Folivory and seasonal changes in diet in Rana hexadactyla (Anura: Ranidae)

The autecology of Rana hexadactyla (Lesson) was studied at a seasonal locality in south India. The herbivorous larva transforms into an insectivorous frog, and a second dietary switch from insectivory to folivory occurs in adults, with plants constituting 79.5% of the diet, by volume. A variety of invertebrates and small vertebrates is consumed, especially by the adult females before the reproductive season. Larger frogs take larger animal prey and more prey types. Monthly figures of prey diversity generally show high values during the wet months.
In Rana hexadactyla , the utilization of permanent waterbodies may help buffer the impact of the long dry seasons and, together with a supply of abundant food in the form of aquatic macrophytes, is thought to be linked to the capacity of the species to spawn three times a year.     

Dentition of a mesolithic population from Wadi Halfa, Sudan

The dentition of a Mesolithic population (8,000–11,000 years old) from Wadi Halfa, Sudan, can be characterized as morphologically complex, massive and relatively free from pathology except that associated with extreme wear. Maxillary incisors show shoveling. All of the maxillary molars show some development of the hypocone. Supernumerary cusps appear frequently. Almost one-half of the second lower molars observed show distally located third cusps. Over one-half of the maxillary third molars show an extra cusp. A high percentage of mandibular molars show six cusps. Overall the teeth from this population compare favorably in size with those of an Australian aborigine tribe and are slightly larger than the teeth of the Neanderthaloids from Skūhl. The teeth show wear of a degree greater than that found in present day Eskimo or Australian aborigine groups. This data may be interpreted as indicating that this Mesolithic group was subjected to rigorous selective pressures favoring large and/or morphologically complex teeth. This pressure was apparently intensive wear, presumably caused by the inclusion of large amounts of grit in the diet through the eating of vegetable food macerated on coarse grinding stones.     

Testing microstructural adaptation in the earliest dental tools

Conodont elements are the earliest vertebrate dental structures. The dental tools on elements responsible for food fracture—cusps and denticles—are usually composed of lamellar crown tissue (a putative enamel homologue) and the enigmatic tissue known as ‘white matter’. White matter is unique to conodonts and has been hypothesized to be a functional adaptation for the use of elements as teeth. We test this quantitatively using finite-element analysis. Our results indicate that white matter allowed cusps and denticles to withstand greater tensile stresses than do cusps comprised solely of lamellar crown tissue. Microstructural variation is demonstrably associated with dietary and loading differences in teeth, so secondary loss of white matter through conodont phylogeny may reflect changes in diet and element occlusal kinematics. The presence, development and distribution of white matter could thus provide constraints on function in the first vertebrate dental structures.     

Characteristics of dentition in gekkonid lizards of the genus <Emphasis Type="Italic">Teratoscincus</Emphasis> and other Gekkota (Sauria,Reptilia)

The dentition and tooth crown microstructure of gekkonids and eublepharids are examined. Scanning electron microscopy shows that the lingual surface of teeth in these lizards has one, two, or, occasionally, several cusps separated by grooves. The teeth of geckoes usually have two (lingual and labial) cusps in the apical region. With respect to the number of teeth, the majority of Gekkota fall into two groups. The first includes a few species with many teeth (50 or more) in the dentary and maxilla, the eublepharids Goniurosaurus and Aeluroscalabotes, and the gekkonid Cyrtopodion louisiadensis. The second group, comprising most of the species, is subdivided into two subgroups, species with 20–30 or 30–40 teeth in jaw bones. Teratoscincus belongs to the first subgroup of the second group.     

Genetic diversity in mitochondrial 12S rDNA of western Palearctic water frogs (Anura, Ranidae) and implications for their systematics

