistocene of Mosbach (Germany) and in 47% of specimens of red deer from the early Holocene of England. A rather high frequency of unmolarized P₄ is also recorded in the sample of indigenous Early Iron Age Crimean red deer (Croitor, 2016a).

The species status itself of the smaller elaphine deer from Combe-Grenale was a matter of doubts. Armand (1998), who reported the findings of Guadelli’s ‘C. simplicidens’ together with larger Cervus elaphus from the Mousterian site of Bourgeois-Delaunay, noticed that the morphology of P₄ in the smaller deer form may be variable and occasionally shows a molarized condition. Steele (2004) noticed that the arguments for the creation of a new species ‘C. simplicidens’ are not sufficient, while Monchot (2008) supposed that the small body size of this cervid form may be explained by the clinal body size variation of C. elaphus. Becker et al. (2009) regarded ‘C. simplicidens’ as a subspecies of C. elaphus.

Thus, the question on the taxonomical status and systematical position of the “large elaphine” deer from the Late Pleistocene of France remains unresolved. The present work proposes a new look at the cervid antlered braincase from the Late Pleistocene of Saint-Hippolyte (France) and other puzzling findings of elaphine deer from Europe. Special attention is paid to the morphological peculiarities of antlers of the deer from Saint-Hippolyte that reveal specific ecomorphological adaptations and thus provide arguments that permit the establishment of a new subspecies for the Late Pleistocene wapiti of Western Europe.