Dissacus: now a Palaeocene ‘devil’ in the LRT

According to Wikipedia,
“Dissacus (Fig 1) is a genus of extinct carnivorous jackal to coyote-sized mammals within the family Mesonychidae, an early group of hoofed mammals that evolved into hunters and omnivores.”

This taxon has bounced around the LRT due to its primitive, generalized morphology.

As of today (and hopefully forever)
in the large reptile tree (LRT, 2324 taxa) Dissacus (Fig 1) now nests alongside Sarcophilus, the extant Tasmanian devil, one or two nodes more primitive from its previous nesting among the mesonychids,

This supports the earlier nesting of mesonychids within the Marsupialia, close to the origin of Placentalia 1, the cat-sized basal placentals (not the small mouse-sized tree shrews in Placentalia 2).

Geographic range
Dissacus is known from North America, Asia and Europe. Sarcophilus is known from fossils and bones across Australia, but living specimens are restricted to Tasmania, an island close to and South of Australia. So ‘devils’ used to be more widespread.

Recently extinct relatives
in the LRT include the Tasmanian wolf, Thylacinus.

Sarcophilus harrisii
(originally Didelphis ursina Harris 1807, then Dasyrurus laniarius Owen 1839, then Boitard 1842, Figs 2, 3) is the extant Tasmanian devil, traditionally considered the largest dasyurid. This is confirmed in the LRT. Following the extinction of Thylacinus in 1936, Sarcophilus became the largest carnivorous marsupial.

Lifestyle and Diet
According to Wikipedia, “It [Sarcophilus] is characterised by its stocky and muscular build, black fur, pungent odour, extremely loud and disturbing screech, keen sense of smell, and ferocity when feeding. The Tasmanian devil’s large head and neck allow it to generate among the strongest bites per unit body mass of any extant predatory land mammal. It hunts prey and scavenges on carrion.”

Reproduction
According to Wikipedia, “Females average four breeding seasons in their life, and give birth to 20 to 30 live young after three weeks’ gestation. The newborn are pink, lack fur, have indistinct facial features, and weigh around 0.20 g (0.0071 oz) at birth. As there are only four nipples in the pouch, competition is fierce, and few newborns survive. The young grow rapidly, and are ejected from the pouch after around 100 days, weighing roughly 200 g (7.1 oz). The young become independent after around nine months.”

Dissacus zanabazari
(Cope 1881; Geisler and McKenna 2007; Early Palaeocene to Early Eocene, Fig 1) was traditionally considered a mesonychid, but here nests with the Tasmanian devil, Sarcophilus, both basal to mesonychids. The post-crania and behavior likely resembled this extant marsupial taxon (Fig 3) lampooned and made famous by Warner Bros cartoons of the 1950s (Fig 4), like ‘Devil May Hare’.

The last common ancestor in the LRT
of devils and rabbits is tiny Late Cretaceous Asiatherium.

This appears to be a novel hypothesis of interrelationships.
If not novel, please provide a citation so I can promote it here. Apologies for not recovering this earlier. Hindsight is 20/20. Learning as I go. Discoveries, like this one, keep happening every day. When discoveries stop, the LRT will be fully resolved… I hope.

References
Boitard P 1842. L’Ursin de Harris. Le Jardin des plantes: Description et mœurs des mammifères de la Ménagerie et du Muséum d’histoire naturelle. Paris: Gustave Barba. p. 204.
Cope ED 1881. On some Mammalia of the lowest Eocene beds of New Mexico. Palaeontological Bulletin 33:484-495.
Harris GP 1807. Description of two new Species of Didelphis from Van Diemen’s Land. Transactions of the Linnean Society of London. 9: 174–78.
Marsh OC 1889. Marsupialia, Cimolestidae. American Journal of Science and Arts 3d ser., XXXVIII, 89, pl. iv, figs. 8–19.

wiki/Sarcophilus Tasmanian devil
wiki/Dissacus

Source: https://pterosaurheresies.wordpress.com/2024/09/03/dissacus-now-a-palaeocene-devil-in-the-lrt/