The nucleotide sequence of a part of the mitochondrial 12S rRNA gene of eight western Palearctic water frog species was analysed. The results are consistent with the species status of Rana bedriagae, Rana bergeri, Rana epeirotica, Rana lessonae, Rana perezi, Rana ridibunda, Rana saharica and Rana shqiperica . The obtained DNA data suggest that lake frogs from Greece and Yugoslavia on the one hand and lake frogs from Georgia, Uzbekistan and Turkmenistan on the other hand represent two distinct species. However, it is not yet clear whether lake frogs from Georgia, Uzbekistan and Turkmenistan belong to R. ridibunda or represent a new species. The very high similarity between the analysed 12S rDNA segments of German R. ridibunda and R. lessonae confirm the finding that mtDNA of R. lessonae was transmitted into the mitochondrial gene pool of R. ridibunda probably as a result of backcrosses with the hybridogenetic hybrid R. kl. esculenta . The results of parsimony analyses speak in favour of very close phylogenetic relations between R. perezi and R. saharica ; with a high probability these species represent an adelphotaxon. Furthermore, the clades ( R. lessonae + R. shqiperica + R. bergeri ) and ( R. ridibunda + R. bedriagae ) are considered to be sister groups. According to the mt 12S rDNA data R. epeirotica seems to be more closely related to the supraspecific taxon ( R. ridibunda + R. bedriagae ) than to ( R. lessonae + R. shqiperica + R. bergeri ). Thus, it can be excluded that R. shqiperica and R. epeirotica represent sister species.     

Dietary adaptations in the teeth of murine rodents (Muridae): a test of biomechanical predictions

Functional dental theory predicts that tooth shape responds evolutionarily to the mechanical properties of food. Most studies of mammalian teeth have focused on qualitative measures of dental anatomy and have not formally tested how the functional components of teeth adapt in response to diet. Here we generated a series of predictions for tooth morphology based on biomechanical models of food processing. We used murine rodents (Old World rats and mice) to test these predictions for the relationship between diet and morphology and to identify a suite of functional dental characteristics that best predict diets. One hundred and five dental characteristics were extracted from images of the upper and lower tooth rows and incisors for 98 species. After accounting for phylogenetic relationships, we showed that species evolving plant‐dominated diets evolved deeper incisors, longer third molars, longer molar crests, blunter posteriorly angled cusps, and more expanded laterally oriented occlusal cusps than species adapting to animal‐dominated diets. Measures of incisor depth, crest length, cusp angle and sharpness, occlusal cusp orientation, and the lengths of third molars proved the best predictors of dietary adaptation. Accounting for evolutionary history in a phylogenetic discriminant function analysis notably improved the classification accuracy. Molar morphology is strongly correlated with diet and we suggest that these dental traits can be used to infer diet with good accuracy for both extinct and extant murine species.     

山东省的长肢林蛙种组物种

前人报道天津和山东有日本林蛙的分布,但也有学者表示怀疑。本文报道采集于山东徂徕山的该类物种。从成体量度和蝌蚪唇踟式来看,与现报道的镇海林蛙和峨眉林蛙有一定差异。该物种体型大小与峨眉林蛙相近似,唇齿式为1：2-2／111     

A new species of Rhinopetitia Géry 1964 (Ostariophysi: Characiformes: Characidae) from the Rio Teles Pires,Rio Tapajós basin,Brazil

A new species of Rhinopetitia is described from the Rio Teles Pires, a major tributary of the Rio Tapajós. The new taxon is distinguished from its only congener, Rhinopetitia myersi, by having all premaxillary teeth in both rows with seven to nine cusps, maxillary teeth with seven or eight cusps, a distinct dark midlateral stripe on the body and a round humeral blotch (v. outer series of premaxillary teeth with three cusps and inner series of premaxillary teeth with three to five cusps, maxillary teeth with three to five cusps, the absence of a dark midlateral stripe and humeral blotch). Putative characters suggesting a close relationship between Rhinopetitia, Bryconacidnus, Ceratobranchia, Monotocheirodon, Odontostoechus, Othonocheirodus and Rhinobrycon are presented. This putative clade is included in the Stevardiinae, a monophyletic group within the Characidae.     

The Microstructure,Proteomics and Crystallization of the Limpet Teeth

Limpets are marine mollusks that use mineralized teeth, one of the hardest and strongest biomaterials, to feed on algae on intertidal rocks. However, most of studies only focus on the ultrastructure and chemical composition of the teeth while the molecular information is largely unknown, limiting our understanding of this unique and fundamental biomineralization process. The study investigates the microstructure, proteomics, and crystallization in the teeth of limpet Cellana toreuma. It is found that the limpets formed alternatively tricuspid teeth and unicuspid teeth. Small nanoneedles are densely packed at the tips or leading regions of the cusps. In contrast, big nanoneedles resembling chemically synthesized goethite are loosely packed in the trailing regions of the cusps. Proteins extracted from the whole radula, such as ferritin, peroxiredoxin, arginine kinase, GTPase‐Rabs, and clathrin, are identified by proteomics. A goethite‐binding experiment coupled with proteomics and RNA‐seq highlights six chitin‐binding proteins (CtCBPs). Furthermore, the extracted proteins from the cusps of radula or the framework chitin induce packing of crystals and possibly affect crystal polymorphs in vitro. This study provides insight into the unique biomineralization process in the limpet teeth at the molecular levels, which may guide biomimetic strategies aimed at designing hard materials at room temperature.     

