Browsing by Author "Flynn, John J. (John Joseph), 1955-"

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Chlorocyon phantasma, a late Eocene borhyaenoid (Mammalia, Metatheria, Sparassodonta) from the Los Helados locality, Andean Main Range, central Chile. (American Museum novitates, 0003-0082 ; no. 3918)
(American Museum of Natural History., 2018-12-28) Engelman, Russell K.; Flynn, John J. (John Joseph), 1955-; Gans, Phillip B., 1956-; Wyss, André R.; Croft, Darin A.
Sparassodont metatherians were the dominant terrestrial mammalian predators during South America's long Cenozoic isolation. This group's early fossil record is very poor, however, particularly for the late Eocene and early Oligocene. Here, we describe a new sparassodont, Chlorocyon phantasma, gen. et sp. nov., based on a specimen from Los Helados, a new locality within the Abanico Formation of the Andean Main Range of central Chile. New ⁴⁰Ar/³⁹Ar dates at Los Helados bracketing the fossil-bearing level constrain the age of this specimen to 37-36 Ma (late Eocene), indicating that this new taxon likely pertains to the Mustersan South American Land Mammal "Age." Chlorocyon is the first Paleogene sparassodont reported from Chile and the first sparassodont described from the Abanico Formation. Distinctive features, including a p3 with an anterior edge that is more curved than the posterior edge and the lack of a hypoconulid on m4, suggest that Chlorocyon is a borhyaenoid closely related to Pharsophorus or Plesiofelis, although much smaller. Chlorocyon represents a welcome addition to the sparse record of late Eocene sparassodonts and indicates that the diversity of non-proborhyaenid borhyaenoids prior to the late Oligocene was greater than previously thought.
Open Access
Eomakhaira molossus, a new saber-toothed sparassodont (Metatheria: Thylacosmilinae) from the early Oligocene (?Tinguirirican) Cachapoal locality, Andean Main Range, Chile. (American Museum novitates, no. 3957)
(American Museum of Natural History., 2020-07-17) Engelman, Russell K.; Flynn, John J. (John Joseph), 1955-; Wyss, André R.; Croft, Darin A.
Thylacosmiline sparassodonts (previously recognized as thylacosmilids) are among the most iconic groups of endemic South American Cenozoic mammals due to their distinctive morphology and convergent resemblance to saber-toothed placental carnivores. However, the early evolution of this group and its relationship to other sparassodonts remains poorly understood, primarily because only highly specialized Neogene taxa such as Thylacosmilus, Anachlysictis, and Patagosmilus are well known. Here, we describe a new Paleogene sparassodont, Eomakhaira molossus, from the Cachapoal locality of central Chile, the first sparassodont reported from early Oligocene strata of the Abanico Formation. Eomakhaira shares features with both Neogene thylacosmilines and Paleogene “proborhyaenids,” and phylogenetic analyses recover this taxon as sister to the clade of Patagosmilus + Thylacosmilus. This broader clade, in turn, is nested within the group conventionally termed Proborhyaenidae. Our analyses support prior hypotheses of a close relationship between thylacosmilines and traditionally recognized proborhyaenids and provide the strongest evidence to date that thylacosmilines are proborhyaenids (i.e, the latter name as conventionally used refers to a paraphyletic group). To reflect the internestedness of these taxa, we propose use of Riggs’ (1933) original name Thylacosmilinae for the less inclusive grouping and Proborhyaenidae for the more inclusive one. Saber teeth arose just once among metatherians (among thylacosmilines), perhaps reflecting a developmental constraint related to nonreplacement of canines in metatherians; hypselodonty may have relaxed this potential constraint in thylacosmilines. The occurrence of Eomakhaira in strata of early Oligocene age from the Chilean Andes demonstrates that the stratigraphic range of thylacosmilines spanned almost 30 million years, far surpassing those of saber-toothed placental lineages.
Open Access
Estimating body mass in New World "monkeys" (Platyrrhini, Primates), with a consideration of the Miocene platyrrhine, Chilecebus carrascoensis ; American Museum novitates, no. 3617
(New York, NY : American Museum of Natural History, 2008) Sears, Karen E.; Finarelli, John A.; Flynn, John J. (John Joseph), 1955-; Wyss, André R.
