Crocodilian Species Research Articles

A Simple PCR-RAPD is Method to Identification of Indian Crocodiles

We describe the development of PCR-RAPD method to detection of Indian crocodiles. According to CITES (Convention on International Trade in Endangered Species) of Wild Fauna and Flora and 1972 Indian Wildlife Protection Act, for conservation of crocodile species listed subject to illegal trade for three Indian crocodile species were selected for simple, rapid and reliable molecular method for identification of crocodile-based crime exhibits like bones, skin, etc. DNAbased identification of species using PCR-RAPD technique for an identification of all the three Indian crocodile species, Crocodylus porosus, Crocodylus palustris and Gavialis gangeticus is presented here. A 780 bp segment of cytochrome b gene was amplified using novel primer followed by RAPD method it has produced Indian crocodile species-specific pattern for identifying three Indian crocodile species separately, which fulfills the prerequisite for its forensic application, this technique will show useful in recognition of all three Indian crocodile species genetic identification assay for enforcement use and strengthen conservation efforts.

Alligators use resonance for communication

Once humans master verbal communication, we babble incessantly on any topic under the sun. But even animals that are equipped with less sophisticated communication systems depend on the same resonances that we skilfully shape with our vocal tracts for communication. Stephan Reber from the University of Vienna, Austria, explains that vibrations – produced when air is pushed past the vocal folds – force air trapped in the vocal tract to vibrate (resonate) and it is these resonances that shape bird song and human syllables. Animals also use the frequency of these resonances (how high or low the sound appears) to communicate their body size, with the frequency of a resonance honestly reflecting their size – although some species are known to exaggerate by deepening their resonances. However, no one knew whether reptiles, such as crocodiles and alligators, used resonances to communicate with others. ‘Anurans – frogs and toads – do not seem to use them’, explains Reber, who decided to find out whether modern day reptilian relatives of the dinosaurs, such as crocodiles and alligators, use resonance for communication.Unsure how to distinguish between the vibrations produced by the vocal folds and resonance vibrations produced by air in the rest of the vocal tract, Reber asked his thesis advisor – Tecumseh Fitch – for advice, and recalls Fitch's simple response: ‘Just put one in heliox’. Explaining that sounds travel much faster in heliox than in normal air, changing the frequency of vocal resonances and producing the Mickey Mouse sound effect that we make after inhaling helium, Reber realised that if the reptiles used resonances in vocal communication, inhaling the modified air should also shift the frequency of sounds produced by resonance. However, he also knew that immersing large alligators in heliox and getting them to serenade on demand would be easier said than done.Travelling to the St Augustine Alligator Farm Zoological Park, USA, home to all 23 species of crocodilians, Reber and Judith Janisch were fortunate to find a small Chinese alligator in isolation in a tank. ‘And when the big alligators in one of the other enclosures were bellowing, she always bellowed’, recalls Reber with a smile. Realising that he could convert her enclosure into a rudimentary sound box complete with heliox atmosphere and that the female would happily bellow on demand when played recordings of her own voice, Reber teamed up with the conservation centre's filtration expert, Mark Robertson, to adapt her holding tank. And when he recorded her bellowing grunts in normal air and heliox, Reber was delighted that the grunts sounded different in the heliox atmosphere.Returning to Austria, Reber then joined Takeshi Nishimura to begin scrutinising the baffling frequency spectra for evidence of shifted resonances. After months of painstaking analysis, he could clearly see that although the bellows sounded deeper in heliox, there were resonances that had shifted to higher frequencies: one increased from 400 to 800 Hz, while the second rose from 1600 to 3200 Hz. Now he could add members of the crocodilian order to the roll-call of animals that use air resonance for communication.Reber admits that he is pleased that these ancient animals produce calls that are shaped by vocal tract resonance and is keen to find out how body size affects the frequency of an animal's vocal resonances. He is also excited that this is another piece of compelling evidence that dinosaurs may also have used acoustic resonance to communicate size. ‘If you see it [resonance] in the last two groups [birds and crocodilians] that share a common ancestor with all extinct dinosaurs, we can infer that dinosaurs probably used formants [resonances] too for communication’, says Reber.

