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New fossil giant panda relatives (Ailuropodinae, Ursidae) : a basal lineage of gigantic Mio-Pliocene cursorial carnivores (American Museum novitates, no. 3996)
Full text link71 pages : illustrations (chiefly color), color maps ; 26 cm.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
Systematic revision of the whip spider family Paracharontidae (Arachnida: Amblypygi) with description of a new troglobitic genus and species from Colombia (American Museum novitates, no. 4000)
Full text link36 pages : illustrations (some color), map ; 26 cm.The ancient, enigmatic whip spider family Paracharontidae Weygoldt, 1996, representing the basalmost lineage of the arachnid order Amblypygi Thorell, 1883, is revised. The monotypic West African genus Paracharon Hansen, 1921, from Guinea Bissau, is redescribed, based on a reexamination and reinterpretation of the newly designated lectotype. A new troglobitic whip spider, Jorottui ipuanai, gen. et sp. nov., is described from a cave system in the upper basin of the Camarones River in the La Guajira Department of northeastern Colombia. This new taxon is the second extant representative of Paracharontidae and the first outside Africa. It is unambiguously assigned to the family based on several characters shared with Paracharon caecus Hansen, 1921, notably a projection of the anterior carapace margin, the tritosternum not projecting anteriorly, similar pedipalp spination, a reduced number of trichobothria on the tibia of leg IV, and cushionlike female gonopods. A detailed examination confirmed the absence of ocelli in both genera and the presence of three (Paracharon) vs. four (Jorottui, gen. nov.) prolateral teeth on the basal segment of the chelicera, the dorsalmost tooth bicuspid in both genera. The male gonopods of Paracharontidae are described for the first time. Paracharonopsis cambayensis Engel and Grimaldi, 2014, is removed from Paracharontidae and placed incertae sedis in Euamblypygi Weygoldt, 1996; amended, comparative diagnoses are presented for Paracharontidae and Paracharon; and previous interpretations of various diagnostic characters for Paracharontidae are discussed
Systematic revision of Thomasomys cinereus (Rodentia: Cricetidae: Sigmodontinae) from northern Peru and southern Ecuador, with descriptions of three new species (Bulletin of the American Museum of Natural History, no. 461)
Full text link71 pages : color illustrations, map ; 26 cm.Thomasomys cinereus is the type species of Thomasomys, type genus of the sigmodontine tribe Thomasomyini. As currently recognized, Thomasomys includes 48 species, all of which are endemic to humid montane or premontane forests in the tropical Andes. Although it has been suggested that T. cinereus is a species complex, this hypothesis has yet to be critically evaluated. Herein we provide a revision of the species based on a qualitative assessment of external, craniodental, and soft morphological traits; morphometric analyses; a phylogenetic analysis based on cytochrome b gene sequences; species delimitation methods; and first-hand examination of type material. Our analyses of genetic data recovered four distinct clades within T. cinereus, one corresponding to T. cinereus sensu stricto (restricted to the montane forests delimited by the Río Marañón, Río Huancabamba, and Río Tablachaca in Cajamarca department, Peru) and three new species: Thomasomys lojapiuranus, sp. nov., from the montane forests of Piura department, Peru, and Loja province, Ecuador; T. shallqukucha, sp. nov., restricted to the Kañaris montane forests in the Peruvian department of Lambayeque; and T. pagaibambensis, sp. nov., restricted to the montane forests of Pagaibamba in Cajamarca department, Peru. These species can be distinguished by several discrete morphological traits of the skull, dentition, mandible, stomach, palatal rugae, and glans penis. Genetic distances among these taxa range from 5.06%–7.65% at the cytochrome b locus, and delimitation analyses based on cytochrome b sequence data support their recognition as distinct species. Our results suggest the existence of previously unsuspected dispersal barriers in the Andes of northern Peru, and they confirm that the Río Marañón is a formidable barrier that limits the distribution of species of Thomasomys as well as other sigmodontine rodents
