scholarly journals Two braincases of Daspletosaurus (Theropoda: Tyrannosauridae): anatomy and comparison1

2021 ◽  
Vol 58 (9) ◽  
pp. 885-910 ◽  
Author(s):  
Ariana Paulina Carabajal ◽  
Philip J. Currie ◽  
Thomas W. Dudgeon ◽  
Hans C.E. Larsson ◽  
Tetsuto Miyashita
Keyword(s):  
Body Size ◽  
Computerized Tomography ◽  
Distinct Species ◽  
Comprehensive Approach ◽  
Morphological Variations ◽  
Carotid Canal ◽  
New Information ◽  
Individual Variations ◽  
Southern Alberta ◽  
Character Complexes

For sheer complexity, braincases are generally considered anatomically conservative. However, recent research on the braincases of tyrannosaurids have revealed extensive morphological variations. This line of inquiry has its root in Dale Russell’s review of tyrannosaurids in which he established Daspletosaurus torosus — a large tyrannosaurine from the Campanian of southern Alberta. In the wake of systematic revisions to tyrannosaurines previously assigned to Daspletosaurus, one potentially distinct species remains undescribed. This paper describes and compares a braincase referable to this species with that of the holotype for Daspletosaurus torosus using computerized-tomography-based reconstructions. The two braincases have numerous differences externally and internally. The specimen of Daspletosaurus sp. has a bottlenecked olfactory tract, short and vertical lagena, and a developed ascending column of the anterior tympanic recess. The holotype of Daspletosaurus torosus has many unusual traits, including an anteriorly positioned trochlear root, elongate common carotid canal, distinct chamber of the basisphenoid recess, asymmetry in the internal basipterygoid aperture, and laterally reduced but medially expanded subcondylar recess. This comparison also identified characters that potentially unite the two species of Daspletosaurus, including deep midbrain flexures in the endocasts. However, many character variations in the braincases are known in other tyrannosaurids to correlate with body size and maturity, or represent individual variations. Therefore, taxonomic and phylogenetic signals can be isolated from background variations in a more comprehensive approach by using additional specimens. New information on the two braincases of Daspletosaurus is consistent with the emerging view of tyrannosaurid braincases as highly variable, ontogenetically dynamic character complexes.

New Oligaphorura species (Collembola: Onychiuridae) from the forests of East Asia

Zootaxa ◽  
2019 ◽  
Vol 4661 (2) ◽  
pp. 256-270
Author(s):  
XIN SUN ◽  
YU. B. SHVEENKOVA ◽  
ZHIJING XIE ◽  
A. B. BABENKO
Keyword(s):  
New Species ◽  
Body Size ◽  
East Asia ◽  
Russian Far East ◽  
Far East ◽  
Distinct Species ◽  
Species Group ◽  
The Other ◽  
Altai Mountains ◽  
Three New Species

Three new species of the genus Oligaphorura are described from southwestern China (O. wanglangensis sp. nov.) and Russian Far East (O. ussurica sp. nov. and O. kedroviensis sp. nov.). The first species is most similar to O. inya (Weiner & Kaprus’, 2014) known from the Altai Mountains, and can be distinguished from the latter by larger body size and the number of ventral psx (00/000/121101m in O. wanglangensis sp. nov. vs 1/000/212101m in O. inya). The other two species, together with O. montana Weiner, 1994, O. pseudomontana Sun & Wu, 2012 and O. chankaensis Sun & Wu, 2012, form a distinct species-group characterized by the presence of 4+4 pso on antennal base and full-sized anal spines. Both these new species differ from the known congeners of this group by having only 2+2 posterior pso on the head. O. ussurica sp. nov. and O. kedroviensis sp. nov. can be separated due to different number of abdominal pso, i.e. 5(6)5554 in the former vs 44454 in the latter species.