Well-constrained estimates of adult body mass for fossil platyrrhine species (New World "monkeys") are essential for resolving numerous paleobiological questions. However, no consensus exists as to which craniodental measures best correlate with body mass among extant taxa in this clade. In this analysis, we analyze 80 craniodental variables and generate predictive equations applicable to fossil taxa, including the early platyrrhine Chilecebus carrascoensis. We find mandibular length to be the best craniodental predictor of body mass. There is no significant difference in predictive value between osteological and dental measures. Variables associated with the mandible and lower dentition do significantly outperform the cranium and upper dentition. Additionally, we demonstrate that modern platyrrhines differ, morphometrically, from early fossil forms. Chilecebus possesses unusual cranial proportions in several key features, as well as proportionally narrow upper incisors and wide upper cheek teeth. These variables yield widely divergent body mass estimates for Chilecebus, implying that the correlations observed in a crown group cannot be assumed a priori for early diverging fossils. Variables allometrically consistent with those in extant forms yield a body mass estimate of slightly less than 600 grams for Chilecebus, nearly a factor of two smaller than prior preliminary estimates. Scaled to body mass, the brain of Chilecebus is markedly smaller than those of modern anthropoids, despite its lowered body mass estimate advocated here. This finding, in conjunction with a similar pattern exhibited by fossil catarrhines, suggests that increased encephalization arose independently in the two extant subgroups of anthropoids (platyrrhines and catarrhines).
Open Access
High resolution images for 'Postcranial osteology of Azendohsaurus madagaskarensis (?Middle to Upper Triassic, Isalo Group, Madagascar) and its systematic position among stem archosaur reptiles. (Bulletin of the American Museum of Natural History, no. 398)'
(2015) Nesbitt, Sterling J.; Flynn, John J. (John Joseph), 1955-; Pritchard, Adam C., 1987-; Parrish, J. Michael, 1953-; Ranivoharimanana, Lovasoa.; Wyss, André R.
High resolution images for 'Postcranial osteology of Azendohsaurus madagaskarensis (?Middle to Upper Triassic, Isalo Group, Madagascar) and its systematic position among stem archosaur reptiles. (Bulletin of the American Museum of Natural History, no. 398)' - http://hdl.handle.net/2246/6624
Open Access
Hyopsodus (Mammalia) from the Tepee Trail Formation (Eocene), northwestern Wyoming. American Museum novitates ; no. 3007
(New York, N.Y. : American Museum of Natural History, 1991) Flynn, John J. (John Joseph), 1955-
Open Access
Morphological diversity in the postcranial skeleton of Casamayoran (?middle to late Eocene) Notoungulata and foot posture in notoungulates ; American Museum novitates, no. 3601
(New York, NY : American Museum of Natural History, 2007) Shockey, Bruce J.; Flynn, John J. (John Joseph), 1955-
Appendicular skeletons of isotemnid notoungulates are described from Cañadón Vaca (Vacan "subage", Casamayoran South American Land Mammal "Age", ?middle to late Eocene). Simpson documented three of these, Thomashuxleya externa, Anisotemnus distentus, and Pleurostylodon similis, some 70 years ago, in fashioning a composite isotemnid skeleton, but he did not emphasize their differences from one another. We note variation, especially in the forelimb, that appears to be functionally significant as well as phylogenetically informative. For example, the downwardly curved olecranon, ventrally concave bowing of the ulnar shaft, and orthogonally directed articulation of the elbow joint suggest an erect forelimb stance in Thomashuxleya externa, whereas the forelimbs of Anisotemnus distentus and Pleurostylodon similis show indications of a crouching posture, including ventrally convex bowing of the ulnar shaft with a slight upward curvature of the olecranon, and an elbow joint in which the antebrachium rotated obliquely relative to the humerus. Articular facets on the proximal carpals suggest that the manus of Anisotemnus was habitually extended, indicating a plantigrade stance of the forelimb. Although none of these three taxa have associated hindfoot material, all known Vacan notoungulate astragali have shallow trochlea, well developed and deep grooves for the flexor hallucis longus, which are separated from the trochlea by a fossa that contains a superior astragalar foramen. An isolated notoungulate pes, not referred to any of the three taxa above, appears to be pentadactyl, having a distinctive, divergent tarsometatarsal joint for its hallux. It also has a shallow trochlea, an astragalar foramen, and a flexor groove, indicating limited rotation of the upper ankle joint. Indeed, a survey of known Casamayoran-aged notoungulate astragali indicates that most taxa had limited mobility at the tibioastragalar joint, in stark contrast to post-Eocene faunas in which nearly all the ungulates had greater rotation of the upper ankle joint and were subcursorial, as evidenced by their longer and deeper trochlear articulation and loss of the astragalar foramen. We suggest that the change from ambulatory- to subcursorial-dominated ungulate faunas across the Eocene-Oliogocene boundary mirrors the changes from brachydont to hypsodont faunas over the same time. Decreased temperatures and rainfall resulting in more open habitats may be related to both morphological evolutionary patterns.
