A new study of the brain of the predatory dinosaur <Emphasis Type="Italic">Tarbosaurus bataar</Emphasis> (Theropoda,Tyrannosauridae)

The brain morphology and the topography of the cranial nerves on an endocranial mold of the theropod dinosaur Tarbosaurus bataar (Tyrannosauridae) are examined. The brain of this dinosaur was constructed based on the reptile archetype, with a well-developed specialized olfactory analyzer. In terms of development, the visual centers were superseded not only by the olfactory centers, but also by the auditory centers. Comparative analysis of the brain structure of Tarbosaurus and Tyrannosaurus shows clear distinctions in the topography of roots of the accessory and trigeminal nerves.     

Year-long presence of Eimeria echidnae and absence of Eimeria tachyglossi in captive short-beaked echidnas ( Tachyglossus aculeatus )

The short-beaked echidna ( Tachyglossus aculeatus ) is 1 of 5 extant species of monotreme, found only in Australia and Papua New Guinea. The aim of this study was to identify the species of coccidia present and establish a range of subclinical Eimeria spp. (Coccidia: Apicomplexa) oocyst shedding in echidnas from eastern Australia over 18 mo. The coccidia were detected in 89% (49/55) of fecal samples from 12 long-term monitored and healthy captive echidnas, 75% (3/4) of 4 healthy long-term captive echidnas, 83% (5/6) of 6 short-term captive echidnas, and 60% (6/10) of 10 wild echidnas. Echidnas captive for 4 to 23 yr shed 100-46,000 oocysts g(-1) of E. echidnae and remained clinically healthy during this study. Sub-adult and adult wild, and short-term captive, echidnas shed oocysts of both E. echidnae and E. tachyglossi . The lack of coccidia in juvenile short-beaked echidnas suggests these animals are probably non-immune and should not be placed in environments heavily contaminated with oocysts. In addition, no oocysts were found in captive long-beaked echidnas ( Zaglossus bartoni bartoni , n = 2) housed at Taronga Zoo. This study represents an important step in understanding the host-parasite interaction between coccidia and short-beaked echidnas.     

Passive electroreception in aquatic mammals

Passive electroreception is a sensory modality in many aquatic vertebrates, predominantly fishes. Using passive electroreception, the animal can detect and analyze electric fields in its environment. Most electric fields in the environment are of biogenic origin, often produced by prey items. These electric fields can be relatively strong and can be a highly valuable source of information for a predator, as underlined by the fact that electroreception has evolved multiple times independently. The only mammals that possess electroreception are the platypus (Ornithorhynchus anatinus) and the echidnas (Tachyglossidae) from the monotreme order, and, recently discovered, the Guiana dolphin (Sotalia guianensis) from the cetacean order. Here we review the morphology, function and origin of the electroreceptors in the two aquatic species, the platypus and the Guiana dolphin. The morphology shows certain similarities, also similar to ampullary electroreceptors in fishes, that provide cues for the search for electroreceptors in more vertebrate and invertebrate species. The function of these organs appears to be very similar. Both species search for prey animals in low-visibility conditions or while digging in the substrate, and sensory thresholds are within one order of magnitude. The electroreceptors in both species are innervated by the trigeminal nerve. The origin of the accessory structures, however, is completely different; electroreceptors in the platypus have developed from skin glands, in the Guiana dolphin, from the vibrissal system.     

Body temperature in captive long-beaked echidnas (Zaglossus bartoni)

The routine occurrence of both short-term (daily) and long-term torpor (hibernation) in short-beaked echidnas, but not platypus, raises questions about the third monotreme genus, New Guinea's Zaglossus. We measured body temperatures (T(b)) with implanted data loggers over three and a half years in two captive Zaglossus bartoni at Taronga Zoo, Sydney. The modal T(b) of both long-beaks was 31 degrees C, similar to non-hibernating short-beaked echidnas, Tachyglossus aculeatus, in the wild (30-32 degrees C) and to platypus (32 degrees C), suggesting that this is characteristic of normothermic monotremes. T(b) cycled daily, usually over 2-4 degrees C. There were some departures from this pattern to suggest periods of inactivity but nothing to indicate the occurrence of long-term torpor. In contrast, two short-beaked echidnas monitored concurrently in the same pen showed extended periods of low T(b) in the cooler months (hibernation) and short periods of torpor at any time of the year, as they do in the wild. Whether torpor or hibernation occurs in Zaglossus in the wild or in juveniles remains unknown. However, given that the environment in this study was conducive to hibernation in short-beaks, which do not easily enter torpor in captivity, and their large size, we think that torpor in wild adult Zaglossus is unlikely.     

