scholarly journals Quantitative assessment of tarsal morphology illuminates locomotor behaviour in Palaeocene mammals following the end-Cretaceous mass extinction

2021 ◽  
Vol 288 (1950) ◽  
Author(s):  
Sarah L. Shelley ◽  
Stephen L. Brusatte ◽  
Thomas E. Williamson

Mammals exhibit vast ecological diversity, including a panoply of locomotor behaviours. The foundations of this diversity were established in the Mesozoic, but it was only after the end-Cretaceous mass extinction that mammals began to increase in body size, diversify into many new species and establish the extant orders. Little is known about the palaeobiology of the mammals that diversified immediately after the extinction during the Palaeocene, which are often perceived as ‘archaic’ precursors to extant orders. Here, we investigate the locomotor ecology of Palaeocene mammals using multivariate and disparity analyses. We show that tarsal measurements can be used to infer locomotor mode in extant mammals, and then demonstrate that Palaeocene mammals occupy distinctive regions of tarsal morphospace relative to Cretaceous and extant therian mammals, that is distinguished by their morphological robustness. We find that many Palaeocene species exhibit tarsal morphologies most comparable with morphologies of extant ground-dwelling mammals. Disparity analyses indicate that Palaeocene mammals attained similar morphospace diversity to the extant sample. Our results show that mammals underwent a post-extinction adaptive radiation in tarsal morphology relating to locomotor behaviour by combining a basic eutherian bauplan with anatomical specializations to attain considerable ecomorphological diversity.

2020 ◽  
Vol 29 (2) ◽  
pp. 278-283
Author(s):  
S.G. Ermilov

The oribatid mite subgenus Scheloribates (Topobates) Grandjean, 1958, is recorded from the Neotropical region for the first time. A new species of this subgenus is described from the leaf litter collected in Cayo Agua Island, Panama. Scheloribates (Topobates) panamaensis sp. nov. differs from its related species by the very large body size and presence of a strong ventrodistal process on the leg femora II–IV.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Naoto Jimi ◽  
Shinta Fujimoto ◽  
Mami Takehara ◽  
Satoshi Imura

AbstractThe phylum Annelida exhibits high morphological diversity coupled with its extensive ecological diversity, and the process of its evolution has been an attractive research subject for many researchers. Its representatives are also extensively studied in fields of ecology and developmental biology and important in many other biology related disciplines. The study of biomineralisation is one of them. Some annelid groups are well known to form calcified tubes but other forms of biomineralisation are also known. Herein, we report a new interstitial annelid species with black spicules, Thoracophelia minuta sp. nov., from Yoichi, Hokkaido, Japan. Spicules are minute calcium carbonate inclusions found across the body and in this new species, numerous black rod-like inclusions of calcium-rich composition are distributed in the coelomic cavity. The new species can be distinguished from other known species of the genus by these conspicuous spicules, shape of branchiae and body formula. Further, the new species’ body size is apparently smaller than its congeners. Based on our molecular phylogenetic analysis using 18S and 28S sequences, we discuss the evolutionary significance of the new species’ spicules and also the species' progenetic origin.


2006 ◽  
Vol 273 (1598) ◽  
pp. 2209-2217 ◽  
Author(s):  
Fabian Herder ◽  
Arne W Nolte ◽  
Jobst Pfaender ◽  
Julia Schwarzer ◽  
Renny K Hadiaty ◽  
...  

Adaptive radiations are extremely useful to understand factors driving speciation. A challenge in speciation research is to distinguish forces creating novelties and those relevant to divergence and adaptation. Recently, hybridization has regained major interest as a potential force leading to functional novelty and to the genesis of new species. Here, we show that introgressive hybridization is a prominent phenomenon in the radiation of sailfin silversides (Teleostei: Atheriniformes: Telmatherinidae) inhabiting the ancient Malili Lakes of Sulawesi, correlating conspicuously with patterns of increased diversity. We found the most diverse lacustrine species-group of the radiation to be heavily introgressed by genotypes originating from streams of the lake system, an effect that has masked the primary phylogenetic pattern of the flock. We conclude that hybridization could have acted as a key factor in the generation of the flock's spectacular diversity. To our knowledge, this is the first empirical evidence for massive reticulate evolution within a complex animal radiation.