The Strawberry Bank Lagerstätte reveals insights into Early Jurassic life

The Strawberry Bank Lagerstätte provides a rich insight into Early Jurassic marine vertebrate life, revealing exquisite anatomical detail of marine reptiles and large pachycormid fishes thanks to exceptional preservation, and especially the uncrushed, 3D nature of the fossils. The site documents a fauna of Early Jurassic nektonic marine animals (five species of fishes, one species of marine crocodilian, two species of ichthyosaurs, cephalopods and crustaceans), but also over 20 species of insects. Unlike other fossil sites of similar age, the 3D preservation at Strawberry Bank provides unique evidence on palatal and braincase structures in the fishes and reptiles. The age of the site is important, documenting a marine ecosystem during recovery from the end-Triassic mass extinction, but also exactly coincident with the height of the Toarcian Oceanic Anoxic Event, a further time of turmoil in evolution.

Similarity of Crocodilian and Avian Lungs Indicates Unidirectional Flow Is Ancestral for Archosaurs

Patterns of airflow and pulmonary anatomy were studied in the American alligator (Alligator mississippiensis), the black caiman (Melanosuchus niger), the spectacled caiman (Caiman crocodilus), the dwarf crocodile (Osteolaemus tetraspis), the saltwater crocodile (Crocodylus porosus), the Nile crocodile (Crocodylus niloticus), and Morelet's crocodile (Crocodylus moreletii). In addition, anatomy was studied in the Orinoco crocodile (Crocodylus intermedius). Airflow was measured using heated thermistor flow meters and visualized by endoscopy during insufflation of aerosolized propolene glycol and glycerol. Computed tomography and gross dissection were used to visualize the anatomy. In all species studied a bird-like pattern of unidirectional flow was present, in which air flowed caudad in the cervical ventral bronchus and its branches during both lung inflation and deflation and craniad in dorsobronchi and their branches. Tubular pathways connected the secondary bronchi to each other and allowed air to flow from the dorsobronchi into the ventrobronchi. No evidence for anatomical valves was found, suggesting that aerodynamic valves cause the unidirectional flow. In vivo data from the American alligator showed that unidirectional flow is present during periods of breath-holding (apnea) and is powered by the beating heart, suggesting that this pattern of flow harnesses the heart as a pump for air. Unidirectional flow may also facilitate washout of stale gases from the lung, reducing the cost of breathing, respiratory evaporative water loss, heat loss through the heat of vaporization, and facilitating crypsis. The similarity in structure and function of the bird lung with pulmonary anatomy of this broad range of crocodilian species indicates that a similar morphology and pattern of unidirectional flow were present in the lungs of the common ancestor of crocodilians and birds. These data suggest a paradigm shift is needed in our understanding of the evolution of this character. Although conventional wisdom is that unidirectional flow is important for the high activity and basal metabolic rates for which birds are renowned, the widespread occurrence of this pattern of flow in crocodilians indicates otherwise. Furthermore, these results show that air sacs are not requisite for unidirectional flow, and therefore raise questions about the function of avian air sacs.

The Biology and Conservation Status of the American Crocodile in Colombia

Abstract Along with the Orinoco and Cuban Crocodiles (Crocodylus intermedius and Crocodylus rhombifer), the American Crocodile (Crocodylus acutus) is among the most threatened crocodylian species in the Americas. Although this species is distributed widely, its IUCN “threat category” in several countries is “of concern.” We review the literature dealing with the biology and conservation status of C. acutus in Colombia and assess its Extent of Occurrence (EoO) and its EoO-Habitat Status. We propose a way to estimate the effective area of optimal habitable occurrence on the basis of the EoO (EoO-Effective Habitable Area). We found that only 37% of the national territories have been sampled in ecological studies during the last decade. The relatively few reports of abundance values and the lack of long-term projects that can produce accurate estimates of population sizes make it difficult to establish the conservation status of this species in Colombia. Our analyses indicate that the EoO-Habitat Status has a...