The influence of habitat accessibility on the dietary and morphological specialisation of an aquatic predator

Individual diet and habitat specialisation are widespread in animal taxa and often related to levels of predation and competition. Mobile consumers such as predatory fish can stabilise lake food webs by ranging over a larger area than their prey, thereby switching between habitats. Although, this switching assumes that the predator has equal preference for the available prey, individual diet specialisation and morphological adaptations to different habitats could potentially prevent individuals from switching between habitats. In this study, we assessed the niche width and individual specialisation in Eurasian perch Perca fluviatilis in response to a shift in habitat use by manipulating the ability for this top predator to couple habitats. We ran an eight weeks pond experiment, to test the effect of habitat switching on diet and morphological specialisations. We show that habitat coupling influenced individual diet specialisation and niche use in expected directions where specialisation increased with decreasing habitat switching. In contrast to expectations, the morphological variation decreased with increasing diet specialisation. Our results expand on previous work and suggest that individual specialisation and niche width can impact the ability of mobile predators to couple habitats. Furthermore, it shows the importance of individual specialisations in relation to habitat coupling.     

Spatial and temporal segregation of auditory and vestibular neurons in the otic placode

The otic placode generates the auditory and vestibular sense organs and their afferent neurons; however, how auditory and vestibular fates are specified is unknown. We have generated a fate map of the otic placode and show that precursors for vestibular and auditory cells are regionally segregated in the otic epithelium. The anterior-lateral portion of the otic placode generates vestibular neurons, whereas the posterior-medial region gives rise to auditory neurons. Precursors for vestibular and auditory sense organs show the same distribution. Thus, different regions of the otic placode correspond to particular sense organs and their innervating neurons. Neurons from contiguous domains rarely intermingle suggesting that the regional organisation of the otic placode dictates positional cues to otic neurons. But, in addition, vestibular and cochlear neurogenesis also follows a stereotyped temporal pattern. Precursors from the anterior-lateral otic placode delaminate earlier than those from its medial-posterior portion. The expression of the proneural genes NeuroM and NeuroD reflects the sequence of neuroblast formation and differentiation. Both genes are transiently expressed in vestibular and then in cochlear neuroblasts, while differentiated neurons express Islet1, Tuj1 and TrkC, but not NeuroM or NeuroD. Together, our results indicate that the position of precursors within the otic placode confers identity to sensory organs and to the corresponding otic neurons. In addition, positional information is integrated with temporal cues that coordinate neurogenesis and sensory differentiation.     

Pleistocene and Holocene rhinocerotids (Mammalia,Perissodactyla) from the Indochinese Peninsula

Rhinocerotids were abundant and diverse in southern Asia during the Pleistocene and the Holocene epochs, as shown by palaeontological and archaeological discoveries published throughout the last century, whereas the only living rhinoceros in the Indochinese Peninsula is Rhinoceros sondaicus (Cat Loc Reserve, Vietnam). The Pleistocene-Holocene Indochinese rhinocerotid record consists of the extinct species Dicerorhinus gwebinensis (Early Pleistocene, Myanmar) and representatives of the Recent Asian Species Rhinoceros unicornis (Middle-Late Pleistocene), R. sondaicus (Middle Pleistocene-Recent), and Dicerorhinus sumatrensis (Middle Pleistocene-Holocene). This fossil record is synthesized, mapped for Early/Middle/Late Pleistocene and Holocene/Recent times, and then compared with coeval rhinocerotid assemblages from the adjacent areas (South China), subregions (Indian, Sundaic, Philippine, and Wallacean), and region (Palearctic), from a biochronological and biogeographical perspective.     