Open Access
New basal Interatheriidae (Typotheria, Notoungulata, Mammalia) from the Paleogene of central Chile ; American Museum novitates, no. 3520
(New York, NY : American Museum of Natural History, 2006) Hitz, Ralph B., 1964-; Flynn, John J. (John Joseph), 1955-; Wyss, Andre R.
Two new basal interatheriids ("notopithecines") are described from central Chile. Specimens of a new taxon, Johnbell hatcheri, derive from Abanico Formation deposits near Termas del Flaco, in the valley of the Rio Tinguiririca, forming a distinctive element of the Tinguiririca Fauna. The Tinguiririca Fauna, which forms the basis of the recently defined Tinguirirican SALMA, documents the co-occurrence of species of archaic, dentally primitive herbivores and basal members of later diverging groups of more advanced hypsodont forms, and other transitional aspects of mammal evolution near the Eocene/Oligocene boundary. A specimen recovered from the Abanico Formation in the drainage of the Rio Cachapoal (~100 km north of Termas del Flaco), SGOPV 3451 is referred to Johnbell hatcheri. This is the first time a specimen from elsewhere in the central Chilean Main Range has been assigned to a species represented in the stratotype sequence of the Tinguiririca Fauna (upper Rio Tinguiririca Valley). Ignigena minisculus, the other new basal interatheriid recognized herein, is known only from older strata of the Abanico Formation, from the Tapado Fauna within the Rio Tinguiririca Valley, estimated to be Casamayoran in age. Phylogenetic analysis shows these two new basal interatheriids to be outgroups to the Interatheriinae. Both new taxa are smaller than all other interatheriids known, except Punapithecus. Small body size may reflect geographic provincialism, as these diminutive forms are rest[r]icted to more northern latitudes compared to larger basal interatheriids, which derive from Patagonia. SGOPV 3604, from the Abanico Formation along the Rio Azufre, several kilometers north of the Rio Tinguiririca drainage, is referred to the early interatheriid Antepithecus brachystephanus, a taxon otherwise known only from Casamayoran ("late" Barrancan subage) SALMA deposits in Patagonia. A phylogenetic definition for the name Interatheriidae is proposed on the strength of the resolution achieved in the phylogenetic analysis. This analysis also shows clearly that "Notopithecinae" represents a paraphyletic assemblage. We suggest that taxa formerly termed "notopithecines" are more appropriately referred to as "basal interatheriids".