Nematology ◽  
2008 ◽  
Vol 10 (3) ◽  
pp. 335-346 ◽  
Author(s):  
Hongmei Li ◽  
Phap Quang Trinh ◽  
Lieven Waeyenberge ◽  
Maurice Moens

Abstract Bursaphelenchus chengi sp. n. is described and illustrated. Dauer juveniles were isolated from imported wood packaging materials from Taiwan to Nanjing Port, China. Bursaphelenchus chengi sp. n. was reared and maintained on Petri dish cultures of the fungus Botrytis cinerea. The new species is characterised by the medium body size in both sexes, the presence of only two incisures in the lateral field and the robust and strongly curved spicules. The spicule lamina is angular distally, the rostrum digitate and the condylus rounded. The tail is arcuate with a pointed terminus. The bursa is usually truncate with the posterior margin indented in some specimens or rounded with a fine axial point. Females have a small vulval flap formed by a short extension of the cuticle of the anterior lip, and a conical tail that gradually tapers to an almost straight or slightly recurved, pointed or rounded terminus. Because of the presence of two lateral lines, similar spicule shape, tapering female tail and the presence of a small vulval flap, B. chengi sp. n. should be grouped in the abietinus-group sensu Braasch. together with B. abietinus, B. antoniae, B. hellenicus, B. hylobianum and B. rainulfi. ITS-RFLP profiles support the proposal of the new species, and phylogenetic analysis of the 28S rDNA D2/D3 domain sequence places it close to B. antoniae and other species of the abietinus-group.


Paleobiology ◽  
2007 ◽  
Vol 33 (3) ◽  
pp. 455-468 ◽  
Author(s):  
Marcelo M. Rivadeneira ◽  
Pablo A. Marquet

AbstractWe assessed selective extinction patterns in bivalves during a late Neogene mass extinction event observed along the temperate Pacific coast of South America. The analysis of 99 late Neogene and Quaternary fossil sites (recorded from 7°S to 55°S), yielding ∼2800 occurrences and 118 species, revealed an abrupt decline in Lyellian percentages during the late Neogene–Pleistocene, suggesting the existence of a mass extinction that decimated ∼66% of the original assemblage. Using the late Neogene data set (n = 59 species, 1346 occurrences), we tested whether the extinction was nonrandom according to taxonomic structure, life habit, geographic range, and body size. Our results showed that the number of higher taxa that went extinct was not different than expected by random. At first sight, extinction was selective only according to life habit and geographic range. Nevertheless, when phylogenetic effects were accounted for, body size also showed significant selectivity. In general, epifaunal, small-sized (after phylogenetic correction), and short-ranged species tended to have increased probability of extinction. This is verified by strong interactions between the variables herein analyzed, suggesting the existence of nonlinear effects on extinction chances. In the heavily decimated epifaunal forms, survival was not enhanced by widespread ranges or larger body sizes. Conversely, the widespread and large-sized infaunal forms tended to have lower probability of extinction. Overall, the ultimate extinction of late Neogene bivalve species along the Pacific coast of South America seems to have been determined by a complex interplay of ecological and historical (phylogenetic) effects.


Zootaxa ◽  
2013 ◽  
Vol 3599 (2) ◽  
pp. 178-188 ◽  
Author(s):  
ITAMAR A. MARTINS ◽  
HUSSAM ZAHER

A new species of the genus Holoaden is described from the Atlantic forest of the state of São Paulo, Brazil, being restricted to primary or slightly disturbed high altitude cloud forests along the northeastern portion of the Serra do Mar. The typelocality is determined as Estação Ecológica de Bananal, in the Municipality of Bananal, State of São Paulo, Brazil. The new species is characterized by its moderate body size (female 42.6–44.2 mm SVL; male 37.2–38.5 mm SVL) with long and slender limbs, a head wider than long, a highly glandular dorsum, covered by well developed macroglands that extend to the internasal region, thigh and tibia, and an intense dark brown dorsal coloration and dark grey ventral surface.