Late Cambrian ptychaspidid trilobites from western Utah: implications for trilobite systematics and biostratigraphy

2005 ◽  
Vol 142 (4) ◽  
pp. 377-398 ◽  
Author(s):  
J. M. ADRAIN ◽  
S. R. WESTROP
Keyword(s):  
North America ◽  
Distinct Species ◽  
Western North America ◽  
Closely Related Species ◽  
Widespread Species ◽  
Late Cambrian ◽  
South Central ◽  
New Information ◽  
The Family ◽  
Notch Peak

The Notch Peak Formation (Late Cambrian, Sunwaptan) of western Utah yields diverse silicified trilobite faunas that provide new information on the anatomy of many taxa. The family Ptychaspididae Raymond, 1924, is represented by species of Keithiella Rasetti, 1944; Idiomesus Raymond, 1924; Euptychaspis Ulrich in Bridge, 1931; and Macronoda Lochman, 1964. At least four species are new, of which E. lawsonensis and M. notchpeakensis are named formally. Much previous work on Late Cambrian trilobites has emphasized biostratigraphic utility and the recognition of geographically widespread species. Data from new silicified collections indicate that this approach is difficult to justify because many putative ‘index species’ actually represent a plexus of closely related species whose biostratigraphic significance has yet to be determined. One such plexus is represented by E. kirki Kobayashi, 1935, whose previously reported occurrences in Texas, Oklahoma, Utah, Nevada and northern Canada record at least four distinct species. Similarly, Macronoda can now be shown to consist of at least five late Sunwaptan species in south-central and western North America.

Hierarchical competition in pond-breeding anuran larvae in a Mediterranean area

2007 ◽  
Vol 28 (2) ◽  
pp. 247-261 ◽  
Author(s):  
Alex Richter-Boix ◽  
Gustavo Llorente ◽  
Albert Montori
Keyword(s):  
Body Size ◽  
Competitive Ability ◽  
Niche Overlap ◽  
Distinct Species ◽  
Mediterranean Area ◽  
Activity Level ◽  
Temporary Ponds ◽  
Activity Levels ◽  
Anuran Larvae ◽  
Ephemeral Ponds

AbstractThe anuran larval guild is frequently characterised by the co-occurrence, with high niche overlap, of distinct species in the same pond at variables densities during development. Anuran larvae have therefore been widely studied as a model system for competition. Body size and activity level are considered the most important factors that influence the outcome of competition between tadpoles. As species from temporary ponds normally show higher activity levels in order to achieve rapid growth and thus reduce the risk of desiccation, these species are often considered superior competitors. We designed several laboratory experiments to examine the intra- and interspecific effects on growth rate, mass at metamorphosis and survival to metamorphosis of six species in a Mediterranean area. Body size and activity level were used as explanatory covariables to determine competitive ability among species. An asymmetric and hierarchical relationship was found among the six species. Larger tadpole species were more successful in competitive interactions than smaller ones, but no relationship was found between activity level and competition effects. Species typically found in temporary ponds (Pelodytes punctatus and Bufo calamita) were considered poor competitors in contrast with other communities studied. Species with low competitive ability can persist by using refuges in which competition is reduced (e.g. ephemeral ponds).

The specific identity of the algal symbiont in Convoluta roscoffensis

1967 ◽  
Vol 47 (2) ◽  
pp. 445-464 ◽  
Author(s):  
Mary Parke ◽  
Irene Manton
Keyword(s):  
Water Samples ◽  
Distinct Species ◽  
Free Living ◽  
Algal Symbiont ◽  
New Information ◽  
Golgi System ◽  
Electron Microscopes ◽  
Convoluta Roscoffensis ◽  
Specific Identity

The algal symbiont of Convoluta roscoffensis (Graff) has been studied with the light and electron microscopes both in situ in worms collected from four localities on the coast of Brittany and in various forms of isolates in culture. The same organism has also been obtained from populations of free-living monads collected from sand and water samples adjacent to the Convoluta colonies. Its structure and behaviour in culture are described and illustrated. Platymonas convolutae sp.nov. is a very distinct species with a rough-surfaced theca and a pyrenoid with some new characters not previously recorded in other members of the group. Some new information on scale and theca production from the Golgi system has also been obtained.

