Magericyon spp.

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Magericyon spp.


Life reconstruction of a Magericyon anceps mother protecting its young. © @ Mauricio Antón->

Temporal range: Neogene; Late Miocene; Late Vallesian (~10-9 Ma)[1]

Scientific classification:

Life
Domain: Eukaryota
(unranked): Unikonta
(unranked): Opisthokonta
(unranked): Holozoa
(unranked): Filozoa
Kingdom: Animalia
Subkingdom: Eumetazoa
(unranked): Bilateria
Clade: Nephrozoa
Superphylum: Deuterostomia
Phylum: Chordata
Clade: Olfactores
Clade: Craniata
Subphylum: Vertebrata
Infraphylum: Gnathostomata
Clade: Eugnathostomata
Clade: Teleostomi
Superclass: Tetrapoda
Clade: Reptiliomorpha
Clade: Amniota
Clade: Synapsida
Clade: Eupelycosauria
Clade: Sphenacodontia
Clade: Sphenacodontoidea
Order: Therapsida
Clade: Eutheriodonta
Suborder: Cynodontia
Clade: Epicynodontia
Infraorder: Eucynodontia
Parvorder: Probainognathia
Superfamily: Chiniquodontoidea
Clade: Prozostrodontia
Clade: Mammaliaformes
Class: Mammalia
Clade: Holotheria
Superlegion: Trechnotheria
Legion: Cladotheria
Sublegion: Zatheria
Infralegion: Tribosphenida
Subclass: Theria
Clade: Eutheria
Infraclass: Placentalia
Subcohort: Exafroplacentalia
Magnorder: Boreoeutheria
Superorder: Laurasiatheria
(unranked): Ferae
(unranked): Carnivoramorpha
Order: Carnivora
Suborder: Caniformia
Family: †Amphicyonidae
Subfamily: †Amphicyoninae
Genus: †Magericyon
Species: †M. anceps
†M. castellanus


Magericyon is a genus of amphicyonid that lived in the the Late Miocene (Vallesian European Land Mammal Age) of Spain, around 10-9 Ma.[1]

Etymology:
Magericyon is named after Magerit, the original name of Madrid. This is a reference to location of the Batallones sites (where Magericyon was discovered) in the Province of Madrid.[2] M. anceps derives its specific name from the Latin word ‘anceps’, meaning trenchant, referencing the dental morphology of the species. M. castellanus was originally referred to the genus Amphicyon.[2]

Description and functional morphology:
Body mass estimates based on complete adult femora put Magericyon anceps’ size between 172-199 kg. Body mass estimates based on total skull length are around 172-205 kg, congruent with femur-based estimates. This puts Magericyon in the same size class with some of the largest known amphicyonines such as Amphicyon, Ischyrochyon, Ysengrinia, and Pseudocyon, all of which weighed more than 150 kg.[2]

M. anceps differs from M. castellanus in having more transversely compressed upper canines, a less transversely elongated second upper molar, and a narrower second lower molar.[2] The upper canines of Magericyon anceps were strongly compressed with crenulated (weakly serrated) edges.[2][3] This compression would have made the canines more fragile to lateral forces, and suggests that M. anceps subdued and killed prey somewhat differently from the plesiomorphic amphicyonine condition (probably delivering cutting bites and avoiding bone). Also, the absence of the first deciduous premolars and adult second premolars, and the strong reduction of the second and third molars and third and fourth premolars indicate that a crushing function of the dentition was reduced. As such, M. anceps shows greater specialization for a hypercarnivorous diet than other amphicyonines.[2]

M. anceps had powerful neck muscles, especially those involved in lateral and rotary movements. The musculus obliquus capitis caudalis was long and thick, as indicated by the expanded atlas wings, which are even more expanded in comparison to felids, ursids, canids, and hyaenids (see figure below).[4]


The atlas wing morphology of M. anceps compared to extant carnivorans; extant carnivorans are shown in a black outline laid over that of Magericyon, and the central part of the atlas in all species is scaled to the same width. A) M. anceps & P. leo, B) M. anceps & C. crocuta, C) M. anceps & U. americanus, D) M. anceps & C. lupus. Note how expanded the wings are compared to those of extant carnivorans.

Both the thickness and marked oblique orientation of this muscle would have increased its ability to stabilize the head and neck while subduing and biting prey. It also would have given the animal strength to tear off pieces of flesh while feeding.[4]


The skull and neck of M. anceps, with red lines and arrows showing the orientation of neck muscles.