Implications of Diet for the Extinction of Saber-Toothed Cats and American Lions

The saber-toothed cat, Smilodon fatalis, and American lion, Panthera atrox, were among the largest terrestrial carnivores that lived during the Pleistocene, going extinct along with other megafauna ∼12,000 years ago. Previous work suggests that times were difficult at La Brea (California) during the late Pleistocene, as nearly all carnivores have greater incidences of tooth breakage (used to infer greater carcass utilization) compared to today. As Dental Microwear Texture Analysis (DMTA) can differentiate between levels of bone consumption in extant carnivores, we use DMTA to clarify the dietary niches of extinct carnivorans from La Brea. Specifically, we test the hypothesis that times were tough at La Brea with carnivorous taxa utilizing more of the carcasses. Our results show no evidence of bone crushing by P. atrox, with DMTA attributes most similar to the extant cheetah, Acinonyx jubatus, which actively avoids bone. In contrast, S. fatalis has DMTA attributes most similar to the African lion Panthera leo, implying that S. fatalis did not avoid bone to the extent previously suggested by SEM microwear data. DMTA characters most indicative of bone consumption (i.e., complexity and textural fill volume) suggest that carcass utilization by the extinct carnivorans was not necessarily more complete during the Pleistocene at La Brea; thus, times may not have been “tougher” than the present. Additionally, minor to no significant differences in DMTA attributes from older (∼30–35 Ka) to younger (∼11.5 Ka) deposits offer little evidence that declining prey resources were a primary cause of extinction for these large cats.     

A new large barn owl (Aves, Strigiformes, Tytonidae) from the Middle Pleistocene of Sicily, Italy, and its taphonomical significance

A new species of Tytonidae, Tyto mourerchauvireae, is described from the Sicilian cave deposits of Spinagallo, Luparello and Marasà, which have yielded a common vertebrate fossil assemblages referred to the early Middle Pleistocene. T. mourerchauvireae nov. sp. shows a pronounced increase in body size compared to other congeneric taxa. It is larger than the extant Tyto alba and the extinct Tyto balearica and Tyto sanctialbani and comparable in size among the Mediterranean taxa only with the extinct Tyto robusta, which differs in some morphological characteristics of the long bones. The insular adaptations of T. mourerchauvireae nov. sp. and the differences from the other forms of the genus Tyto which spread through the Mediterranean area during Neogene and Pleistocene are discussed. The fossil assemblages of the early Middle Pleistocene of Sicily are dominated by extinct giant Gliridae of the genus Leithia and Maltamys; these taxa are regarded as the primary prey items of T. mourerchauvireae nov. sp. The Gliridae remains were analysed microscopically to detect possible modifications of bones and teeth caused by ingestion and digestion processes. This type of analysis, together with the qualitative study of the fossil assemblages, allows to show the taphonomical importance of T. mourerchauvireae nov. sp. as agent of accumulation in such Sicilian fossil assemblages. Incidentally the taxonomic validity of T. robusta is discussed and confirmed.     

PHEV infection: A promising model of betacoronavirus-associated neurological and olfactory dysfunction

Porcine hemagglutinating encephalomyelitis virus (PHEV) is a highly neurotropic coronavirus belonging to the genus Betacoronavirus. Similar to pathogenic coronaviruses to which humans are susceptible, such as SARS-CoV-2, PHEV is transmitted primarily through respiratory droplets and close contact, entering the central nervous system (CNS) from the peripheral nerves at the site of initial infection. However, the neuroinvasion route of PHEV are poorly understood. Here, we found that BALB/c mice are susceptible to intranasal PHEV infection and showed distinct neurological manifestations. The behavioral study and histopathological examination revealed that PHEV attacks neurons in the CNS and causes significant smell and taste dysfunction in mice. By tracking neuroinvasion, we identified that PHEV invades the CNS via the olfactory nerve and trigeminal nerve located in the nasal cavity, and olfactory sensory neurons (OSNs) were susceptible to viral infection. Immunofluorescence staining and ultrastructural observations revealed that viral materials traveling along axons, suggesting axonal transport may engage in rapid viral transmission in the CNS. Moreover, viral replication in the olfactory system and CNS is associated with inflammatory and immune responses, tissue disorganization and dysfunction. Overall, we proposed that PHEV may serve as a potential prototype for elucidating the pathogenesis of coronavirus-associated neurological complications and olfactory and taste disorders.     