A Miocene hyperdiverse crocodylian community reveals peculiar trophic dynamics in proto-Amazonian mega-wetlands.

Amazonia contains one of the world's richest biotas, but origins of this diversity remain obscure. Onset of the Amazon River drainage at approximately 10.5 Ma represented a major shift in Neotropical ecosystems, and proto-Amazonian biotas just prior to this pivotal episode are integral to understanding origins of Amazonian biodiversity, yet vertebrate fossil evidence is extraordinarily rare. Two new species-rich bonebeds from late Middle Miocene proto-Amazonian deposits of northeastern Peru document the same hyperdiverse assemblage of seven co-occurring crocodylian species. Besides the large-bodied Purussaurus and Mourasuchus, all other crocodylians are new taxa, including a stem caiman-Gnatusuchus pebasensis-bearing a massive shovel-shaped mandible, procumbent anterior and globular posterior teeth, and a mammal-like diastema. This unusual species is an extreme exemplar of a radiation of small caimans with crushing dentitions recording peculiar feeding strategies correlated with a peak in proto-Amazonian molluscan diversity and abundance. These faunas evolved within dysoxic marshes and swamps of the long-lived Pebas Mega-Wetland System and declined with inception of the transcontinental Amazon drainage, favouring diversification of longirostrine crocodylians and more modern generalist-feeding caimans. The rise and demise of distinctive, highly productive aquatic ecosystems substantially influenced evolution of Amazonian biodiversity hotspots of crocodylians and other organisms throughout the Neogene.

Red Fire Ant (Solenopsis invicta) Effects on Broad-Snouted Caiman (Caiman latirostris) Nest Success

Abstract Flooding and predation are the two major causes for the decline in hatching rate and hatchling survival in crocodilian species. Recently, Solenopsis invicta (Red Fire Ant) has been recognized as a formidable invasive species, causing changes in wild populations of reptiles. Because of the elevated densities of Red Fire Ants present in Caiman latirostris (Broad-Snouted Caiman) nests during the breeding season, experiments in captivity and in the wild were performed to verify if the presence of S. invicta affects nest success or care of eggs and the hatching-assistance behavior of C. latirostris females. Hatchling survival from eggs incubated in a lab setting in the presence of Red Fire Ants decreased by approximately 10% compared to nests without ants. In a second experiment performed in the wild, the presence of Red Fire Ant resulted in a 43% reduction in nest success including direct (14.5%) and indirect (28.5%) effects. Our study confirmed that Red Fire Ants negatively affect C. latirostris nes...

Tooth counts through growth in diapsid reptiles: implications for interpreting individual and size-related variation in the fossil record.

Tooth counts are commonly recorded in fossil diapsid reptiles and have been used for taxonomic and phylogenetic purposes under the assumption that differences in the number of teeth are largely explained by interspecific variation. Although phylogeny is almost certainly one of the greatest factors influencing tooth count, the relative role of intraspecific variation is difficult, and often impossible, to test in the fossil record given the sample sizes available to palaeontologists and, as such, is best investigated using extant models. Intraspecific variation (largely manifested as size-related or ontogenetic variation) in tooth counts has been examined in extant squamates (lizards and snakes) but is poorly understood in archosaurs (crocodylians and dinosaurs). Here, we document tooth count variation in two species of extant crocodylians (Alligator mississippiensis and Crocodylus porosus) as well as a large varanid lizard (Varanus komodoensis). We test the hypothesis that variation in tooth count is driven primarily by growth and thus predict significant correlations between tooth count and size, as well as differences in the frequency of deviation from the modal tooth count in the premaxilla, maxilla, and dentary. In addition to tooth counts, we also document tooth allometry in each species and compare these results with tooth count change through growth. Results reveal no correlation of tooth count with size in any element of any species examined here, with the exception of the premaxilla of C.porosus, which shows the loss of one tooth position. Based on the taxa examined here, we reject the hypothesis, as it is evident that variation in tooth count is not always significantly correlated with growth. However, growth trajectories of smaller reptilian taxa show increases in tooth counts and, although current samples are small, suggest potential correlates between tooth count trajectories and adult size. Nevertheless, interspecific variation in growth patterns underscores the importance of considering and understanding growth when constructing taxonomic and phylogenetic characters, in particular for fossil taxa where ontogenetic patterns are difficult to reconstruct.