Open Access
New fossil giant panda relatives (Ailuropodinae, Ursidae) : a basal lineage of gigantic Mio-Pliocene cursorial carnivores (American Museum novitates, no. 3996)
(American Museum of Natural History., 2023-03-14) Jiangzhou, Qigao; Flynn, John J. (John Joseph), 1955-; Wang, Shiqi (Paleontologist); Hou, Sukuan; Deng, Tao (Paleontologist)
Among the fossil members of the giant panda subfamily of ursid carnivorans, Ailuropodinae, one group of species is of giant size, those of Indarctos. Indarctos species have some dental resemblances to and may be closely related to Agriotherium, although there are other clear differences between these taxa, and no known species has definitive shared derived traits that could link these two genera. Here we describe a rich suite of fossil material from both North America and eastern Asia, all belonging to a new genus, Huracan, which possesses characters shared with both Agriotherium and Indarctos but also has diagnostic autapomorphies. The new taxon was distributed widely in the Holarctic during the latest Miocene, including at least four species: the type species Huracan schneideri (previously Agriotherium schneideri) from the latest Hemphillian (Hh4) and possibly early Blancan North American Land Mammal “Ages” (NALMAs), North America; H. coffeyi from the early Late Hemphillian (Hh3) NALMA, North America; H. qiui, sp. nov., from the Baodean Asian Land Mammal “Age” (ALMA), northern China; and H. roblesi from the MN13 zone (latest Miocene–earliest Pliocene) of Spain. Huracan is the nearest sister taxon to Agriotherium, the latter herein considered to be an ailuropodine (in the tribe Agriotheriini) rather than a hemicyonid, and the common ancestor of both genera evolved from Indarctos (with resultant paraphyly of that taxon) or another Indarctos-like ailuropodine bear, likely in eastern Asia. The dentitions of Huracan and Agriotherium both are more specialised for carnivory than most Indarctos species, indicating a radiation of diverse ecological carnivores earlier in the history of the later-diverging, highly specialized herbivores in the giant panda lineage. Their postcranial morphology suggests that species in both genera (Huracan and Agriotherium) were more cursorial than species assigned to Indarctos, and thus well adapted to more open habitats. These derived traits may explain the worldwide replacement of Indarctos species by Huracan and Agriotherium species during the latest Miocene, in response to significant global cooling and expansion of C4 grasslands that occurred at that time.
Open Access
New leontiniid Notoungulata (Mammalia) from Chile and Argentina : comparative anatomy, character analysis, and phylogenetic hypotheses. (American Museum novitates, no. 3737)
(American Museum of Natural History., 2012-02-29) Shockey, Bruce J.; Flynn, John J. (John Joseph), 1955-; Croft, Darin A.; Gans, Phillip B., 1956-; Wyss, André R.
Herein we describe and name two new species of leontiniid notoungulates, one being the first known from Chile, the other from the Deseadan South American Land Mammal Age (SALMA) of Patagonia, Argentina. The Chilean leontiniid is from the lower horizons of the Cura-Mallín Formation (Tcm1) at Laguna del Laja in the Andean Main Range of central Chile. This new species, Colpodon antucoensis, is distinguishable from Patagonian species of Colpodon by way of its smaller I2; larger I3 and P1; sharper, V-shaped snout; and squarer upper premolars. The holotype came from a horizon that is constrained below and above by 40Ar/39Ar ages of 19.53 ± 0.60 and 19.25 ± 1.22, respectively, suggesting an age of roughly 19.5 Ma, or a little older ( 19.8 Ma) when corrected for a revised age of the Fish Canyon Tuff standard. Either age is slightly younger than ages reported for the Colhuehuapian SALMA fauna at the Gran Barranca. Taxa from the locality of the holotype of C. antucoensis are few, but they (e.g., the mylodontid sloth, Nematherium, and a lagostomine chinchillid) also suggest a post-Colhuehuapian faunal age. The second leontiniid named in this paper has been known in the literature for over 75 years as Leontinia sp. Several specimens referable to this species were discovered at Pico Truncado (Deseadan SALMA) during the Field Museums first Marshall Field Expedition, led by Elmer Riggs in 1924. This “new” taxon, Elmerriggsia fieldia, is a small-bodied leontiniid, possessing grooved premolar protocones that lack intermediate lingual cingulae, but have well-developed labial cingulids on their lower molars. This new taxon is fairly common at Pico Truncado, in Santa Cruz, Argentina, but we have not encountered it at other localities. The character-taxon matrix that we constructed for this analysis differs from those previously developed for notoungulates by the substantially greater number of postcranial characters used (41). Colbertia magellanica was used as the outgroup in all analyses. Our initial phylogenetic analysis was limited to only taxa traditionally assigned to the Toxodontia. These included a dozen taxa traditionally considered to be leontiniids, two toxodontids, four notohippids, a homalodotheriid, and two isotemnids. The taxa traditionally classified as