Fossil Lagomorpha (Mammalia) of Italy: Systematics and Biochronology

Abstract

[Abstract] Revisions performed in the last 15 years added remarkable novelties to the taxonomy and biochronology of Italian fossil lagomorphs. Several new taxa have been erected basing on new materials and on the revision of old materials. This paper aims to illustrate the state of the art of such researches. The lagomorph diversity in the Italian Neogene and Pleistocene is quite high, accounting 9 ochotonids, 14 leporids, and 3 stem lagomorphs. Among the lagomorph taxa recorded in Italy, quite a high number are insular or continental endemics. The oldest Italian lagomorphs are the insular endemic Paludotona aff. minor, P. etruria and P. minor from the early-middle Turolian of the Tusco-Sardinia palaeobioprovince, and Prolagus apricenicus and P. imperialis from the late Turolian of the Abruzzi-Apulia palaeobioprovince. In the Italian peninsula, lagomorphs are known since the late Turolian (early Messinian). Prolagus appears in pre-evaporitic Messinian (Prolagus sorbinii) and gives rise to species endemic to the Italian peninsula (Prolagus italicus, late Villányian, central Italy; P. savagei/P. aff. sorbinii, early Villányian-early Biharian, NW and central Italy). The presence of Prolagus was probably constant until the early Biharian, age of its latest report in the Italian peninsula. The gap in the Pliocene fossil record is apparent and due to the extreme scarcity of fossil localities bearing continental vertebrates in the Italian Pliocene. The Asian genus Ochotona appeared at least twice in the Middle-Late Pleistocene of NE Italy, in correspondence of cold climatic phases. Prolagus of the latest Miocene-Early Pliocene of Italy represents the stock which originated the Sardinian lineage of Prolagus. The Sardinian species of Prolagus form an endemic insular anagenetic lineage whose oldest element is the earliest Late Pliocene P. aff. figaro, and which persists till historical times. The main turnover in the lineage, i.e. the transition P. figaro-P. sardus, is an event possibly related to the Mid-Pleistocene Transition. Minor morphological and dimensional changes can be detected among the population of both P. figaro and P. sardus, allowing a relative chronological arrangement of the Prolagus-bearing fossil sites. The first Italian leporids appear in the late Turolian. The continental endemic Alilepus meini is limited to the pre-evaporitic Messinian of Tuscany, and Trischizolagus sp., a taxon that still lacks a detailed systematic revision, is known from a couple of evaporitic and post-evaporitic Messinian fossil localities of northern-central Italy. There are no leporids in the Italian fossil record between the earliest Pliocene and the Late Pliocene (early Villányian), i.e. before the oldest Italian record of Hypolagus. This genus is represented by scanty remains pertaining to different species, and is distributed all along the peninsula (H. petenyii, early Villányian, NW Italy; H. brachygnathus, earliest Biharian, NE Italy; the continental endemic H. aff. brachygnathus, early Biharian, SE Italy). In Sicily, Hypolagus is present with an endemic insular species (H. peregrinus, ?late early Biharian). Also Sardinia records an endemic insular leporid, Sardolagus obscurus (Early Pleistocene). Its morphological features underwent significant modifications due to the permanence in an insular environment, preventing for the moment reliable phylogenetic inferences aimed to link it to known European continental genera. Extant lagomorph genera arrive in Italy with some delay with respect to the rest of Europe. In Europe, Oryctolagus is known since the Late Pliocene, whereas the oldest Italian species, O. valdarnensis, is known from the Early Pleistocene (late Villányian-early Biharian) of central and probably SE Italy. After a gap in the late Biharian, Oryctolagus is recorded in the earliest Toringian of NW and western-central Italy with O. burgi. The extant species O. cuniculus appears in the Italian peninsula in the late Middle Pleistocene. Its presence is attested until MIS 3 in several Italian fossil sites, and in the MIS 2 and early Holocene in southernmost Italy, Sicily, and southern Italian minor islands. It can not be excluded that those relict populations interacted with the rabbits introduced by humans during the Holocene. As for Lepus, the oldest reliable Italian report dates back to the late early Biharian of central Italy (originally classified as L. terraerubrae). Extant species of Lepus appear in Italy since the early Toringian. Among them, Lepus corsicanus has the oldest record; this species expands its geographical distribution to Sicily in the latest Pleistocene. Follows L. europaeus, whose oldest reliable Italian record is in the earliest late Toringian; this species expanded in the Italian peninsula at the expenses of L. corsicanus. During the Last Glacial Maximum, L. timidus makes sporadic appearance(s) in Italy, even in southern regions. Though showing endemic characters, the Sardinian hare L. mediterraneus is the result of human introduction in historical times.