Evidence for chromosome number reduction and chromosomal homosequentiality in the 24-chromosome Korean frog Rana dybowskii and related species

The karyotype of the Korean frog Rana dybowskii with its pattern of C-band heterochromatin distribution was numerically analyzed. There are 2n = 24 chromosomes in the karyotype representing a reduction in number from the typical 2n = 26 chromosome karyotype of Rana. The karyotype shows other evidence of reorganization relative to 26-chromosome species. The chromosomes grade smoothly in size from largest to smallest without the two size classes that are characteristic for 26-chromosome species. In contrast to many 26-chromosome species, there are few centromeric C-bands but many interstitial ones. C-bands for each homologous chromosome pair are distinctive. A prominent secondary constriction is located on one of the smallest chromosomes, chromosome 11, in a position similar to that seen in most 26-chromosome species. The karyotype of R. dybowskii is compared to those of other species of Rana known to have 2n = 24 chromosomes; it is most similar to that of R. chensinensis, less so that of R. ornativentris and less still to that of R. arvalis in terms of the positions of centromeres and secondary constrictions. C-bands as well as secondary constrictions in the karyotypes of these frogs show evidence of chromosomal homosequentiality. The process and possible consequences of chromosome number reduction from an ancestral 26-chromosome karyotype is also evident in the karyotypes of these closely allied palearctic frogs. Pericentric inversions followed by fusion of two small elements apparently produced a new chromosome, chromosome 6, occurring originally among northeast Asian populations.     

AMP-deaminase activity in denervation atrophy of the amphibian skeletal muscle

The substrate (AMP) and co-factor (ATP)-dependent kinetic parameters of AMP-deaminase have been studied in the contralateral and denervated gastrocnemius muscles of frog, Rana hexadactyla. An increasing in apparent affinity (Km) and maximal velocity (V) were found with denervated muscle enzyme as compared to the contralateral muscle enzyme. The activation energy (delta E) values were found to be decreased on denervation suggesting increased catalytic efficiency of denervated muscle enzyme.     

Diet and dentition in tropical ariid catfishes from Australia

Synopsis The diets of 13 species of ariid catfishes from the tropical waters of the Gulf of Carpentaria are described and compared. Fishes were collected from two estuaries and inshore and offshore marine areas. Up to 10 species have been recorded from a single estuary. Although all are carnivorous and consume a variety of prey, diet analyses and statistical ordination reveal three feeding guilds - piscivores, polychaete-eaters and molluscivores. The diets of most species are similar between sites. There are strong relationships between dietary guild and the size and arrangement of the palatine teeth. The piscivorous group of catfish (guild 1) have large mouths with relatively large multiple palatine tooth plates, either in a band or in a triangular pattern and armed with sharp recurved teeth. The primarily polychaete-feeding group (guild 2) have a variable mouth size but it is usually smaller than that of guild 1 fish; their palatine teeth plates are fewer and smaller, and they have small, sharp recurved teeth. Guild 3 eat mainly molluscs, and have a small mouth and large posteriorly situated palatine plates with globular, truncated teeth. Overlaps in diet between species are probably reduced by differential distribution patterns within estuaries and different habitat preferences. The mouth-width and tooth-plate arrangements of ariids in tropical Australia are suitable for dealing with broad classes of prey rather than specific items, conferring dietary flexibility. This probably optimizes the trade-off for most species between occupation of broad feeding niches and the ability to shift diet easily.     

Primary teeth in Anura are nonpedicellate and bladed

1. Scanning electron microscop of the dentition of four anuran species (Discoglossus pictus, Bombina orientalis, Rana cyanophlyctis, Rana temporaria) revealed that at least the primary teeth, which are established during metamorphosis, are more or less bicuspid, bladed and nonpedicel-late. Juveniles and adults, however, have pedicellate teeth. 2. Thus, regardin the pedicellate condition, the sequence of stages in tooth development of Anura und Urodela show some similarities, although the primary teeth of urodeles develop already before metamorphosis.     