leontiniids formed a monophyletic group, in which V-shaped muzzle, caniniform i3, femur with medial suprapatellar ridge, and large wedge-shaped fibular facet of the calcaneum were unequivocal synapomorphies. Colpodon spp. nested within a clade that includes the “tropical” leontiniids, Taubatherium and Huilatherium. Toxodontids and notohippids formed a monophyletic group sister to the leontiniids, with these two clades forming a more inclusive clade that previously had been called the “advanced Toxodontia.” However, when five species of typotheres from three “families” were added to the analysis, the “notohippid” Eurygenium was identified as the nearest outgroup of leontiniids and an “advanced notohippid” plus toxodontid clade (nodes C + F). Unequivocal synapomorphies uniting these two nodes were robust calcanonavicular articulation (“reverse alternating tarsus” as evidenced by a distinct navicular facet on the calcaneum) and a distal radius with a styloid process. The presence of an entolophid fossettid in the lower molars and the downturned olecranon process of the ulna were equivocal synapomorphies for this clade. Though lacking the character states that diagnose a more exclusive “notohippid-toxodontid-leontiniid” clade, Eurygenium shared several unequivocal synapomorphies that unite it with these taxa. These include a well-formed fossette of upper molars formed by the posterior cingulum, absence of an entepicondylar foramen of the humerus, lack of a neck on the astragalus, a transversely elongated astragalar head, and absence of the “astragalar buttress” of the navicular. Unconventionally, the interatheriids used in the analysis (Federicoanaya and Protypotherium, both interatheriine interatheriids) formed the sister group to the taxa traditionally considered to be the “advanced Toxodontia.” Unequivocal synapomorphies uniting these interatheriids with the “advanced Toxodontia” are exclusively postcranial: tetradactyl manus, quadrate fibular facet of the calcaneum, calcaneonavicular contact (without well-formed facet on the calcaneum), and union of the groove for the tendon of the flexor hallucis longus with the astragalar trochlea. Steeply inclined ectal facets of the astragalus and calcaneum are equivocal synapomorphies (shared with Eurygenium, the notohippids, and toxodontids, but not leontiniids). Inclusion of postcranial characters in the phylogenetic analysis illustrates an otherwise undetectable conflict—that of homoplasy-homology discordance between dental and postcranial characters of interatheriine interatheriids (the postcranial skeleton of “notopithicine” interatheriids [or “basal interatheriids” of Hitz et al., 2006] remain unknown). This conflict does not simply represent an arcane point, but has relevance regarding reconstructing the interrelation-ships of several major groups of notoungulates. Other findings of this work include a northerly extension of the geographical range of Colpodon and a possible temporal extension beyond the Colhuehuapian SALMA. It appears that the fauna at Laguna del Laja is an important source of information regarding the faunal transition that occurred between Colhuehuapian and Santacrucian SALMA faunas.
Open Access
New notoungulates (Notostylopidae and basal toxodontians) from the early Oligocene Tinguiririca fauna of the Andean Main Range, central Chile. (American Museum novitates, no. 3841)
(American Museum of Natural History., 2015-11-17) Bradham, Jennifer.; Flynn, John J. (John Joseph), 1955-; Croft, Darin A.; Wyss, André R.
Here we describe two new notoungulate taxa from early Oligocene deposits of the Abanico Formation in the eastern Tinguiririca valley of the Andes of central Chile, including a notostylopid (gen. et sp. nov.) and three basal toxodontians, cf. Homalodotheriidae, one of which is formally named a new species. The valley's eponymous fossil mammal fauna became the basis for recognizing a new South American Land Mammal "Age" intervening between the Mustersan and Deseadan of the classical SALMA sequence, the Tinguirirican. As a temporal intermediate between the bracketing SALMAs (Deseadan and Mustersan), the Tinguirirican is characterized by a unique cooccurrence of taxa otherwise known either from demonstrably younger or more ancient deposits, as well as some taxa with temporal ranges restricted to this SALMA. In this regard, two of the notoungulates described here make their last known stratigraphic appearances in the Tinguiririca Fauna, Chilestylops davidsoni (gen. et sp. nov.), the youngest notostylopid known, and Periphragnis vicentei (sp. nov.), an early diverging toxodontian, the youngest representative of the genus. A second species of Periphragnis from the Tinguiririca valley is provisionally described as Periphragnis, sp. nov., but is not formally named due to its currently poor representation. A specimen referred to Trigonolophodon sp. cf. T. elegans also is described. This taxon is noteworthy for also being reported from Santiago Roth's long perplexing fauna from Cañadón Blanco, now considered Tinguirirican in age. A phylogenetic analysis of notostylopids identifies Chilestylops as closely related to Boreastylops lumbrerensis from northern Argentina.