Surveys of endogenous retroviruses (ERVs) in the freshwater crocodile (Crocodylus johnstoni) suggest that ERVs in Crocodylus spp. vary between species.

Endogenous retroviruses (ERVs) are one of many families of transposable elements present in vertebrate genomes. We have examined the ERV complement of the freshwater crocodile (Crocodylus johnstoni) in order to investigate the diversity of ERVs present and possibility of ERV or retroviral activity in a diseased individual of this species. Amplification and sequencing of the highly conserved retroviral pro-pol domains revealed high levels of sequence variation in these ERVs. Phylogenetic analyses of these ERVs and those previously identified in other crocodilian species suggest that although many crocodilians share the same ERV lineages, the relative numbers of retroelement insertions from each of these lineages may vary greatly between species. The data generated in this study provide evidence for the presence of a unique and varied complement of ERVs in crocodilians. This study has also demonstrated the presence of species-specific evolution in ancient retroviral infections.

Role of Chromosome Changes in Crocodylus Evolution and Diversity.

The karyotypes of most species of crocodilians were studied using conventional and molecular cytogenetics. These provided an important contribution of chromosomal rearrangements for the evolutionary processes of Crocodylia and Sauropsida (birds and reptiles). The karyotypic features of crocodilians contain small diploid chromosome numbers (30~42), with little interspecific variation of the chromosome arm number (fundamental number) among crocodiles (56~60). This suggested that centric fusion and/or fission events occurred in the lineage, leading to crocodilian evolution and diversity. The chromosome numbers of Alligator, Caiman, Melanosuchus, Paleosuchus, Gavialis, Tomistoma, Mecistops, and Osteolaemus were stable within each genus, whereas those of Crocodylus (crocodylians) varied within the taxa. This agreed with molecular phylogeny that suggested a highly recent radiation of Crocodylus species. Karyotype analysis also suggests the direction of molecular phylogenetic placement among Crocodylus species and their migration from the Indo-Pacific to Africa and The New World. Crocodylus species originated from an ancestor in the Indo-Pacific around 9~16 million years ago (MYA) in the mid-Miocene, with a rapid radiation and dispersion into Africa 8~12 MYA. This was followed by a trans-Atlantic dispersion to the New World between 4~8 MYA in the Pliocene. The chromosomes provided a better understanding of crocodilian evolution and diversity, which will be useful for further study of the genome evolution in Crocodylia.

The Crocodile Museum at Zoológico Regional Miguel Álvarez del Toro (ZooMAT), Mexico: ‘How to exhibit a bullfrog’ put into reality

Staff at the Zoológico Regional Miguel Álvarez del Toro (ZooMAT), Mexico, have acquired over several decades extensive background knowledge about various aspects of the biology and conservation of the three species of crocodilians inhabiting Chiapas; the Chiapas' caiman Caiman crocodilus chiapasius, American crocodile Crocodylus acutus and Morelet's crocodile Crocodylus moreletii. This knowledge was put into practice when designing a new exhibit to provide visitors with a better understanding of crocodilians. In 2003, an initiative by the government of Chiapas State to support ZooMAT with new projects and renovations, resulted in the adaptation of an unfinished building, originally constructed as an aquarium, into a Crocodile Museum, which opened in 2004. The public enters via the open jaws of a scale model of an American crocodile, and inside visitors can view graphics and displays describing the natural history and ecology of the three species in a national and international context. Murals, dioramas with mounted animals, aqua–terrariums with living crocodiles and caimans, tanks containing animals that are part of the crocodilian food chain and the skeletons of specimens of diverse sizes are all on display. Outside the building there is a contact area where guides talk to the public and provide information, and visitors are allowed to touch materials laid out on a table. There is also an amphitheatre where formal lectures are given and visitors can view the enclosures containing breeding crocodilians. From here the visitors are able to access the remaining living collection of ZooMAT.

