From Clinging to Digging: The Postembryonic Skeletal Ontogeny of the Indian Purple Frog,Nasikabatrachus sahyadrensis (Anura: Nasikabatrachidae)

The Indian Purple frog, Nasikabatrachus sahyadrensis, occupies a basal phylogenetic position among neobatrachian anurans and has a very unusual life history. Tadpoles have a large ventral oral sucker, which they use to cling to rocks in torrents, whereas metamorphs possess adaptations for life underground. The developmental changes that underlie these shifts in habits and habitats, and especially the internal remodeling of the cranial and postcranial skeleton, are unknown. Using a nearly complete metamorphic series from free-living larva to metamorph, we describe the postembryonic skeletal ontogeny of this ancient and unique monotypic lineage. The torrent-dwelling larva possesses a dorsoventrally flattened body and a head with tiny dorsal eyes, robust lower and upper jaw cartilages, well-developed trabecular horns, and a definable gap between the trabecular horns and the tip of the snout. Unlike tadpoles of many other frogs, those of Nasikabatrachus retain larval mouthparts into late metamorphic stages. This unusual feature enables the larvae to maintain their clinging habit until near the end of metamorphosis. The subsequent ontogenetic shift from clinging to digging is correlated with rapid morphological changes and behavioral modifications. Metamorphs are equipped with a shortened tibiafibula and ossified prehallical elements, which likely facilitate initial digging using the hind limbs. Subsequently, the frogs may shift to headfirst burrowing by using the wedge-shaped skull, anteriorly positioned pectoral girdle, well-developed humeral crests and spatula-shaped forelimbs. The transition from an aquatic life in torrents to a terrestrial life underground entails dramatic changes in skeletal morphology and function that represent an extreme in metamorphic remodeling. Our analysis enhances the scope for detailed comparative studies across anurans, a group renowned for the diversity of its life history strategies.     

Genetic and morphological identification of Sebastiscus tertius in the East China Sea (Scorpaeniformes: Scorpaenidae)

The allozymes and morphology of 110 specimens of three Sebastiscus species (S. marmoratus, S. tertius, and S. albofasciatus) in the East China Sea and near Japan were compared. Results of 20 allozyme loci studied showed that all three species were closely related (Nei's unbiased genetic distances, 0.057–0.133) but could be identified on the basis of informative loci with a few exceptions. Initial identification based on color patterns agreed with allozyme identification in more than 98% of Sebastiscus specimens and agreed completely in S. albofasciatus. One specimen that was initially identified as S. marmoratus because of the dark body color was actually S. tertius according to two informative allozyme loci. Number of pectoral fin rays differed between S. marmoratus (18 or fewer, 98%) and S. tertius (19 or more, 85%) in this study. The previously mentioned dark specimen had 19 pectoral fin rays, which are characteristic in S. tertius. Using seven morphological measurements, canonical discriminant analysis between S. marmoratus and S. tertius classified less than 90% of specimens into the original groups (species). Some specimens of S. tertius resembled S. marmoratus in body shape and vice versa. A combination of genetic characterization and morphological examination is necessary to identify S. marmoratus and S. tertius accurately. Distinction based on allozymes and color patterns with numbers of pectoral fin rays should provide satisfactory identification. Received: May 16, 2000 / Revised: December 19, 2000 / Accepted: January 24, 2001     

Demographic dynamics of the afro-tropical pig-nosed frog, <Emphasis Type="Italic">Hemisus marmoratus</Emphasis>: effects of climate and predation on survival and recruitment

We studied the population ecology of the West African pig-nosed frog, Hemisus marmoratus, to understand the relative contributions of adult survival and recruitment to population growth rate in savannah frogs using mark-recapture modelling. We marked a total of 821 adult frogs over 6 years and recaptured 74 at least once between years. Between-year adult survival was sex-specific and varied between 0.06 and 0.53 for males and 0.07–0.41 for females. Adult survival was significantly associated with annual rainfall and is cause for concern if rainfall declines further in the study region as predicted by changes in the global climate. There was a significant interaction between rainfall and sex with dry weather having a stronger negative effect on males than females. Pig-nosed frogs experienced boom and bust years with a single decline more dramatic than increases. Recruitment (in situ and immigration; 0.67–0.88) was substantially more important than adult survival (0.12–0.33) in determining realised population growth. In situ recruitment was highly variable between years with 1–36% of eggs and tadpoles released by females into the pond surviving to metamorphosis. Years of low tadpole survival were associated with high numbers of predatory tortoises. Thus, like other pond-breeding anurans, pig-nosed frogs showed highly variable juvenile recruitment, low adult survival and density-independent effects on population growth by predators and weather.     