Functional morphology of comminuting feeding structures of Trichodactylus borellianus (Brachyura,Decapoda, Trichodactylidae), an omnivorous freshwater crab

Crustaceans exhibit great diversity of feeding structures with morphological traits that are useful to infer the general trophic habits of species. In this study, we analyzed the functional morphology of comminuting feeding structures (mandibles, chelipeds, gastric mill) of the freshwater crab Trichodactylus borellianus directly related with the food fragmentation. The heterochely and mechanical advantage (MA) of the chelae were also studied. In both analyses, we considered the relationship between morphology and the natural diet. We expected to find a consistent relation between feeding habits and morphological traits. In general, we found simple structures armed with uniform setal systems and feeding appendages without pronounced teeth or spines. Mandibles have primarily cutting functions, helping with the food anchoring and fragmentation with mandibular palps armed with pappose setae. Chelipeds were covered with spines and simple setae. Adult males exhibited right-handedness with high MA of the major chelae. The ingested, relatively large pieces of food are finally chewed by a gastric mill equipped with sharp cusps characteristic of decapods with low ingestion of crude fiber material. The morphology of the feeding apparatus revealed that it is well adapted to an omnivorous diet, being able to cope with dietary changes.     

The Effect of Assortative Mating on the Coexistence of a Hybridogenetic Waterfrog and Its Sexual Host

In central Europe, the hybridogenetic waterfrog Rana esculenta, a hybrid between Rana ridibunda and Rana lessonae, lives in sympatry with one of its parental species, the poolfrog Rana lessonae. As R. esculenta has to backcross constantly with R. lessonae in order to produce viable offspring, this coexistence is obligatory for R. esculenta. Since R. esculenta has a higher primary fitness than R. lessonae, a mechanism is required that prevents the hybrid from driving the parental species, and hence itself, to extinction. Here, we present an analytical model and a computer simulation that investigate whether assortative mating can operate as a such a control mechanism. Our results show that assortative mating is very effective in regulating coexistence in such a hybrid-host system. This is particularly true when choice is affected by the proportion of the two male types in the population. Furthermore, we could show that even if the species composition in a mixed hybrid-host population may be largely influenced by differences in life-history parameters, assortative mating still plays a very important role by stabilizing coexistence. Thus, mating behavior turns out to be more important for the populations dynamics of hybridogenetic waterfrog systems than previously assumed.     

Freezing tolerance of the European water frogs: the good, the bad, and the ugly

Survival and some physiological responses to freezing were investigated in three European water frogs (Rana lessonae, Rana ridibunda, and their hybridogen Rana esculenta). The three species exhibited different survival times during freezing (from 10 h for R. lessonae to 20 h for R. ridibunda). The time courses of percent water frozen were similar; however, because of the huge differences in body mass among species (from 10 g for Rana lessonae to nearly 100 g for Rana ridibunda), the ice mass accumulation rate varied markedly (from 0.75 +/- 0.12 to 1.43 +/- 0.11 g ice/h, respectively) and was lowest in the terrestrial hibernator Rana lessonae. The hybrid Rana esculenta exhibited an intermediate response between the two parental species; furthermore, within-species correlation existed between body mass and ice mass accumulation rates, suggesting the occurrence of subpopulations in this species (0.84 +/- 0.08 g ice/h for small R. esculenta and 1.78 +/- 0.09 g ice/h for large ones). Biochemical analyses showed accumulation of blood glucose and lactate, liver glucose (originating from glycogen), and liver alanine in Rana lessonae and Rana esculenta but not in Rana ridibunda in response to freezing. The variation of freeze tolerance between these three closely related species could bring understanding to the physiological processes involved in the evolution of freeze tolerance in vertebrates.     

Peptidomic analysis of skin secretions from Rana heckscheri and Rana okaloosae provides insight into phylogenetic relationships among frogs of the Aquarana species group

The members of the Aquarana (or Rana catesbeiana species group) form a monophyletic group comprising seven species: R. catesbeiana, Rana clamitans, Rana grylio, Rana virgatipes, Rana septentrionalis, Rana heckscheri and Rana okaloosae. Previous work has led to structural characterization of the antimicrobial peptides present in electrically-stimulated skin secretions from the first five species listed and this study presents the primary structures of orthologs from the river frog R. heckscheri and the Florida bog frog R. okaloosae. Peptidomic analysis of R. heckscheri and R. okaloosae skin secretions led to the identification of peptides with antimicrobial activity belonging to the ranalexin, ranatuerin-2, and temporin families. In addition, a peptide (GFLDIIKDTGKDFAVKILNNLKCKLAGGCPR) was isolated from R. okaloosae whose primary structure identified it as a member of the palustrin-2 family. Consistent with previous data based upon morphological analysis and comparisons of the nucleotide sequences of mitochondrial and ribosomal genes, cladistic analysis based upon a comparison of the amino acid sequences of antimicrobial peptides indicates a sister-group relationship between R. heckscheri and R. grylio and a close, but less well defined, phylogenetic relationship between R. okaloosae and R. clamitans.     