Revision of Late Pleistocene and Holocene Galliformes Fauna from the Crimean Mountains

The Late Pleistocene and Holocene Galliformes faunas from the Crimean Mountains included seven species of birds belonging to the families Phasianidae and Tetraonidae: Phasianus colchicus, Alectoris chukar, Perdix perdix, Coturnix coturnix, Lyrurus tetrix, Lagopus mutus, and Lagopus lagopus. The habitation of Gallus representatives in the Crimea in the Late Pleistocene has not been confirmed. Representatives of the family Phasianidae were present in the Crimean fauna at least for most of the Late Pleistocene. All of them survived until the Late Holocene. Pheasants became extinct around the eighteenth century, and the rock partridge seems to have disappeared only in the first half of the twentieth century. The species were restored in the Crimea in the second half of the twentieth century. Gray partridges were common resident birds of the Crimean Mountains throughout the Late Pleistocene and Holocene. Quail was not a numerous breeding species of the Crimean Mountains at the same time, but mass migration of this species through the Crimea appeared only at the end of the Late Pleistocene and evolved over the Holocene warming. Species of Tetraonidae appeared in the fauna of the Crimea long before the beginning of the cold-phase maximum of the last glaciations but no later than 28000 years ago and became extinct in the Early Holocene warming but no later than 9000 years ago.     

First discovery of colobine fossils from the early to middle Pleistocene of southern Taiwan

Here we report on two kinds of cercopithecid fossil monkeys (Cercopithecinae and Colobinae) from the early to middle Pleistocene sediments of the Chochen (=Tsochen) area (Tsailiao-chi or Shinhua Hill), southern Taiwan. The fossil specimens include the first fossil record of colobine monkeys from Taiwan, where only macaque monkeys now occur. All cercopithecine fossils were identified as Macaca cf. Macaca cyclopis, the extant Taiwan macaque, except for one extremely large isolated upper molar, which may belong to another macaque species. On the other hand, all colobine specimens fall within the size variation of extant and extinct Rhinopithecus, but its specific status cannot be determined because of the scantiness of the fossil material. In Taiwan, Rhinopithecus presumably became extinct in the late Pleistocene, probably owing to global cooling and vegetation change, whereas macaques, which are of almost the same body size as Rhinopithecus, survived as M. cyclopis to the present. The contrasting history of survival between the two kinds of monkeys may be due to ecological/behavioral differences between them or as a result of accidental events that occurred in the Pleistocene of Taiwan.     

Alternative egg-feeding tactics in <Emphasis Type="Italic">Telmatherina sarasinorum</Emphasis>, a trophic specialist of Lake Matano’s evolving sailfin silversides fish radiation

Feeding specialisation is a typical feature of adaptive animal radiations. Different kinds of feeding specialisations have evolved in the endemic sailfin silversides species flock in Lake Matano (Central Sulawesi, Indonesia), including egg-feeding. The present study focuses on Telmatherina sarasinorum, a sailfin silverside species feeding on the eggs of related Telmatherina antoniae. Stomach content analyses supported T. antoniae eggs to be the dominant food item, independent of daytime. We hypothesized that the egg-feeders use alternative tactics for maximising egg consumption under varying densities of both, spawning T. antoniae pairs and competing conspecific egg-feeders. Focal behavioural observations were applied to describe different feeding tactics and to analyse feeding success and the related costs in terms of competitive interactions. Egg-feeders followed single courting pairs of T. antoniae or, alternatively, they switched between different spawning pairs. Following-behaviour, covering one or more spawning events of the host species, was positively related to enhanced egg consumption. Compared to feeding by switching frequently among different spawning pairs, the following tactic came at the cost of likewise increased competition. Behavioural observations suggest that some males monopolize courting pairs of T. antoniae and gain increased amounts of eggs compared to others avoiding competition by switching among pairs. The present results confirm that egg-feeding is a distinct trophic specialisation in T. sarasinorum and increase the scale of behavioural specialisation in Lake Matano’s evolving Telmatherina radiation.     