Intertidal distribution and species composition of brachyuran crabs at two rocky shores in Central Portugal

The objectives of the present study are to describe and compare the brachyuran community of rocky shores within the Central Portuguese coast and to examine the zonation patterns of the most representative species. For this, randomly placed transects were surveyed to obtain crab counts according to microhabitat and intertidal level. Repeated sampling in two different shores during two different seasons provided spatial and temporal replication for zonation analyses. Seven species were registered: Pachygrapsus marmoratus, Eriphia verrucosa, Xantho incisus, Carcinus maenas, Necora puber, Pirimela denticulata and Pilumnus hirtellus. Species density rankings are the same at both localities, but the less exposed shore presents higher diversity. While most species are mainly confined to specific microhabitats in the lower level, P. marmoratus and E. verrucosa can exploit the whole intertidal range. Regardless of shore and season, E. verrucosa is more abundant in the lower intertidal levels, while no such zonation patterns were recorded for P. marmoratus. Initial predictions concerning the effect of wave exposure and temperature on the zonation of those species are not validated after analysing the factorial model proposed. Between-shore contrasts were found instead, with higher densities recorded in the more exposed locality for both species. Possible causes of the observed patterns are discussed.     

The vocal sac of Hylodidae (Amphibia,Anura): Phylogenetic and functional implications of a unique morphology

Anuran vocal sacs are elastic chambers that recycle exhaled air during vocalizations and are present in males of most species of frogs. Most knowledge of the diversity of vocal sacs relates to external morphology; detailed information on internal anatomy is available for few groups of frogs. Frogs of the family Hylodidae, which is endemic to the Atlantic Forest of Brazil and adjacent Argentina and Paraguay, have three patterns of vocal sac morphology—that is, single, subgular; paired, lateral; and absent. The submandibular musculature and structure of the vocal sac mucosa (the internal wall of the vocal sac) of exemplar species of this family and relatives were studied. In contrast to previous accounts, we found that all species of Crossodactylus and Hylodes possess paired, lateral vocal sacs, with the internal mucosa of each sac being separate from the contralateral one. Unlike all other frogs for which data are available, the mucosa of the vocal sacs in these genera is not supported externally by the mm. intermandibularis and interhyoideus . Rather, the vocal sac mucosa projects through the musculature and is free in the submandibular lymphatic sac. The presence of paired, lateral vocal sacs, the internal separation of the sac mucosae, and their projection through the m. interhyoideus are synapomorphies of the family. Furthermore, the specific configuration of the m. interhyoideus allows asymmetric inflation of paired vocal sacs, a feature only reported in species of these diurnal, stream‐dwelling frogs.     

Developmental morphology of the cottid fish Pseudoblennius marmoratus

Embryonic, larval, and juvenile development of a Japanese cottid fish Pseudoblennius marmoratus is described from laboratory-reared specimens. Eggs of P. marmoratus resembled those of two congeners, Pseudoblennius cottoides and Pseudoblennius percoides, but differed in their smaller diameter and yolk color. Although the larvae and juveniles of P. marmoratus were also similar to them in general morphology, the former differed in the lengths of newly hatched larvae, pigmentation patterns, number of pectoral fin rays, and dorsal fin spine elongation.     