Open Access
New Paleogene notohippids and leontiniids (Toxodontia, Notoungulata, Mammalia) from the early Oligocene Tinguiririca Fauna of the Andean Main Range, central Chile. (American Museum novitates, no. 3903)
(American Museum of Natural History., 2018-06-25) Wyss, André R.; Flynn, John J. (John Joseph), 1955-; Croft, Darin A.
Here we describe three new notohippid notoungulate species from the early Oligocene-aged Tinguiririca Fauna (Tinguirirican SALMA), recovered from volcaniclastic deposits of the Abanico Formation in the central Chilean Andes, two of which are known from material sufficiently complete to warrant formal naming. These include Eomorphippus bondi, sp. nov., a form of moderate size distinguished by hypsodont incisors and cheekteeth, as well as distinctive proportions of the upper incisors. A closely similar but more diminutive form is described as Eomorphippus neilopdykei, sp. nov. A third previously unrecognized notohippid in the Tinguiririca Fauna, best represented by a large, low-crowned, lower incisor battery, almost certainly represents a new taxon, but remains too fragmentary to warrant naming now. We also propose a new binomial for a previously named notohippid, ?Eomorphippus pascuali, originally described from Gran Barranca in Argentina but which is now also recorded in Chile. This taxon, here named Rosendo pascuali, is markedly less hypsodont than E. bondi and E. neilopdykei and retains lingual cingula on at least p4-m1. As least one leontiniid notoungulate occurs in the Tinguiririca Fauna, Termastherium flacoensis, gen. et sp. nov., best represented by two partial upper cheek toothrows and a tentatively referred maxillary fragment bearing three deciduous teeth. Collectively, description of these new fossils from Termas del Flaco, Chile helps to more fully characterize the Tinguiririca Fauna, facilitating correlation and comparison to other South American land mammal faunas spanning the Eocene-Oligocene transition.
Open Access
Paleogene mammals from the Andes of central Chile : a preliminary taxonomic, biostratigraphic, and geochronologic assessment. American Museum novitates ; no. 3098
(New York, N.Y. : American Museum of Natural History, 1994) Wyss, André R.; Flynn, John J. (John Joseph), 1955-; Norell, Mark.; Swisher, Carl Celso.; Novacek, Michael J.; McKenna, M. C.; Charrier, R.
Open Access
Paleogene pseudoglyptodont xenarthrans from central Chile and Argentine Patagonia ; American Museum novitates, no. 3536
(New York, NY : American Museum of Natural History, 2006) McKenna, Malcolm C.; Wyss, André R.; Flynn, John J. (John Joseph), 1955-
Herein we describe a new, large-bodied species of Pseudoglyptodon, a close sloth ally, from volcaniclastic deposits of the Abanico (= Coya-Machalí) Formation of the central Chilean Andean main range. This species, P. chilensis, is a rare element of the Tinguiririca Fauna, on which the recently formalized Tinguirirican South American land mammal 'age' is founded, being known from just two specimens. The holotype of P. chilensis, a partial skull and largely complete mandibles (preserving seemingly complete upper and lower dentitions), is by far the best-preserved specimen referable to Pseudoglyptodon known. As such, this material permits a more refined phylogenetic placement of this enigmatic xenarthran than has been possible previously, with Pseudoglyptodon representing the proximal outgroup to the clade including the most recent common ancestor of Choelepus and Bradypus, plus all its descendants (i.e., crown clade sloths). A fragmentary specimen from Argentina is removed from Glyptatelus and referred to Pseudoglyptodon. Although this specimen is distinct from P. chilensis and other previously recognized species of Pseudoglyptodon, it offers too meager a basis for formally establishing a new name. Finally, phylogenetic definitions of the names Phyllophaga and Tardigrada are proposed. Historically these terms have been used largely interchangeably, but here we advocate linking the latter to the crown clade.
