Hyainailouridae

Hyainailouridae Temporal range: middle Eocene to middle Miocene
Comparison of various Early to Middle Miocene hyaenodonts, including the hyainailurids Hyainailouros sulzeri (top) and Megistotherium osteothlastes (center), and teratodontid Dissopsalis pyroclasticus
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Class:	Mammalia
Order:	†Hyaenodonta
Superfamily:	†Hyainailouroidea
Family:	†Hyainailouridae Pilgrim, 1932
Type genus
†Hyainailouros (polyphyletic genus) Biedermann, 1863
Subfamilies
†Apterodontinae †Hyainailourinae (paraphyletic subfamily)
Synonyms
Hyaenaelurinae (Pilgrim, 1932) Pterodontidae (Polly, 1996) Pterodontinae (Polly, 1996)

Hyainailouridae ("hyena cats") is a paraphyletic family of extinct predatory mammals from extinct paraphyletic superfamily Hyainailouroidea within extinct order Hyaenodonta. Hyaenodontids arose during the middle Eocene and persisted well into the middle Miocene. Fossils of this group have been found in Asia, Africa, North America and Europe.

General characteristics

Hyainailourids are characterized by long skulls, slender jaws, slim bodies, and a plantigrade stance. They generally ranged in size from 30 to 140 cm at the shoulder. While some measured as much as 1.4 m high at the shoulder with head-body length up to 3.2 m and weighed up to 1,500 kg, most were in the 5–15 kg range, equivalent to a mid-sized dog. The anatomy of their skulls show that they had a particularly acute sense of smell, while their teeth were adapted for shearing, rather than crushing.

At least one hyainailourid lineage, Apterodontinae, was specialised for aquatic, otter-like habits.

Range

They were important hypercarnivores in Eurasia and Africa during the Oligocene, but gradually declined, with almost the entire family becoming extinct by the close of the Oligocene. Only Megistotherium and several of its sister genera, including Hyainailouros and Sivapterodon, survived into the Miocene. Traditionally this has been attributed to competition with carnivorans, but no formal examination of the correlation between the decline of hyaenodontids and the expansion of carnivorans has been recorded, and the latter may simply have moved into vacant niches after the extinction of hyaenodontid species.

Classification and phylogeny

Relations

Hyainailouridae used to be considered a subfamily of Hyaenodontidae, but cladistic study by Sole et al., (2013, 2015) treats it as a distinct family. Two subfamilies are recognized, Apterodontinae and paraphyletic Hyainailourinae.

Taxonomy

• Family: †Hyainailouridae ^{(paraphyletic family)} (Pilgrim, 1932)
  • Subfamily: †Apterodontinae (Szalay, 1967)
    • Genus: †Apterodon (Fischer, 1880)
      • †Apterodon altidens (Schlosser, 1910)
      • †Apterodon gaudryi (Fischer, 1880)
      • †Apterodon langebadreae (Grohé, 2012)
      • †Apterodon macrognathus (Andrews, 1904)
      • †Apterodon rauenbergensis (Frey, 2010)
      • †Apterodon saghensis (Simons & Gingerich, 1976)
      • †Apterodon sp. [Dur At-Talah escarpment, Libya] (Grohé, 2012)
    • Genus: †Quasiapterodon (Lavrov, 1999)
      • †Quasiapterodon minutus (Schlosser, 1910)
  • Subfamily: †Hyainailourinae ^{(paraphyletic subfamily)} (Pilgrim, 1932)
    • Genus: †Megistotherium (Savage, 1973)
      • †Megistotherium osteothlastes (Savage, 1973)
    • Genus: †Mlanyama (Rasmussen & Gutierrez, 2009)
      • †Mlanyama sugu (Rasmussen & Gutierrez, 2009)
    • Genus: †Orienspterodon (Egi, 2007)
      • †Orienspterodon dahkoensis (Chow, 1975)
    • Genus: †Pakakali (Borths & Stevens, 2017)
      • †Pakakali rukwaensis (Borths & Stevens, 2017)
    • Genus: †Simbakubwa (Borths & Stevens, 2019)
      • †Simbakubwa kutokaafrika (Borths & Stevens, 2019)
    • (unranked): †Akhnatenavus clade
      • Genus: †Akhnatenavus (Holroyd, 1999)
        • †Akhnatenavus leptognathus (Osborn, 1909)
        • †Akhnatenavus nefertiticyon (Borths, 2016)
      • Genus: †Hemipsalodon (Cope, 1885)
        • †Hemipsalodon grandis (Cope, 1885)
        • †Hemipsalodon viejaensis (Gustafson, 1986)
      • Genus: †Ischnognathus (Stovall, 1948)
        • †Ischnognathus savagei (Stovall, 1948)
    • Tribe: †Hyainailourini ^{(paraphyletic tribe)} (Ginsburg, 1980)
      • Genus: †Exiguodon (Morales & Pickford, 2017)
        • †Exiguodon pilgrimi (Savage, 1965)
      • Genus: †Falcatodon (Morales & Pickford, 2017)
        • †Falcatodon schlosseri (Holroyd, 1999)
      • Genus: †Hyainailouros ^{(polyphyletic genus)} (Biedermann, 1863)
        • †Hyainailouros bugtiensis (Pilgrim, 1912)
        • †Hyainailouros napakensis (Ginsburg, 1980)
        • †Hyainailouros sulzeri (Biedermann, 1863)
      • Genus: †Parapterodon (Lange-Badré, 1979)
        • †Parapterodon lostangensis (Lange-Badré, 1979)
      • Genus: †Sectisodon (Morales & Pickford, 2017)
        • †Sectisodon markgrafi (Holroyd, 1999)
        • †Sectisodon occultus (Morales & Pickford, 2017)
      • Genus: †Sivapterodon (Ginsburg, 1980)
        • †Sivapterodon lahirii (Pilgrim, 1932)
      • Subtribe: †Isohyaenodontina ^{(polyphyletic subtribe)} (Lavrov, 1999)
        • Genus: †Isohyaenodon ^{(polyphyletic genus)} (Savage, 1965)
          • †Isohyaenodon andrewsi (Savage, 1965)
          • †Isohyaenodon zadoki (Savage, 1965)
      • (unranked): †Pterodon clade
        • Genus: †Kerberos (Solé, 2015)
          • †Kerberos langebadreae (Solé, 2015)
        • Subtribe: †Pterodontina (Lavrov, 1999)
          • Genus: †Pterodon (Blainville, 1839)
            • †Pterodon dasyuroides (Blainville, 1839)
        • Incertae sedis:
          • †"Pterodon" syrtos (Holroyd, 1999)
      • Incertae sedis:
        • †"Pterodon" africanus (Andrews, 1903)
        • †"Pterodon" phiomensis (Osborn, 1909)
        • †"Pterodon" sp. [DPC 5036] (Holroyd, 1999)
    • Tribe: †Leakitheriini (Lavrov, 1999)
      • Genus: †Leakitherium (Savage, 1965)
        • †Leakitherium hiwegi (Savage, 1965)
    • Tribe: †Metapterodontini (Morales & Pickford, 2017)
      • Genus: †Metapterodon (Stromer, 1926)
        • †Metapterodon brachycephalus (Osborn, 1909)
        • †Metapterodon kaiseri (Stromer, 1926)
        • †Metapterodon stromeri (Morales, 1998)
    • Tribe: †Paroxyaenini (Lavrov, 2007)
      • Genus: †Paroxyaena (Martin, 1906)
        • †Paroxyaena galliae (Filhol, 1881)
        • †Paroxyaena pavlovi (Lavrov, 2007)
    • Incertae sedis:
      • †"Pterodon" sp. [BC 15’08] (Pickford, 2008)
      • †Hyainailourinae sp. [GSN AD 100’96] (Morales, 1998)
      • †Hyainailourinae sp. [UON 84-359] (Solé, 2016)
      • †Hyainailourinae sp. A [DPC 6555] (Holroyd, 1999)
      • †Hyainailourinae sp. C [DPC 9243 & DPC 10315] (Holroyd, 1999)
      • †Hyainailourinae sp. D [DPC 6545] (Holroyd, 1999)