Burrowing mechanisms and sculptures in Recent gastropods

Savazzi, Enrico 1989 01 15: Burrowing mechanisms and sculptures in Recent gastropods. Lethaia , Vol. 22, pp. 31–48. Oslo. ISSN 0024–1164.
Burrowing was observed in 32 gastropod species, belonging to 8 families, from Italy and the Philippines. Most species burrow by repeating a three-phase sequence: (1) digging with the foot, (2) dragging the shell forward and downward, and (3) rocking the shell around its longitudinal axis. Minor specific differences in the burrowing dynamics are common, and totally different mechanisms also occur. Burrowing sculptures consisting of terraces or asymmetrical tubercles are observed in the majority of the studied species. Characteristics of the burrowing process explain some cases of apparent divergence of burrowing sculptures from the paradigm. Burrowing sculptures in the Gastropoda should be expected to occur mostly among medium-slender, rather than markedly high-spired, shell morphologies. □ Mollusca, Gastropoda, Cerithiidae, Nassariidae, Mitridae, Costellariidae, Conidae, Terebridae, Turridae, Hydro-biidae, shell, sculpture, burrowing, functional morphology, ecology, behaviour, Holocene, Indo-Pacific. Philippines, Mediterranean, Italy .     

Chromosome 1 in crested and marbled newts (Triturus)

The heteromorphic chromosomes 1 of Triturus cristatus carnifex and T. marmoratus were studied in mitotic metaphase after staining with the Giemsa C-banding technique and with the fluorochromes, DAPI (AT-specific) and mithramycin (GC-specific). They were also examined in the lampbrush form under phase-contrast before fixation and after fixation and staining with Giemsa. Chromosomes 1 of T.c. carnifex are asynaptic and achiasmatic throughout most of their long arms. They are also heteromorphic in most of their long arms for the patterns of Giemsa and fluorochrome staining and the distribution of distinctive lampbrush loops. The heteromorphic regions correspond to the regions that are asynaptic and achiasmatic. They stain more strongly with mithramycin and more weakly with DAPI than the remainder of the chromosomes, signifying that their DNA is relatively rich in GC. The patterns of staining with Giemsa and fluorochromes and the distributions of distinctive lateral loops vary from one animal to another in the same species and even in the same population. The asynaptic and achiasmatic regions of chromosomes 1 in T. marmoratus extend throughout the whole of the long arms and well beyond the heterochromatic region. Chiasmata form only in the short arm and occasionally in the short euchromatic segment at the tip of the long arms. The staining patterns of chromosomes 1 in T. marmoratus differ from those in T.c. carnifex although, like carnifex, their DNA is relatively GC-rich. The chromosomes 1 of T. marmoratus are more submetacentric than those of T.c. carnifex. In T. marmoratus chromosome 1B is about 12% shorter than 1A. There is a short paracentric inversion heterozygosity in the long arm of chromosome 1B in T. marmoratus which probably accounts for the lack of chiasmata in the euchromatin that separates the centromere from the start of the heterochromatin. In both carnifex and marmoratus, embryos that are homomorphic for chromosome 1 arrest and die at the late tailbud stage of development. The same applies to F₁ hybrid embryos T.c. carnifex x T. marmoratus, and this has permitted identification of chromosomes 1A and 1B in both species. There is no correspondence between patterns of Giemsa or fluorochrome staining of the heteromorphic regions of chromosome 1 and any feature of the lampbrush chromosomes. However, the short euchromatic ends of the long arms of chromosomes 1 in both species are distinguished in the lampbrush form by a series of uniformly small loops of fine texture associated with very small chromomeres. The Giemsa C-staining patterns of both chromosomes 1A and 1B are different in each of the four subspecies of T. cristatus. T.c. karelinii stands out by having unusually large masses of Giemsa C-staining centromeric heterochromatin on all but 1 of its 12 chromosomes. A scheme is proposed for the evolution of chromosome 1 in T. cristatus and T. marmoratus, based on all available cytological and molecular data.     