Elevational size variation and two new species of torrent frogs from Peninsular Malaysia (Anura: Ranidae: Amolops Cope)

Zootaxa ◽  
2018 ◽  
Vol 4434 (2) ◽  
pp. 250 ◽  
Author(s):  
CHAN KIN ONN ◽  
ROBIN KURIAN ABRAHAM ◽  
JESSE L. GRISMER ◽  
L. LEE GRISMER
Keyword(s):  
New Species ◽  
Body Size ◽  
Size Variation ◽  
Distinct Species ◽  
Peninsular Malaysia ◽  
Strong Positive Correlation ◽  
Morphometric Characters ◽  
Diagnostic Characters ◽  
Two New Species ◽  
Additional Support

Previously, only one species of torrent frog (Amolops larutensis) was thought to occur throughout Peninsular Malaysia. However, genomic work has demonstrated that populations from eastern Peninsular Malaysia form two separate lineages that are genetically distinct from A. larutensis that is now restricted to the western half of Peninsular Malaysia. This study demonstrates that all three lineages can be morphologically distinguished from each other, thereby providing additional support for the recognition of the eastern lineages as two distinct species. These lineages are described herein as Amolops gerutu sp. nov. from the eastern states of Kelantan, Terengganu, and Pahang, and A. australis sp. nov. from the southern-most state of Johor. In general, these two new species form a clade that is sister to A. larutensis and can be readily distinguished from it by having: (1) considerably denser and more pronounced dorsal tubercles, and (2) the posterodorsal surface of thighs having dense, dark stippling as opposed to broad vermiculations. Although differences in other morphometric characters were detected, their utility as diagnostic characters should be applied with caution due to the large intraspecific variation that overlaps among different species in many of the characters we measured. As such, we advocate for the use of tuberculation and pattern of the posterodorsal portion of the thighs as primary diagnostic characters. These characters can readily distinguish A. larutensis from the two new species. To differentiate A. australis sp. nov. from A. gerutu sp. nov. and A. larutensis, body size can be a good diagnostic character as A. australis sp. nov. is significantly smaller in both males (mean = 31.04 ± 1.59 mm) and females (mean = 46.48 ± 3.2 mm). Additionally, we show a strong positive correlation between body size and elevation, with populations from montane forests (>900 m asl) being considerably larger than populations at lower elevations. 

Systematics of the Australo-Papuan tree frogs known as Litoria bicolor (Anura:Hylidae) in the Papuan region

2008 ◽  
Vol 56 (4) ◽  
pp. 257 ◽  
Author(s):  
J. I. Menzies ◽  
S. J. Richards ◽  
M. J. Tyler
Keyword(s):  
New Species ◽  
Body Size ◽  
Distinct Species ◽  
Northern Territory ◽  
Advertisement Call ◽  
Body Proportions ◽  
Advertisement Calls ◽  
Origin And Evolution ◽  
Call Structure ◽  
Tree Frogs

We examined differences in morphology and advertisement calls of a large sample of frogs from the Australo-Papuan Region that resemble Litoria bicolor, and compared them with examples of that species from Australia. Consistent differences in body size, body proportions, and advertisement call structure among populations demonstrate that at least seven distinct species occur in the Australo-Papuan region, and that only the population represented by the holotype from the Northern Territory of Australia is Litoria bicolor s.s. Herein we describe four new species from the Papuan Region and comment on the origin and evolution of the Papuan members of the Litoria bicolor complex in the region.