Articular soft tissue anatomy of the archosaur hip joint: Structural homology and functional implications.

Archosaurs evolved a wide diversity of locomotor postures, body sizes, and hip joint morphologies. The two extant archosaurs clades (birds and crocodylians) possess highly divergent hip joint morphologies, and the homologies and functions of their articular soft tissues, such as ligaments, cartilage, and tendons, are poorly understood. Reconstructing joint anatomy and function of extinct vertebrates is critical to understanding their posture, locomotor behavior, ecology, and evolution. However, the lack of soft tissues in fossil taxa makes accurate inferences of joint function difficult. Here, we describe the soft tissue anatomies and their osteological correlates in the hip joint of archosaurs and their sauropsid outgroups, and infer structural homology across the extant taxa. A comparative sample of 35 species of birds, crocodylians, lepidosaurs, and turtles ranging from hatchling to skeletally mature adult were studied using dissection, imaging, and histology. Birds and crocodylians possess topologically and histologically consistent articular soft tissues in their hip joints. Epiphyseal cartilages, fibrocartilages, and ligaments leave consistent osteological correlates. The archosaur acetabulum possesses distinct labrum and antitrochanter structures on the supraacetabulum. The ligamentum capitis femoris consists of distinct pubic- and ischial attachments, and is homologous with the ventral capsular ligament of lepidosaurs. The proximal femur has a hyaline cartilage core attached to the metaphysis via a fibrocartilaginous sleeve. This study provides new insight into soft tissue structures and their osteological correlates (e.g., the antitrochanter, the fovea capitis, and the metaphyseal collar) in the archosaur hip joint. The topological arrangement of fibro- and hyaline cartilage may provide mechanical support for the chondroepiphysis. The osteological correlates identified here will inform systematic and functional analyses of archosaur hindlimb evolution and provide the anatomical foundation for biomechanical investigations of joint tissues.

Redescription and molecular characterisation of Dujardinascaris madagascariensis and a note on D. dujardini (Nematoda: Heterocheilidae), parasites of Crocodylus niloticus, with a key to Dujardinascaris spp. in crocodilians.

An examination of one specimen of Nile crocodile, Crocodylus niloticus (Laurenti, 1768), from Lake Turkana (Kenya), revealed the presence of two ascaridoid nematodes belonging to the genus Dujardinascaris Baylis, 1947. Dujardinascaris madagascariensis Chabaud & Caballero, 1966 was studied by scanning electron microscopy, redescribed, and differentiated from D. dujardini (Travassos, 1920). Dujardinascaris madagascariencsis is the second of the genus to be sequenced. An internal fragment of the small ribosomal subunit and nuclear ribosomal DNA internal transcribed spacer 2 region were amplified--the slowly evolving 18S gene region was used for phylogenetic analysis. Molecular data confirmed affinity of D. madagascariensis to the family Heterocheilidae and revealed its closest relationship with D. waltoni. A key to the species of Dujardinascaris parasitizing crocodiles is provided.

Conservation of the Philippine crocodileCrocodylus mindorensis(Schmidt 1935):in situandex situmeasures

The endemic Philippine crocodile Crocodylus mindorensis is one of the most Critically Endangered crocodilian species in the world. Four major captive-breeding programmes for the Philippine crocodile have greatly contributed to our knowledge about the biology and natural history of the species. In situ conservation actions, such as reintroduction, conservation breeding in large semi-wild areas with no supplementary feeding and head-starting programmes, could result in increasing the numbers of extant wild and semi-wild populations. If concerted efforts are directed at in situ and ex situ conservation, and locating quality habitats in which to establish new conservation sites for Philippine crocodiles, the species is likely to become widespread in the next few decades. Conservation measures that address species-specific issues promoting healthy viable populations in natural habitats are presented in this paper.