Can they dig it? Functional morphology and semifossoriality among small‐eared shrews,genus Cryptotis (Mammalia,Soricidae)

Small‐eared shrews (Mammalia: Soricidae: Cryptotis), exhibit modifications of the forelimb skeleton that have been interpreted as adaptations for semifossoriality. Most species inhabit remote regions, however, and their locomotory and foraging behaviors remain mostly speculative. To better understand the morphological modifications in the absence of direct observations, we quantified variation in these species by measuring 151 individuals representing 18 species and populations of Cryptotis and two species of moles (Talpidae) for comparison. From our measurements, we calculated 22 indices, most of which have been used previously to characterize substrate use among rodents and other taxa. We analyzed the indices using 1) average percentile ranks, 2) principal components analysis, and 3) cluster analysis. From these analyses, we determined that three basic modes of substrate adaptation are present within Cryptotis: 1) a primarily terrestrial mode, with species that are capable of burrowing, but lack adaptations to increase digging efficiency, 2) a semifossorial mode, with species whose forelimbs bones show strong muscle attachment areas and increased mechanical advantage, and 3) an intermediate mode. In addition to identifying new morphological characters and contributing to our understanding of the functional morphology of soricids, these analyses provide additional insight into the ecology of the species of interest. J. Morphol. 275:745–759, 2014. © 2014 Wiley Periodicals, Inc.     

Skeletal Morphology of Palaeocastor peninsulatus (Rodentia,Castoridae) from the Fort Logan Formation of Montana (early Arikareean): Ontogenetic and Paleoecological Interpretations

Palaeocastorine beavers were diverse members of the burrowing fauna of the Oligocene of North America best known from the Great Plains and the Great Basin. Palaeocastorines are also found in the northern Rocky Mountains. Several specimens of Capacikala, Euhapsis, and Palaeocastor have been reported from Montana within the Cabbage Patch beds fauna. New occurrences of palaeocastorine beavers from the Fort Logan Formation of central Montana show that the fauna there included Palaeocastor fossor, Capacikala sp., Palaeocastor sp., and three specimens of a species previously known only from the John Day Formation of Oregon: Palaeocastor peninsulatus. The three specimens include crania and associated postcrania forming an ontogenetic series from a juvenile to a mature adult. Careful examination of these specimens shows that morphological changes throughout ontogeny are associated with increased burrowing ability in adults. Palaeocastor peninsulatus is a scratch-digger with few cranial adaptations to burrowing susceptible to change with maturity. Dental characters, however, are modified with wear and vary greatly across individuals of similar wear stage. Cranial morphology thus appears to be a reliable source of taxonomic information in palaeocastorines unlike dental material. These new specimens provide evidence for increased chisel-tooth digging in adults compared to juveniles as is observed throughout the evolution of palaeocastorines. This study demonstrates the need for future work focusing on intraspecific variation to help better define species boundaries among palaeocastorines and improve phylogenetic analyses.     

Postnatal development of subterranean habits in tuco-tucos <Emphasis Type="Italic">Ctenomys talarum</Emphasis> (Rodentia,Caviomorpha, Ctenomyidae)

Postnatal development of subterranean habits was investigated in Los Talas’ tuco-tuco Ctenomys talarum, a subterranean caviomorph rodent endemic from South America. Since in this species, some key morpho-functional traits related to scratch-digging behaviour—a form of underground progression—are already present during early ontogeny and develop progressively, we predicted that this behaviour expresses early during postanatal development and its performance enhances gradually from pups to adults. The process of acquisition of different behaviours associated to the construction of a burrow system was recorded in 11 individuals, each one coming from different litters, inside a terrarium filled with natural soil. We found that scratch-digging and burrowing behaviours expressed early during postnatal development, particularly, during lactancy. The digging of a “true burrow” clearly preceded the dispersal age, with a high inter-individual variability, from 18 (lactancy) to 47 (post-weaning) postnatal days. Pups could lose the soil using their foreclaws and remove the accumulated substrate using their hindfeet as adults do. During lactancy individuals could construct a simple burrow to shelter, and first burrow construction occurred in the absence of either a burrowing demonstrator or an early subterranean environment (a natal burrow). However, certain features of the complex burrow system that characterize this species, such as lateral branches and nest chamber, just appeared after weaning. The time elapsed until animals started to dig and the time dedicated to underground activities varied with age, decreasing and increasing, respectively. In sum, our results show that—in C. talarum—immature digging behaviour gets expressed early during ontogeny, and develops progressively. The role of the early ability to build its own burrow and its possible function influencing the development of musculoskeletal traits and on efficiency for such conduct is discussed.     