A key to the Pacific genera of Eumeninae (Hymenoptera: Vespidae) (American Museum novitates, no. 3995)
No full text16 pages : illustrations ; 26 cm.A key to the genera of the Eumeninae occurring in Oceania is presented. Hitherto there has been no published key to these genera, making routine identification difficult. New combinations are Pararrhynchium atrum emifasciatum (Giordani Soika), Pararrhynchium simillimum (Giordani Soika), Parodynerus mariannensis (Bequaert and Yasumatsu), and Phimenes solomonis malaitensis (van der Vecht)
New discovery of rhyncholites and conchorhynchs (cephalopod jaw elements) from the Upper Cretaceous Mount Laurel Formation of Delaware (American Museum novitates, no. 3998)
Full text link20 pages : illustrations (some color), map ; 26 cm.Rhyncholites and Conchorhynchs are the calcitic elements of upper and lower jaws of cephalopods, respectively. Rhyncholites and conchorhynchs occur in relatively high abundance and are widely distributed, with a long geological range, extending from the Triassic to the Miocene. While rhyncholites and conchorhynchs are relatively common in Europe, there are only a few reports from North America. Here, we document 24 specimens of rhyncholites and 12 specimens of conchorhynchs from the Upper Cretaceous Mount Laurel Formation in Delaware. The specimens were found in isolation and, thus, identifying the taxon to which the rhyncholites and conchorhynchs belong is difficult. However, the Cretaceous nautilid Eutrephoceras occurs in the same formation, suggesting that the rhyncholites and conchorhynchs may belong to this taxon. We performed a morphometric analysis of these structures based on linear measurements. Our results reveal that some morphological parameters in rhyncholites are correlated with size. Additionally, our specimens exhibit high intraspecific variation, which may have been overlooked in previous studies
Supplemental material for 'Cranial and postcranial morphology of the insectivoran-grade mammals Hsiangolestes and Naranius (Mammalia, Eutheria) : with analyses of their phylogenetic relationships (Bulletin of the American Museum of Natural History, no. 463)'
No full textSupplemental material for 'Cranial and postcranial morphology of the insectivoran-grade mammals Hsiangolestes and Naranius (Mammalia, Eutheria) : with analyses of their phylogenetic relationships (Bulletin of the American Museum of Natural History, no. 463) - https://digitallibrary.amnh.org/handle/2246/732
Supplemental Material for 'New discovery of rhyncholites and conchorhynchs (cephalopod jaw elements) from the Upper Cretaceous Mount Laurel Formation of Delaware (American Museum novitates, no. 3998)'
No full textSupplemental Material for 'New discovery of rhyncholites and conchorhynchs (cephalopod jaw elements) from the Upper Cretaceous Mount Laurel Formation of Delaware (American Museum novitates, no. 3998)' - https://digitallibrary.amnh.org/handle/2246/731
Cranial and postcranial morphology of the insectivoran-grade mammals Hsiangolestes and Naranius (Mammalia, Eutheria) : with analyses of their phylogenetic relationships (Bulletin of the American Museum of Natural History, no. 463)
No full text127 pages : illustrations (chiefly color), color map ; 26 cm.Early Cenozoic “insectivorans” possess some of the most primitive morphologies among eutherian mammals. Studies of these archaic mammals offer insights into the early diversifications of basal eutherians. Despite such importance, early fossil “insectivorans” from Asia are poorly known due to a scarcity of fossil remains, which often consist only of fragmentary jaws and teeth. Discoveries of remarkably well-preserved fossil “insectivorans”, including complete skulls and articulated postcranial skeletons, from the early Eocene Hengyang Basin in south-central Hunan Province, China, offer a rare opportunity to thoroughly study two taxa belonging to different families. Fine-grained red beds from Hengyang Basin preserve extraordinary fossils with morphological structures rarely seen elsewhere. Thin sections of a skull of Hsiangolestes youngi Zheng and Huang, 1984, for example, reveal the extremely delicate nasal and maxillary turbinates, which, as far as we are aware, are the first known from fossils of this age. We thus