Characterizing Tissue Enzyme Activities in the American Alligator (Alligator mississippiensis)

American alligators, Alligator mississippiensis, are one of 23 crocodilian species in the world, and they are common in the southeastern United States. Biochemical enzyme blood reference values have been established for the American alligator and several other crocodilians, but the tissue of origin of these enzymes has not been established. This study evaluated tissue specificity of six different enzymes in the American alligator, including alkaline phosphatase (ALP), alanine aminotransferase (ALT), aspartate aminotransferase (AST), lactate dehydrogenase (LDH), creatine kinase (CK), and gamma-glutamyl transferase (GGT). Six different tissues (liver, cardiac muscle, lung, kidney, skeletal muscle, and mid–small intestine) were collected from six subadult American alligators for enzyme analysis. The results showed that the CK and LDH enzymes were primarily derived from skeletal and cardiac muscle; ALT was derived primarily from kidney and skeletal muscle tissue; and AST was derived primarily from liver and skeletal muscle tissue. GGT and ALP appear to be of little diagnostic value regarding the tissues sampled because there was no statistical difference between the tissue levels. The results of this study should be of use to clinicians when interpreting biochemistry enzyme levels from blood samples.

Evolution and gene capture in ancient endogenous retroviruses - insights from the crocodilian genomes.

BackgroundCrocodilians are thought to be hosts to a diverse and divergent complement of endogenous retroviruses (ERVs) but a comprehensive investigation is yet to be performed. The recent sequencing of three crocodilian genomes provides an opportunity for a more detailed and accurate representation of the ERV diversity that is present in these species. Here we investigate the diversity, distribution and evolution of ERVs from the genomes of three key crocodilian species, and outline the key processes driving crocodilian ERV proliferation and evolution.ResultsERVs and ERV related sequences make up less than 2% of crocodilian genomes. We recovered and described 45 ERV groups within the three crocodilian genomes, many of which are species specific. We have also revealed a new class of ERV, ERV4, which appears to be common to crocodilians and turtles, and currently has no characterised exogenous counterpart. For the first time, we formally describe the characteristics of this ERV class and its classification relative to other recognised ERV and retroviral classes. This class shares some sequence similarity and sequence characteristics with ERV3, although it is phylogenetically distinct from the other ERV classes. We have also identified two instances of gene capture by crocodilian ERVs, one of which, the capture of a host KIT-ligand mRNA has occurred without the loss of an ERV domain.ConclusionsThis study indicates that crocodilian ERVs comprise a wide variety of lineages, many of which appear to reflect ancient infections. In particular, ERV4 appears to have a limited host range, with current data suggesting that it is confined to crocodilians and some lineages of turtles. Also of interest are two ERV groups that demonstrate evidence of host gene capture. This study provides a framework to facilitate further studies into non-mammalian vertebrates and highlights the need for further studies into such species.Electronic supplementary materialThe online version of this article (doi:10.1186/s12977-014-0071-2) contains supplementary material, which is available to authorized users.

Genetic barcoding facilitates captive and wild management of three cryptic African crocodile species complexes

AbstractManagement of threatened species with conserved morphology is hindered by misidentification and potential hybridization in captivity. African crocodiles of the genera Osteolaemus, Crocodylus and Mecistops were previously considered monotypic, but have recently been identified as consisting of three, two and two cryptic species, respectively. Mitochondrial cytochrome c oxidase subunit I (COI) new and published sequences from 310 wild‐caught specimens were compared with 71 US zoological specimens to identify (barcode) species. We also sequenced either nuclear lactate dehydrogenase A or an anonymous microsatellite flanking sequence in both wild and captive specimens to identify potential first‐generation intra‐generic hybridization in captive populations. The Osteolaemus COI barcoding gap was 7–9% sequence divergence. In contrast, the two African Crocodylus species had a 4.7% barcoding gap. These results, in addition to a previously published Mecistops barcoding gap (4.9%), support the use of barcoding as a tool for diagnosing African crocodile species in captive populations. Captive individuals from 14 collections in the US represented five of the seven putative African taxa. Nuclear heterozygosity at fixed polymorphisms differentiating species within genera suggested that 23% of the captive Osteolaemus samples were admixed O. tetraspis × O. sp. nov. cf. tetraspis – West Africa, while no ex situ hybrids were found for Crocodylus or Mecistops. Our results underscore the need to formally recognize divergent crocodile taxa, especially in light of regional threats, and for proper captive breeding management.