Reiterative signaling and patterning during mammalian tooth morphogenesis

Mammalian dentition consists of teeth that develop as discrete organs. From anterior to posterior, the dentition is divided into regions of incisor, canine, premolar and molar tooth types. Particularly teeth in the molar region are very diverse in shape. The development of individual teeth involves epithelial-mesenchymal interactions that are mediated by signals shared with other organs. Parts of the molecular details of signaling networks have been established, particularly in the signal families BMP, FGF, Hh and Wnt, mostly by the analysis of gene expression and signaling responses in knockout mice with arrested tooth development. Recent evidence suggests that largely the same signaling cascade is used reiteratively throughout tooth development. The successional determination of tooth region, tooth type, tooth crown base and individual cusps involves signals that regulate tissue growth and differentiation. Tooth type appears to be determined by epithelial signals and to involve differential activation of homeobox genes in the mesenchyme. This differential signaling could have allowed the evolutionary divergence of tooth shapes among the four tooth types. The advancing tooth morphogenesis is punctuated by transient signaling centers in the epithelium corresponding to the initiation of tooth buds, tooth crowns and individual cusps. The latter two signaling centers, the primary enamel knot and the secondary enamel knot, have been well characterized and are thought to direct the differential growth and subsequent folding of the dental epithelium. Several members of the FGF signal family have been implicated in the control of cell proliferation around the non-dividing enamel knots. Spatiotemporal induction of the secondary enamel knots determines the cusp patterns of individual teeth and is likely to involve repeated activation and inhibition of signaling as suggested for patterning of other epithelial organs.     

A new species of leopard frog (Anura: Ranidae) from the urban northeastern US

Past confusion about leopard frog (genus Rana) species composition in the Tri-State area of the US that includes New York (NY), New Jersey (NJ), and Connecticut (CT) has hindered conservation and management efforts, especially where populations are declining or imperiled. We use nuclear and mitochondrial genetic data to clarify the identification and distribution of leopard frog species in this region. We focus on four problematic frog populations of uncertain species affiliation in northern NJ, southeastern mainland NY, and Staten Island to test the following hypotheses: (1) they are conspecific with Rana sphenocephala or R. pipiens, (2) they are hybrids between R. sphenocephala and R. pipiens, or (3) they represent one or more previously undescribed cryptic taxa. Bayesian phylogenetic and cluster analyses revealed that the four unknown populations collectively form a novel genetic lineage, which represents a previously undescribed cryptic leopard frog species, Rana sp. nov. Statistical support for R. sp. nov. was strong in both the Bayesian (pp=1.0) and maximum-likelihood (bootstrap=99) phylogenetic analyses as well as the Structure cluster analyses. While our data support recognition of R. sp. nov. as a novel species, we recommend further study including fine-scaled sampling and ecological, behavioral, call, and morphological analyses before it is formally described.     

Tooth replacement in the frog Rana temporaria

The development and replacement of teeth in the frog Rana temporaria is analyzed by dividing the life cycle of the tooth into a number of stages. These stages are identified by the examination of alizarin whole mounts. The dentition in this species is fairly complete and the percentage of functional loci is approximately 74. The teeth in alternate loci are usually at about the same stage in development. The low percentage of non-functional loci is accounted for by the retention of functional teeth over a large fraction of the total life cycle time and the relatively rapid ankylosis of replacement teeth. It is suggested that tooth replacement is essentially a process which involves teeth in alternate loci and that the replacement waves (which connect alternate loci) run parallel to the longitudinal axis of the jaw and are of infinite length. This basic pattern is obscured by many breaks which occur in the replacement waves. The presence of such breaks may be accounted for by variations in the time intervals between the successive stimuli which initiate the Zahnreihen, or simply by the acceleration or deceleration of the development of teeth in one or more loci.