New taxonomic and ontogenetic data on oribatid mites of the genus Eutegaeus (Acari, Oribatida, Eutegaeidae)

2021 ◽  
Vol 26 (1) ◽  
pp. 272-288
Author(s):  
Sergey G. Ermilov
Keyword(s):  
New Species ◽  
Body Size ◽  
Body Length ◽  
National Park ◽  
Oribatid Mites ◽  
Generic Diagnosis ◽  
Medium Length ◽  
New Information ◽  
Two New Species ◽  
Long Rod

Two new species of the genus Eutegaeus (Oribatida, Eutegaeidae) are described based on specimens from moss in the Queulat National Park of Chile. Eutegaeus aysenensis sp. nov. (description based on the adult, larva, deuto- and tritonymph) is morphologically similar to that of Eutegaeus lagrecai in having long, flagellate interlamellar and notogastral setae and rod-like bothridial seta; it differs from the latter by having smaller body size and comparatively long bothridial seta, the lamella having anteromedial process, and by the absence of striate ornamentation on notogaster. Eutegaeus queulatensis sp. nov. (description based on the adult, proto- and tritonymph) is morphologically similar to that of Eutegaeus membraniger in having a triangular anteromedial lamellar process, long, rod-like bothridial seta, foveate lamella, and dorsal notogastral setae of medium length; it differs from the latter by having smaller body length, thickened notogastral setae, flagellate interlamellar setae, setiform lamellar setae, a tubercle on epimere III, and absence of an anterolateral tooth on the lamella. Based on new information, several characters in the generic diagnosis of Eutegaeus adults are modified or expanded, and a preliminary diagnosis for juveniles is presented. The larva of E. aysenensis sp. nov. is the first to be described for the genus. Nymphs of four species of Eutegaeus are compared.

A new species of the genus Gekko Laurenti (Squamata: Sauria: Gekkonidae) from Vietnam with remarks on G. japonicus (Schlegel)

Zootaxa ◽  
2010 ◽  
Vol 2329 (1) ◽  
pp. 56 ◽  
Author(s):  
HERBERT RÖSLER ◽  
TRUONG QUANG NGUYEN ◽  
KIEN VAN DOAN ◽  
CUC THU HO ◽  
TAO THIEN NGUYEN ◽  
...  
Keyword(s):  
New Species ◽  
Body Size ◽  
Northern Vietnam ◽  
New Information ◽  
Lao Cai ◽  
A New Species ◽  
Dorsal Tubercle

We describe a new species of the gekkonid genus Gekko from northern Vietnam on the basis of four specimens from Lang Son and Lao Cai provinces. Gekko canhi sp. n. is distinguished from the remaining congeners by the combination of the following characters: body size moderate (SVL < 100 mm); supralabials 12–14, infralabials 10–13; nares in contact with rostral, internasal single, nasals 3; interorbitals 47–50; dorsal tubercle rows 10–13; scales between mental and cloacal slit 205–229; midbody scales 164–170; subdigital lamellae below first toe 13–16, below fourth toe 14–17; extensive webbing between fingers and toes minimal; tibial tubercles present; precloacal pores 5; postcloacal tubercles 2–3; tail round, not thickened at base; caudal tubercles present; subcaudals enlarged. We also provide new information on the taxonomy and distribution of G. japonicus in Vietnam.

A new wide-headed Fanged Frog of the Limnonectes kuhlii group (Anura: Dicroglossidae) from western Borneo with a redescription of Rana conspicillata Günther, 1872

Zootaxa ◽  
2017 ◽  
Vol 4317 (2) ◽  
pp. 291 ◽  
Author(s):  
J. MAXIMILIAN DEHLING ◽  
D. MATTHIAS DEHLING
Keyword(s):  
New Species ◽  
Body Size ◽  
Genetic Information ◽  
Taxonomic Revision ◽  
Distinct Species ◽  
Morphological Characters ◽  
Head Size ◽  
Type Series

We re-examined the type series of Rana conspicillata Günther, 1872 from Matang in western Sarawak, Borneo and found it to consist of specimens of three distinct species that can be separated by qualitative morphological characters and morphometrics. We re-allocate one paralectotype to Limnonectes hikidai and another to a large-sized species from western Borneo that we describe as new. The new species is morphologically distinguished from all described species of the L. kuhlii group from the Sunda region by body size, extent of toe webbing, head size and odontoid shape. It differs genetically from all described species for which genetic information is available. In order to facilitate the further taxonomic revision of the L. kuhlii group on Borneo, we provide a detailed morphological redescription of the holotype of Rana conspicillata. 

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