First observations on the courtship, mating, and nest visit behaviour of the Philippine crocodile (Crocodylus mindorensis) at the Cologne Zoo

The aim of this study was to gain a better understanding of the social and in particular reproductive behaviour of the Critically Endangered Philippine crocodile. Crocodylus mindorensis has been a focus for international conservation breeding measures for about two decades. Since little scientific data have been gathered on the biology and ecology of the species so far, its breeding remains a challenge. In order to identify behavioural patterns that trigger courtship behaviour, and to determine when sociopositive interactions increase and the animals are ready for reproduction, a pair of two adult C. mindorensis at Cologne Zoo was systematically observed between August 2011 and July 2012 for a total of 583 hours. Observations took place using all occurrences recording and scan sampling, focusing on pre-, post- and actual mating behaviour. We present a detailed documentation of copulations with behaviours such as growling, roaring, and bubbling. Bubbling in both sexes was observed prior to copulations and decreased with the end of the mating season, supporting the assumption that it can be referred to as courtship behaviour. Behaviours that indicate the approach of the breeding season, such as approaches to the dividing slide, bubbling and nest building, could be distinguished. Our findings should help to improve breeding efforts under captive husbandry conditions and thus contribute to the conservation breeding of this highly endangered and difficult to keep crocodilian species.

Preliminary report on the intestinal parasites and their diversity in captive Chinese alligators.

Although intestinal parasites are commonly detected in either wild or farmed crocodiles in other parts of the world, yet few reports have ever been on the captive bred Chinese alligators (Alligator sinensis) since they are only distributed in the southern areas of the Yangtze River. The current work was undertaken to investigate the intestinal parasites and their diversity in the Chinese crocodilian species. In May and October of 2013, we randomly collected a total of 328 fecal samples of the captive Chinese alligators in a breeding centre in south Anhui province. Three genera of protozoa (Entaoeba, Eimeria and Isospora), five genera of nematodes (Ascaris, Dujardinascaris, Capillaria, Toxocara and Strongylus), two genera of trematodes (Echinostoma and Clonorchis) and two families of trematodes (Schistosomatidae and Cryptogonimidae) were identified, in which Dujardinascaris was the most prevalent and led to the highest infection rate (14.33%), and Entaoeba ranked the second (13.11%). The number of species, richness index, diversity index and evenness index were higher in July and August, and those indexes were relatively most in juvenile and subadult alligators. Our findings suggest that the intestinal parasites infection was prevalent in captive Chinese alligators, and this condition requires our attention, whatever it is for controlling or preventing the intestinal parasitic disease from spreading to humans or conservation of this endangered species.

Are Seeds Consumed by Crocodilians Viable? A Test of the Crocodilian Saurochory Hypothesis

Many animal species are important dispersers of seeds; however, relatively little attention has been paid to the seed-dispersal capabilities of reptiles, and almost nothing is known about the seed-dispersal capabilities of crocodilians. This lack of information is surprising given that seeds have been found in the stomach contents of a majority of crocodilian species. Here we present the first experimental investigation of the seed-dispersal potential of a crocodilian. Using a comparative germination experiment, we tested the viability of Annona glabra (Pond-apple Tree) seeds recovered from the stomach of an Alligator mississippiensis (American Alligator [Alligator]) captured in the Florida Coastal Everglades. We found that seeds from the Alligator's stomach were nonviable under ideal germination conditions and that fresh, non-digested Pond-apple seeds exposed to the same germination conditions were highly viable. The seeds recovered from the Alligator’s stomach were nonviable because they were likely destroyed by stomach acids. Thus, Alligators are likely not dispersers of Pond-apple seeds and may instead act as seed predators. Further research is needed to test the potential of crocodilians as dispersers of other types of seeds from different plant families.