take this opportunity to document in detail the cranial and dental morphology, as well as postcranial skeletons, of the Hengyang “insectivorans”. In this monograph, we describe several complete skulls and serial sections of a skull, as well as many partial skulls, mandibles, and postcranial skeletons of Hsiangolestes youngi, an Asian early Eocene insectivoran-grade mammal. We also report a new species of Naranius Russell and Dashzeveg, 1986—N. hengdongensis—an Asian early Eocene cimolestid and describe its well-preserved skulls and mandibles. Hsiangolestes is endemic to Asia. It is currently known only from the earliest Eocene Lingcha Formation, Hengyang Basin, Hunan Province, China. Naranius closely resembles Cimolestes Marsh, 1889, the type genus of the family Cimolestidae. It is mainly distributed in Asia and known from the earliest Eocene deposits in the Bumban Member of the Naran Bulak Formation, Nemegt Basin, of Mongolia, and the Lingcha Formation, Hengyang Basin, Hunan Province, China. The only record of Naranius reported outside of Asia is N. americanus from the early Wasatchian Red Hot Local Fauna, Mississippi, United States. Using PAUP and TNT search algorithms, we place these Hengyang taxa within phylogenetic context of other fossil “insectivorans” from the Mesozoic and early Cenozoic of Asia together with some well-known Holarctic taxa. A phylogenetic analysis of 290 cranial and dental characters from 36 fossil and modern insectivoran-grade taxa is presented, focusing on new materials of Hsiangolestes youngi and Naranius hengdongensis. Based on the results of our phylogenetic analyses, we propose that (1) Hsiangolestes, Prosarcodon, Sarcodon, and Sinosinopa, form a monophyletic group, for which we propose the family name Sarcodontidae; (2) the family Cimolestidae should be restricted to Naranius and Cimolestes, which are sister taxa; (3) the systematic position of Naranius americanus is uncertain; and (4) the family Micropternodontidae should be restricted to Micropternodus and its allies in North America
Supplemental Material for "Gill function in an early arthropod and the widespread adoption of the countercurrent exchange mechanism"
No full textSupplemental Material for: Jin-bo Hou, et. al. (2023) Gill function in an early arthropod and the widespread adoption of the countercurrent exchange mechanism. Royal Society Open Science, 10: 230341. doi: http://doi.org/10.1098/rsos.230341
Exceptional species diversity of Drosophilidae (Diptera) in a neotropical forest (American Museum novitates, no. 3997)
Full text link28 pages : color illustrations, color maps ; 26 cm.The highest single-site species diversity known thus far in the world for Drosophilidae is in Costa Rica, based on findings in this report. A total of 352 species of Drosophilidae (Diptera) were found in a cloud forest (1580 m) in Zurquí de Moravia, San José Province (hereafter “Zurquí”), based on 2908 specimens collected continuously for one year, using eight trapping and collecting methods. There are currently 305 described species from Costa Rica. Zurquí is at the edge of a large, protected area and was the site of an All-Diptera inventory project. For this study, drosophilid specimens were identified to genus/subgenus, sorted to morphospecies, and their abundances plotted by collection method: Malaise traps, flight intercept traps, baited traps, light and yellow pan traps, emergence traps, and hand collecting with nets. The standard method used by drosophilists, bait trapping, captured a small fraction of species. Malaise traps captured 87% of all species, and 41% of the 352 species were captured only this way. Emergence traps captured a surprising diversity (47 species) of Diathoneura and Drosophila, establishing that leaf litter/humus is an important breeding site for some taxa. Combining all collection methods, 11 species were abundant, as defined by 50 or more specimens, and comprised 35% of all specimens in the study; two-thirds (66%) of all species were rare, as defined by five or fewer specimens. Comparisons are made to other well-collected sites and regions around the world. Lowland to mid-montane forests on the eastern slopes of the Andes may be the most diverse area for Drosophilidae, a family that is exemplary for studying the ecology and evolution of tropical diversity