Phylogeny

The phylogenetic relationships of family Hyainailouridae are shown in the following cladograms:

†Hyaenodonta	†Eoproviverra †Boualitomus †Hyaenodonta sp. (Quarry L-41, Fayum, Egypt) †Lahimia †Arfiidae †Limnocyonidae †Sinopidae †Hyaenodontoidea †Gazinocyon †Pyrocyon †Galecyon  †Afro‑Arabian clade  †Indohyaenodontidae †Glibzegdouia †Parvavorodon †Koholiidae †Tritemnodon †Furodon †Kyawdawia †Paratritemnodon †Teratodontidae †Hyainailouroidea  †Apterodontinae   †Apterodon  †Apterodon altidens †Apterodon gaudryi  ?  †Apterodon rauenbergensis †Apterodon langebadreae †Apterodon macrognathus  ?  †Apterodon sp. (Dur At-Talah escarpment, Libya) †Apterodon saghensis  †Quasiapterodon  †Quasiapterodon minutus  †Orienspterodon  †Orienspterodon dahkoensis †Hyainailourinae  †Hemipsalodon  †Hemipsalodon grandis †Hemipsalodon viejaensis  †Ischnognathus  †Ischnognathus savagei  ?  †Akhnatenavus clade  †Akhnatenavus  †Akhnatenavus leptognathus †Akhnatenavus nefertiticyon  †Paroxyaenini   †Paroxyaena  †Paroxyaena galliae †Paroxyaena pavlovi †"Pterodon" sp. (BC 15’08) †Hyainailourinae sp. (UON 84-359) †Hyainailourinae sp. C (DPC 9243 & DPC 10315) †Hyainailourinae sp. D (DPC 6545) †Hyainailourinae sp. A (DPC 6555) †"Pterodon" africanus  †Parapterodon  †Parapterodon lostangensis †"Pterodon" sp. (DPC 5036) †"Pterodon" phiomensis †Hyainailourini  †Kerberos  †Kerberos langebadreae †"Pterodon" syrtos  †Pterodon clade   †Pterodontina   †Pterodon  †Pterodon dasyuroides  †Sectisodon  †Sectisodon markgrafi †Sectisodon occultus  †Falcatodon  †Falcatodon schlosseri  †Exiguodon  †Exiguodon pilgrimi †Isohyaenodon zadoki †Isohyaenodon  (†Isohyaenodontina) †Isohyaenodon andrewsi  †Sivapterodon  †Sivapterodon lahirii †Hyainailouros bugtiensis †Hyainailouros napakensis †Hyainailouros †Hyainailouros sulzeri †Hyainailourinae sp. (GSN AD 100’96)  †Simbakubwa  †Simbakubwa kutokaafrika  †Leakitheriini   †Leakitherium  †Leakitherium hiwegi  †Megistotherium  †Megistotherium osteothlastes  †Mlanyama  †Mlanyama sugu  †Metapterodontini   †Metapterodon  †Metapterodon kaiseri †Metapterodon stromeri  †Pakakali  †Pakakali rukwaensis †Prionogalidae	†Lahimia clade †Arfia clade †Galecyon clade †Indohyaenodon clade †Tritemnodon clade †Kyawdawia clade †Hyainailouridae