Open Access
Paleontology and geochronology of the Deseadan ‪(‬late Oligocene‪)‬ of Moquegua, Perú. (American Museum novitates, no. 3668)
(New York, NY : American Museum of Natural History., 2009) Shockey, Bruce J.; Salas-Gismondi, Rodolfo.; Gans, Phillip B., 1956-; Jeong, Annie, 1987-; Flynn, John J. (John Joseph), 1955-
Subsequent to our initial reports of the discovery of Deseadan fossils in southern Perú, we have obtained new data regarding the paleontology and geology of the upper member of the Moquegua Formation. These data include newly recovered fossil specimens and further analyses of those collected in our earlier field seasons. We have also obtained an ash directly from within the fossil-bearing units near the summit of Cerro Pan de Azúcar. Biotites from this Sugarloaf ash give an age estimate of 26.25 ± 0.10 Ma, thus supporting our previous suggestion that these fossil-bearing horizons are of late Oligocene age ‪(‬Deseadan South American Land Mammal Age‪)‬ and removing our query regarding a possible early Miocene age. Most of the fossils are of notoungulates and most of these are trachytheriine mesotheriids. Remarkably, three distinct mesotheriid taxa appear to have been present in the Moquegua fauna, none of which are referable to the common Trachytherus alloxus of the nearby and at least partly contemporaneous Salla beds of Bolivia. Other fossils documented here include postcranial elements of the notohippid notoungulate, Moqueguahippus, a macraucheniid litoptern ‪(‬cf. Coniopternium‪)‬, an osteoderm of an unnamed species of armadillo ‪(‬Dasypodidae, cf. Dasypodinae‪)‬, and a claw of a phorusrhacid bird. We also describe a diminutive new hystricognath rodent, Sallamys quispea, sp. nov. It is similar to, but distinct from, S. pascuali of Salla. Indeed, despite the temporal and geographic proximity of Moquegua to Salla, none of the taxa from Moquegua that can be identified to species are known from Salla. Likewise, we have failed to find any dasypodids from Salla that have osteoderms like that described in this work. Thus, it is appears that distinctive paleogeographic and paleoenvironmental conditions in the late Oligocene led to a regional biotic differentiation for the Moquegua area of coastal Perú.
Open Access
Phylogeny of early Tertiary Carnivora : with a description of a new species of Protictis from the Middle Eocene of northwestern Wyoming. American Museum novitates ; no. 2725
(New York, N.Y. : American Museum of Natural History, 1982) Flynn, John J. (John Joseph), 1955-; Galiano, Henry.
Open Access
Postcranial osteology of Azendohsaurus madagaskarensis (?Middle to Upper Triassic, Isalo Group, Madagascar) and its systematic position among stem archosaur reptiles. (Bulletin of the American Museum of Natural History, no. 398)
(American Museum of Natural History., 2015-12-07) Nesbitt, Sterling J.; Flynn, John J. (John Joseph), 1955-; Pritchard, Adam C., 1987-; Parrish, J. Michael, 1953-; Ranivoharimanana, Lovasoa.; Wyss, André R.
During the Triassic, archosauromorphs became one of the first groups of diapsid reptiles to diversify in terms of body size and morphological disparity in both terrestrial and marine ecosystems across Pangaea. This seemingly rapid divergence, and the numerous unique body plans stemming from it, concomitantly has confounded reconstructions of archosauromorph relationships. Teasing apart homology from homoplasy of anatomical characters in this broad suite of body types remains an enormous challenge with the current sample of taxa. Here, we present the postcranial anatomy of Azendohsaurus madagaskarensis, an early archosauromorph from ?Middle to Upper Triassic strata of Madagascar. Azendohsaurus madagaskarensis is known from nearly the entire skeleton in an ontogenetically variable sample. The holotype locality consists of a monotypic bone bed; preservation ranges from complete but disarticulated bones to articulated sections of the skeleton. Azendohsaurus madagaskarensis embodies an aberrant constellation of archosauromorph features, including an elongated neck, a short, stocky tail, robust limbs, and unexpectedly short digits terminating in large recurved unguals on the manus and pes. Together with the cranium, the postcrania reveal A. madagaskarensis to be another representative of a growing coterie of highly apomorphic and bizarre Triassic archosauromorphs. At the same time, recovery and description of the full anatomy of A. madagaskarensis helps to identify a monophyletic grouping of specialized taxa that includes the North American Late Triassic-aged archosauromorphs Trilophosaurus, Spinosuchus, and Teraterpeton, Indian Pamelaria, and Moroccan Azendohsaurus laaroussii. Moreover, information derived from the skeleton of A. madagaskarensis solidifies the systematic position of these taxa among other archosauromorphs. Using the most comprehensively sampled phylogenetic analysis of early archosauromorphs, we found the clade encompassing the aforementioned taxa as the nearest outgroup of Prolacerta broomi + Archosauriformes. The newly recognized clade containing Azendohsaurus, Trilophosaurus, Spinosuchus, Pamelaria, and Teraterpeton demonstrates high morphological disparity even within a closely related group of archosauromorphs, underscores the polyphyly of protorosaurs (5 prolacertiforms), and suggests that most major divergences within this group occurred in the Triassic. Furthermore, our results indicate that craniodental character states ascribed to a herbivorous diet were much more pervasive across Triassic Archosauromorpha than previously conjectured.