Cerebral activation to intranasal chemosensory trigeminal stimulation

Although numerous functional magnetic resonance imaging (FMRI) studies have been performed on the processing of olfactory information, the intranasal trigeminal system so far has not received much attention. In the present study, we sought to delineate the neural correlates of trigeminal stimulation using carbon dioxide (CO(2)) presented to the left or right nostril. Fifteen right-handed men underwent FMRI using single runs of 3 conditions (CO(2) in the right and the left nostrils and an olfactory stimulant-phenyl ethyl alcohol-in the right nostril). As expected, olfactory activations were located in the orbitofrontal cortex (OFC), amygdala, and rostral insula. For trigeminal stimulation, activations were found in "trigeminal" and "olfactory" regions including the pre- and postcentral gyrus, the cerebellum, the ventrolateral thalamus, the insula, the contralateral piriform cortex, and the OFC. Left compared with right side stimulations resulted in stronger cerebellar and brain stem activations; right versus left stimulation resulted in stronger activations of the superior temporal sulcus and OFC. These results suggest a trigeminal processing system that taps into similar cortical regions and yet is separate from that of the olfactory system. The overlapping pattern of cortical activation for trigeminal and olfactory stimuli is assumed to be due to the intimate connections in the processing of information from the 2 major intranasal chemosensory systems.     

Complete Mitochondrial Genome and Phylogeny of Pleistocene MammothMammuthus primigenius

Phylogenetic relationships between the extinct woolly mammoth(Mammuthus primigenius), and the Asian(Elephas maximus) and African savanna(Loxodonta africana) elephants remain unresolved. Here, we report the sequence of the complete mitochondrial genome (16,842 base pairs) of a woolly mammoth extracted from permafrost-preserved remains from the Pleistocene epoch—the oldest mitochondrial genome sequence determined to date. We demonstrate that well-preserved mitochondrial genome fragments, as long as ~1,600–1700 base pairs, can be retrieved from pre-Holocene remains of an extinct species. Phylogenetic reconstruction of the Elephantinae clade suggests thatM. primigenius andE. maximus are sister species that diverged soon after their common ancestor split from theL. africana lineage. Low nucleotide diversity found between independently determined mitochondrial genomic sequences of woolly mammoths separated geographically and in time suggests that north-eastern Siberia was occupied by a relatively homogeneous population ofM. primigenius throughout the late Pleistocene.     

The distinction between the extinct Pleistocene European Crane,Grus primigenia,and the extant Asian Sarus Crane,G. antigone

In contradiction with the conclusions of some previousworkers, the extant Sarus Crane, Grus antigone (L.), and the extinct large Crane, Grus primigeniaMilne-Edwards, from the Pleistocene of Europe, cannot be considered as conspecific. In fact, the tibiotarsal epicondyles, particularly the medial epicondyle, the distal end of the humerus, its ventral epicondyle and the adjoining process, are comparatively smaller in Grus primigenia. These findings indicate differences in locomotion.     

Hair cells in the inner ear of the pirouette and shaker 2 mutant mice

The shaker 2 (sh2) and pirouette (pi) mouse mutants display severe inner ear dysfunction that involves both auditory and vestibular manifestation. Pathology of the stereocilia of hair cells has been found in both mutants. This study was designed to further our knowledge of the pathological characteristics of the inner ear sensory epithelia in both the sh2 and pi strains. Measurements of auditory brainstem responses indicated that both mutants were profoundly deaf. The morphological assays were specifically designed to characterize a pathological actin bundle that is found in both the inner hair cells and the vestibular hair cells in all five vestibular organs in these two mutants. Using light microscope analysis of phalloidin-stained specimens, these actin bundles could first be detected on postnatal day 3. As the cochleae matured, each inner hair cell and type I vestibular hair cell contained a bundle that spans from the region of the cuticular plate to the basal end of the cell, then extends along with cytoplasm and membrane, towards the basement membrane. Abnormal contact with the basement membrane was found in vestibular hair cells. Based on the shape of the cellular extension and the actin bundle that supports it, we propose to name these extensions “cytocauds.” The data suggest that the cytocauds in type I vestibular hair cells and inner hair cells are associated with a failure to differentiate and detach from the basement membrane.