Zootaxa ◽  
2021 ◽  
Vol 4920 (1) ◽  
pp. 91-100
Author(s):  
SERGEY G. ERMILOV ◽  
ELIZABETH A. HUGO-COETZEE ◽  
ALEXANDER A. KHAUSTOV

Three new species of oribatid mites of the family Galumnidae are described from soil and coniferous litter of Hogsback State Forest, Eastern Cape Province, South Africa. Pilogalumna hogsbackensis sp. nov. differs from Pilogalumna tenuiclava and P. ornatula by the presence of elongate oval postanal porose area and narrowly unilaterally dilated bothridial head. Pergalumna amatholensis sp. nov. differs from Pergalumna distincta by the presence of smaller body size, rounded rostrum, unilaterally dilated bothridial head, one pair of notogastral porose areas Aa, and the localization of opisthonotal gland opening and lyrifissure im. Stictozetes ihaguensis sp. nov. differs from all species of the genus by presence of bothridial seta with narrowly dilated head and median pore in both genders. An identification key to known species of Stictozetes is presented. 


Zootaxa ◽  
2021 ◽  
Vol 4985 (2) ◽  
Author(s):  
NUO DING ◽  
YI-JIAO LIU ◽  
XIN-YI LIAO ◽  
CHU-ZE SHEN ◽  
ZHU-QING HE

Parapteronemobius contains 7 species or subspecies distributed in East Asia with only one species recorded from China. In this study, we reported the second species, P. chenggong He sp. nov., from Zhejiang. The new species differs from P. dibrachiatus in body size, male genitalia and COI gene. The phylogeny of this genus in subfamily Nemobiinae are discussed based on COI, 18S and 28S genes. The type specimens are deposited in the Museum of Biology, East China Normal University (ECNU).


2021 ◽  
Vol 288 (1960) ◽  
Author(s):  
Pedro M. Monarrez ◽  
Noel A. Heim ◽  
Jonathan L. Payne

Whether mass extinctions and their associated recoveries represent an intensification of background extinction and origination dynamics versus a separate macroevolutionary regime remains a central debate in evolutionary biology. The previous focus has been on extinction, but origination dynamics may be equally or more important for long-term evolutionary outcomes. The evolution of animal body size is an ideal process to test for differences in macroevolutionary regimes, as body size is easily determined, comparable across distantly related taxa and scales with organismal traits. Here, we test for shifts in selectivity between background intervals and the ‘Big Five’ mass extinction events using capture–mark–recapture models. Our body-size data cover 10 203 fossil marine animal genera spanning 10 Linnaean classes with occurrences ranging from Early Ordovician to Late Pleistocene (485–1 Ma). Most classes exhibit differences in both origination and extinction selectivity between background intervals and mass extinctions, with the direction of selectivity varying among classes and overall exhibiting stronger selectivity during origination after mass extinction than extinction during the mass extinction. Thus, not only do mass extinction events shift the marine biosphere into a new macroevolutionary regime, the dynamics of recovery from mass extinction also appear to play an underappreciated role in shaping the biosphere in their aftermath.


Zootaxa ◽  
2016 ◽  
Vol 4208 (3) ◽  
pp. 201
Author(s):  
LAURENCE A. MOUND ◽  
DESLEY J. TREE

The genus Deplorothrips Mound & Walker is recorded from Australia for the first time. The genus is found widely across the continent, and descriptions and an illustrated identification key are provided to 14 new species. These have been found living on dead twigs and branches, particularly of Eucalyptus trees. Typical members of this genus have short maxillary stylets that are scarcely retracted into the head capsule, but some of the species have more deeply retracted stylets. Structural polymorphism is recorded in several species, associated both with sex and with body size. Remarkable variation is recorded for some species in the number of sense cones on the antennal segments. 


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