The shoulder anatomy of M. anceps was intermediate between that of ursid-like amphicyonines (like A. major) and the cursorial temnocyonines and daphoenines. It was thus likely a more efficient runner than the Middle Miocene A. major and modern bears. The relatively narrow scapular neck suggests it was a very rare climber, with only young Magericyon being any good at it.[3]

However, the remarkably strong and rigid lumbar region (similar to that of Barbourofelis fricki or the modern Mellivora capensis) suggest that Magericyon was still not an especially fast runner, with a relatively low maximum speed while running. While this would have provided some stabilization during running, it was most likely primarily an adaptation for making the back extremely strong, resisting powerful tensions while grappling prey with the powerful forelimbs. The tail was also long and muscular, which would have further helped balance the animal during these activities.[5]

Paleoecology:
Magericyon is known only from the Vallesian sites of Batallones-1 and Batallones-3. It coexisted with three other large carnivorans >150 kg, including the saber-toothed cat Machairodus aphanistus, the bear Indarctos arctoides[4], fellow amphicyonid Ammitocyon kainos, and leopard-sized predators Promegantereon ogygia (another saber-toothed cat), and the ailurid Simocyon batalleri.[4]

Of the four largest predators, Machairodus, Indarctos, and Ammitocyon preferentially consumed the equid Hipparion, judging isotope analyses.[7][8] Only Magericyon deviated from this; it preferred the antelope Austroportax as its prey. It may be that these carnivores were able to coexist and overlap in prey preference (for the most part) as a result of high resource abundance.[7] Also, because Machairodus was a relatively slender felid and much more cursorial than Magericyon, the cat would most likely have inhabited the most open spaces of Batallones, while the bear dog would have preferred vegetated zones and lightly wooded habitats.[4][5]

However, Machairodus aphanistus shows a high sexual dimorphism index among felids, and at 100-240 kg, at least males might have been able to dominate over M. anceps. The bear dog’s ability to powerfully deflesh carcasses would have allowed it to finish meals before kleptoparasites found it.[4]


References:

[1] Domingo, M. S., Alberdi, M. T., Azanza, B., Silva, P. G., & Morales, J. (2013). Origin of an assemblage massively dominated by carnivorans from the Miocene of Spain. PLoS One, 8(5), e63046.
[2] Peigne, S., Salesa, M. J., Anton, M., & Morales, J. (2008). A new Amphicyonine (Carnivora: Amphicyonidae) from the Upper Miocene of Batallones‐1, Madrid, Spain. Palaeontology, 51(4), 943-965.
[3] Siliceo, G., Salesa, M. J., Antón, M., Pastor, J. F., & Morales, J. (2015). Comparative anatomy of the shoulder region in the Late Miocene Amphicyonid Magericyon anceps (Carnivora): functional and paleoecological inferences. Journal of Mammalian Evolution, 22, 243-258.
[4] Siliceo, G., Salesa, M. J., Antón, M., Peigné, S., & Morales, J. (2017). Functional anatomy of the cervical region in the Late Miocene amphicyonid Magericyon anceps (Carnivora, Amphicyonidae): implications for its feeding behaviour. Palaeontology, 60(3), 329-347.
[5] Siliceo, G., Antón, M., Morales, J., & Salesa, M. J. (2020). Built for strength: functional insights from the thoracolumbar and sacrocaudal regions of the late Miocene amphicyonid Magericyon anceps (Carnivora, Amphicyonidae) from Batallones-1 (Madrid, Spain). Journal of Mammalian Evolution, 27, 497-518.
[6] Morales, J., Abella, J., Sanisidro, O., & Valenciano, A. (2021). Ammitocyon kainos gen. et sp. nov., a chimerical amphicyonid (Mammalia, Carnivora) from the late Miocene carnivore traps of Cerro de los Batallones (Madrid, Spain). Journal of Systematic Palaeontology, 19(5), 393-415.
[7] Domingo, L., Domingo, M. S., Koch, P. L., Morales, J., & Alberdi, M. T. (2017). Carnivoran resource and habitat use in the context of a Late Miocene faunal turnover episode. Palaeontology, 60(4), 461-483.
[8] Domingo, M. S., Domingo, L., Badgley, C., Sanisidro, O., & Morales, J. (2013). Resource partitioning among top predators in a Miocene food web. Proceedings of the Royal Society B: Biological Sciences, 280(1750), 20122138.

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Coprolites in natural traps: direct evidence of bone‐eating carnivorans from the Late Miocene Batallones‐3 site, Madrid, Spain

We describe two carnivoran coprolites found in the pseudokarst natural carnivore trap of Batallones‐3, from the Late Miocene of Spain. The larger one, comprising multiple indistinguishable fragments of broken and corroded bones, indicates that the producer of the dropping might have been highly capable of crushing the softer parts of large bones. On the other hand, the smaller one shows several relatively larger and more complete bone fragments, thus exhibiting a greater capacity to break and swallow large portions of bone. The external morphology of the large coprolite is similar to that of extant bears, whereas the smaller one more closely resembles that of the living insectivorous hyaenid Proteles in morphology, on the one hand, and that of the viverrid Genetta in size, on the other hand. We hypothesize that the amphicyonid Magerycion anceps was the producer of the large coprolite and the jackal‐sized basal hyaenid Protictitherium crassum excreted the smaller one. Thus, we present the first direct evidence of a bone durophagous diet in the carnivorans of Batallones.

www.idunn.no/doi/pdf/10.1111/let.12438