Amphibian abundance and diversity in Meru National Park, Kenya

The diversity and abundance of amphibians were investigated in Meru National Park, Kenya, using transect sampling, drift‐fence and pitfall trapping and opportunistic collecting. A total of 430 individuals under seven genera (Amietophrynus, Hemisus, Hyperolius, Phrynobatrachus, Phrynomantis, Ptychadena, Xenopus) comprising eleven species were sampled in three different habitats (apart from this, two additional species are known from Meru National Park): Acacia‐wooded grassland; Combretum‐wooded grassland; Acacia–Commiphora bushland. The sex ratio for almost all species was balanced (chi‐square, χ²; P > 0.5) and was not affected by habitat type (ANOVA: F = 8.3026, P = 0.6914). Shannon–Weaver Index (2.227) and Simpson's Index (8.244) were relatively high, and most of the eleven species sampled appeared to have a relatively even distribution (Shannon's Evenness Index, E = 0.927). However, Hemisus marmoratus and Phrynomantis bifasciatus were exclusively recorded in Acacia‐wooded grassland and in low abundances. There was a positive linear relationship of body weight against snout–vent length for two randomly selected anurans (Hyperolius glandicolor, Phrynobatrachus natalensis) among all three vegetation communities.     

Toxic soles,Pardachirus marmoratus from the Red Sea and P. pavoninus from Japan,with notes on other species

Synopsis Fishes of the genus Pardachirus (Soleidae) are reviewed. Four species are recognized and their distribution mapped: P. marmoratus (Lacépède) from the Red Sea and Indian Ocean, P. pavoninus (Lapédè) and P. poropterus (Bleeker) from the Indo-Pacific, and P. hedleyi (Ogilby) from estuarine waters of Australia. Achirus rautheri Chabanaud is placed in synonymy with P. hedleyi. The ichthyocrinotoxic effect on teleosts of the secretion from P. pavoninus is described and compared with that of P. marmoratus. The distribution of poison glands in these two species shows more glands present on the eyed side. The number of glands range from 212 to 235 in P. marmoratus and 204 to 237 in P. pavoninus and number of rays on fins associated with the poison glands are about the same for both species. P. marmoratus appears to be more toxic than P. pavoninus.     

COMPACT DISC REVIEW

ABSTRACT

In previous studies, calling sites of two species of burrowing frogs Eupsophus in southern Chile have been shown to amplify conspecific vocalizations generated externally, thus providing a means to enhance the reception of neighbour's vocalizations in breeding aggregations. In the current study the amplification of vocalizations of Eusophus roseus was investigated to explore the extent of sound enhancement reported previously for two congeneric species. Advertisement calls broadcast through a loudspeaker placed in the vicinity of a burrow, monitored with small microphones, are amplified by up to 14 dB inside cavities relative to outside. The fundamental resonant frequency of burrows, measured with broadcast noise and pure tones, ranges from 345–1335 Hz; however it is not correlated with burrow length. The spectra of incoming calls are altered inside burrows by predominantly increasing the amplitude of lower relative to higher harmonics. The call amplification effect inside burrows of E. roseus parallels the effect reported previously for two congeneric species and reinforces the suggestion that sound enhancement inside calling sites has a widespread effect on signal reception by burrowing animals.     

The systematics and adaptations of some Papuan microhylid frogs which live underground

A taxonomic, anatomical and behavioural account is given of some burrowing microhylid frogs from New Guinea. Six species belonging to four genera are dealt with, of these four are described as new species. Two genera are removed from synonomy to accommodate four of the burrowing species. Histological and anatomical modifications to the head, which are associated with head-first burrowing, are described. The calls of the male frogs are described in detail and attention is drawn to the similarity of calls made by all burrowing species. This is discussed in relation to the problems of sound transmission below ground.     