Open Access
Supplemental Material for 'Eomakhaira molossus, a new saber-toothed sparassodont (Metatheria: Thylacosmilinae) from the early Oligocene (?Tinguirirican) Cachapoal locality, Andean Main Range, Chile (American Museum novitates, no. 3957)'
(American Museum of Natural History., 2020-07-17) Engelman, Russell K.; Flynn, John J. (John Joseph), 1955-; Wyss, André R.; Croft, Darin A.
Supplemental Material for 'Eomakhaira molossus, a new saber-toothed sparassodont (Metatheria: Thylacosmilinae) from the early Oligocene (?Tinguirirican) Cachapoal locality, Andean Main Range, Chile (American Museum novitates, no. 3957)'
Open Access
Supplemental Material for 'New fossil giant panda relatives (Ailuropodinae, Ursidae) : a basal lineage of gigantic Mio-Pliocene cursorial carnivores (American Museum novitates, no. 3996)'
(New York, NY : American Museum of Natural History, 2023-03-14) Jiangzhou, Qigao; Flynn, John J. (John Joseph), 1955-; Wang, Shiqi (Paleontologist); Hou, Sukuan; Deng, Tao (Paleontologist)
Supplemental Material for 'New fossil giant panda relatives (Ailuropodinae, Ursidae) : a basal lineage of gigantic Mio-Pliocene cursorial carnivores (American Museum novitates, no. 3996)' - https://digitallibrary.amnh.org/handle/2246/7315
Open Access
Tributes to Malcolm C. McKenna : his students, his legacy. Bulletin of the AMNH ; no. 285
(New York, NY : American Museum of Natural History, 2004) Gould, Gina C.; Bell, Susan K.; Mellett, James Silvan, 1936-; Kellner, Alexander Wilhelm Armin.; Rich, Thomas H. V.; Rich, Pat Vickers.; Engelmann, George F.; Cifelli, Richard.; Flynn, John J. (John Joseph), 1955-; Wyss, André R.; Meng, Jin (Paleontologist); Van Valen, Leigh.; Carrasco, Marc A.; Emry, Robert J.; Hunt, Robert M., Jr., 1941-; Rothwell, Tom.; Geisler, Jonathan H.; Gabbert, Sherri L.; Coombs, Margery Chalifoux.; Evander, Robert Lane, 1948-; MacFadden, Bruce J.; Prothero, Donald R.
Open Access
Two new taxa (Caviomorpha, Rodentia) from the early Oligocene Tinguiririca fauna (Chile). (American Museum novitates, no. 3750)
(American Museum of Natural History., 2012-07-20) Bertrand, Ornella C.; Flynn, John J. (John Joseph), 1955-; Croft, Darin A.; Wyss, André R.
Here we describe two new caviomorphs from the early Oligocene Tinguiririca fauna of the Andean Main Range of central Chile, representing the most ancient rodents known from the mid to high latitudes of South America, and the second-oldest securely dated rodents from the continent. These two new taxa are each documented by single partial mandibles bearing largely complete dentitions. Representing two new taxa, Andemys termasi, gen. et sp. nov., and Eoviscaccia frassinettii, sp. nov., these caviomorphs are informally referred to the pan-Dasyproctidae and pan-Chinchillidae, respectively. These taxa, together with recent findings in Peru, confirm that caviomorphs were well diversified prior to the Deseadan SALMA, that they likely originated during the middle to late Eocene, but that they did not spread from the tropics until some time after the Mustersan--a well-sampled interval from which rodents are unknown in higher latitudes. Additionally, in documenting the earliest occurrence of hypsodonty among caviomorphs Eoviscaccia frassinettii, sp. nov., provides important insights into the acquisition of this common mammalian dental innovation in rodents.