Late Miocene Carnivora from Chad: Lutrinae (Mustelidae)

Abstract

We describe extensive Late Miocene fossil Lutrinae from Toros-Menalla, Chad. A minimum of four species are present in this fossiliferous area. Such a large number of species, diverse in size and dental morphology, is significant and unique in the fossil record of the subfamily Lutrinae in the Neogene of Africa. Two new taxa are described, Sivaonyx beyi sp. nov. and Djourabus dabba gen. nov. sp. nov.; the two other species, which are represented by more fragmentary remains, are assigned to Lutrinae indet. aff. Torolutra sp. and Lutrinae indet. aff. Aonyx sp. Sivaonyx beyi is the best known of the species. It is represented by many dental remains and a subcomplete skeleton. Postcranial characters of this species are not particularly specialized. It is interpreted here as a terrestrial predator with poorly developed aquatic adaptations. Fossils of otters are known from ten different localities at Toros-Menalla, each of which yielded a single individual of one or two species. The presence of four morphologically distinct otters in the area is indicative of a palaeoenvironment with a relatively well-developed freshwater system of lakes and/or rivers.

Pliocene Carnivora (Mammalia) from the Hadar Formation at Dikika, Lower Awash Valley, Ethiopia

“…Interestingly, L. palaeindica resembles H. maculicollis more than L. lutra in its relatively weak post-orbital processes and frontals that are about as broad between the orbits as at the post-orbital constriction Torolutra ougandensis was erected by Petter et al (1991) for early Pliocene specimens from Uganda, and several fossils have been assigned to the same genus or species. Those from the Middle Awash (Haile-Selassie, 2008; there is also a mandible collected by the RVRME, NME-KL-225-1) are of similar age, but the specimen from Toros-Menalla in Chad (Peigné et al, 2008) is older, while those from Koobi Fora (Werdelin and Lewis, 2013) are much younger. Of the generic characters, the position of the masseteric fossa is of doubtful value, as in the specimens from Koobi Fora it reaches almost as far mesially as in Lutra; it is likely that the fossa migrates rostrally with the shortening of the mandible.…”

A new otter of giant size,Siamogale melilutrasp. nov. (Lutrinae: Mustelidae: Carnivora), from the latest Miocene Shuitangba site in north-eastern Yunnan, south-western China, and a total-evidence phylogeny of lutrines

“…We used Mesquite (Maddison & Maddison 2015) to generate the morphological matrix of characters (37 craniodental characters) for 11 fossil otter taxa (at the generic or species level) and eight extant species: six extant otter species (Pteronura brasiliensis, Lontra canadensis, Lontra felina, Enhydra lutris, Lutra lutra, Aonyx capensis) plus Martes americana and Galictis cuja. Our coding of fossil bunodont otters depends both on our own observations of the specimens from the Siwaliks and on published sources: Pilgrim (1932), Grohe (2011) for Vishnuonyx; Peigne et al (2008), Grohe et al (2013) for Sivaonyx (S. gandakasensis, S. bathygnathus, S. beyi); Falconer (1868), Matthew (1929), Geraads et al (2011) for Enhydriodon (E. sivalensis, E. falconeri, E. dikkikae). Other fossil taxa included in our cladistic analysis are coded mainly based on illustrations and descriptions from the literature: Roman & Viret (1934), Helbing (1936) for Paralutra jaegeri; Willemsen (1983), Villier et al (2011) for Paralutra garganensis; Ginsburg et al (1983), Villalta & Crusafont-Pairo (1945), H€ urzeler (1987 for Tyrrhenolutra helbingi; Morales & Pickford (2005) for Paludolutra (P. lluecai, P. marammena, P. campanii); Berta & Morgan (1985), Lambert (1997) for Enhydritherium terranovae; Zdansky (1924) for 'Lutra' aonychoides).…”

“…Finally, coding for extant lutrines and Siamogale is mostly based on our own examination of specimens and from Grohe et al (2010) and Grohe (2011). We did not include the African bunodont genus Djourabus (Peigne et al 2008), which is too poorly known to code.…”

New material of Sivaonyx bathygnathus (Lutrinae, Mustelidae) from the early Pliocene of Siwaliks, Pakistan

“…All the described specimens including the type specimen and the specimen under study were collected from the Hasnot area. Similarly on the basis of similarities to the type specimen (GSI D33) of S. bathygnathus from the Siwaliks, other species of this genus have been described from the Miocene-Pleistocene deposits of North America, Europe and Africa (Repenning, 1976;Alcalá, 1994;Hürzeler, 1987;Pilgrim, 1931;Villalta & Crusafont-Pairó, 1945;Willemsen, 1992Willemsen, , 1999Hendey, 1974;Morales et al, 2005;Morales & Pickford, 2005a,b;Pickford, 2007;Petter et al, 1991;Stromer, 1931;Werdelin, 2003;Bonis et al, 2008;Peigné et al, 2008;Grohé et al, 2013).…”

“…Lower dental measurements (in mm) of different Sivaonyx species. Measurements are taken from Pilgrim (1932), Colbert (1935) Qi (1983), Zong (1997), Werdelin (2003), Morales et al (2005), Morales & Pickford (2005a,b), Pickford (2007), Peigné et al (2008), Grohé et al (2013 Other species. Sivaonyx africanus (Stromer, 1931), Sivaonyx hendeyi (Morales et al, 2005), Sivaonyx ekecaman (Werdelin, 2003), Sivaonyx kamuhangirei (Morales & Pickford, 2005a), Sivaonyx hessicus (Lydekker, 1890), Sivaonyx beyi , Sivaonyx gandakasensis (Pickford, 2007) Sivaonyx soriae (Morales & Pickford, 2005b), Sivaonyx senutae (Morales & Pickford, 2005b Diagnosis.…”