One House Two Families: Petrel Squatters Get a Sniff of Low‐Cost Breeding Opportunities

Burrowing is a widespread nesting behaviour, found in vertebrates and invertebrates. It is particularly common in small procellariiform seabirds such as blue petrels (Halobaena caerulea) and Antarctic prions (Pachyptila desolata), two closely related petrel species. However, digging a burrow is costly and alternative strategies may evolve. Accordingly, blue petrel males can adopt two alternative nesting strategies: digging a new burrow or squatting in an empty one. Importantly, a blue petrel squatter arriving at the colony to breed is more likely to find empty Antarctic prion burrows than empty blue petrel burrows, since the former species only start breeding a month later. However, squatting in a prion’s burrow is risky for blue petrels as the legitimate owner very often returns and claims the burrow back, thus ruining the squatter’s breeding attempt. We present here results of a survey of two sympatric colonies of blue petrels and Antarctic prions on Kerguelen Island. Our data show that blue petrel squatters preferentially occupy blue petrel empty burrows. To investigate potential underlying mechanisms behind this preference, we used a simple Y‐maze design to show that blue petrels can discriminate and prefer their specific odour over the prion odour. Our results confirm the existence of alternative burrowing strategies in blue petrels and suggest that squatters could use olfaction to avoid the less suitable Antarctic prion burrows.     

Landscape genetics reveals unique and shared effects of urbanization for two sympatric pool‐breeding amphibians

Metapopulation‐structured species can be negatively affected when landscape fragmentation impairs connectivity. We investigated the effects of urbanization on genetic diversity and gene flow for two sympatric amphibian species, spotted salamanders (Ambystoma maculatum) and wood frogs (Lithobates sylvaticus), across a large (>35,000 km²) landscape in Maine, USA, containing numerous natural and anthropogenic gradients. Isolation‐by‐distance (IBD) patterns differed between the species. Spotted salamanders showed a linear and relatively high variance relationship between genetic and geographic distances (r = .057, p < .001), whereas wood frogs exhibited a strongly nonlinear and lower variance relationship (r = 0.429, p < .001). Scale dependence analysis of IBD found gene flow has its most predictable influence (strongest IBD correlations) at distances up to 9 km for spotted salamanders and up to 6 km for wood frogs. Estimated effective migration surfaces revealed contrasting patterns of high and low genetic diversity and gene flow between the two species. Population isolation, quantified as the mean IBD residuals for each population, was associated with local urbanization and less genetic diversity in both species. The influence of geographic proximity and urbanization on population connectivity was further supported by distance‐based redundancy analysis and multiple matrix regression with randomization. Resistance surface modeling found interpopulation connectivity to be influenced by developed land cover, light roads, interstates, and topography for both species, plus secondary roads and rivers for wood frogs. Our results highlight the influence of anthropogenic landscape features within the context of natural features and broad spatial genetic patterns, in turn supporting the premise that while urbanization significantly restricts interpopulation connectivity for wood frogs and spotted salamanders, specific landscape elements have unique effects on these two sympatric species.     

Water relations of the burrowing sandhill frog, Arenophryne rotunda (Myobatrachidae)

Arenophryne rotunda is a small (2–8 g) terrestrial frog that inhabits the coastal sand dunes of central Western Australia. While sand burrowing is a strategy employed by many frog species inhabiting Australia’s semi-arid and arid zones, A. rotunda is unique among burrowing species because it lives independently of free water and can be found nocturnally active on the dune surface for relatively extended periods. Consequently, we examined the physiological factors that enable this unique frog to maintain water balance. A. rotunda was not found to have any special adaptation to reduce EWL (being equivalent to a free water surface) or rehydrate from water (having the lowest rehydration rate measured for 15 Western Australian frog species), but it was able to maintain water balance in sand of very low moisture (1–2%). Frogs excavated in the field were in dune sand of 4.4% moisture content, as a consequence of recent rain, which was more than adequate for these frogs to maintain water balance as reflected by their low plasma and urine osmotic concentrations. We suggest that in dry periods of the year, A. rotunda can achieve positive water balance by cutaneous water uptake by burrowing deeper into the substrate to where the percent water content is greater than 1.5%.