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Background and Research Aims: The Urías Coastal Lagoon (UCL) is a heavily modified and polluted lagoon near Mazatlán, in northwestern Mexico. Once abundant in the UCL, the American crocodile (Crocodylus acutus) is now rarely seen in the area. A healthy population of apex predators is essential to maintain the trophic balance of ecosystems. Our research aim was to lay the groundwork for studies of American crocodile population ecology in the UCL. Methods: Traditional boat surveys (day and night) of crocodiles were undertaken in the UCL in May-July 2022. Two exploratory aerial (∼ 30 m altitude) surveys of a small wetland located close to a habitational complex in the vicinity of the UCL were performed in June and December 2022, using a commercial Unmanned Aerial Vehicle (UAV). We used images obtained with the UAV to estimate the size of the crocodiles detected in the wetland. Results: This study confirms the presence of American crocodiles in the UCL and presents the first information on individuals of this species for this area. Aerial surveys revealed the presence of 17 individuals in the wetland; the mean size of nine of those individuals was 183.3 ± 60 cm (range: 130-310 cm). Two yearlings (∼37 cm length), possibly born in June 2022, were captured in the same wetland in September 2022. We also surveyed 50.7 km of UCL coastline by boat, but no crocodiles were sighted. Conclusion: The crocodiles seem to avoid the human-impacted UCL and likely use the less impacted surrounding wetlands as a refuge area, which they also use to reproduce. The presence of both yearlings and adults is a good sign for the survival of this vulnerable population. Implications for Conservation: We believe that the surveyed wetland should be closely monitored for conservation purposes because it might be one of the last crocodile breeding refuges in the heavily modified and polluted coastal environment of the UCL. We summarize our results with a series of recommendations for local and federal authorities. These recommendations would likely help the conservation of the American crocodile population in the UCL. [ABSTRACT FROM AUTHOR]

Leptospiral agglutinins have been measured in several species of chelonians in studies dating back to the1960s. However, despite the fact that sea turtles are one of the most charismatic and endangered groups of chelonians, only a single study has measured leptospiral antibodies in this group. Serum samples collected from hawksbill sea turtles (Eretmochelys imbricata) (n = 10) and green sea turtles (Chelonia mydas) (n = 10) from two locations from the Gulf of Mexico were analyzed to detect Leptospira interrogans using the microagglutination test. Hawksbill and green sea turtles tested positive to five and seven serovars, respectively, with the serovars Grippotyphosa, Bratislava, and Canicola presenting a prevalence ≥50% in both species. Titers ranged from 1:50 to 1:400. These and previous results demonstrate that terrestrial, freshwater, and sea turtles are exposed to Leptospira at some stage of their life. The role of reptiles in the epidemiology, persistence, and transmission of leptospirosis is still controversial; however, there is evidence that some species of turtles can disseminate them in the environment. The detection of Leptospira is of sanitary importance as it is a cosmopolitan zoonotic disease. Preventive measures should be taken by people working in sea turtle camps and aquariums to control and reduce their risk of exposure. [ABSTRACT FROM AUTHOR]

A study which offered data on the diet of the Curly-tailed lizard Leiocephalus macropus and on the sexual dimorphism of the sub-species in the Guantanamo Province, Cuba is presented.

Crocodilians show universal parental care, but few studies concentrate on this behavior in wild crocodiles. We studied nest and hatchling care in genetically pure wild American crocodiles (Crocodylus acutus) on two Caribbean islands of Mexico. From 2006 to 2009 we made direct observations of crocodile behavior upon discovery of nests and groups of hatchlings in Banco Chinchorro. In 2009, we installed camera traps at 4 nests from the time of their discovery to the hatching of each nest, in Banco Chinchorro and Cozumel Island. Twenty-one other species were observed to visit crocodile nests. No nest predation was observed but nine species represented some danger to nests and/or hatchlings. Females seemed to remain in the nest vicinity during incubation. There was variability in nest visit frequencies and no nest defense toward human intrusion was observed. Visit frequency by other species at nests decreased with increased crocodile visitation. Crocodiles mainly visited nests on darker nights, corresponding to the visits of species representing greater danger for nests. Repair of the nest by females after disturbance was observed for the first time in wild American crocodiles. Crocodile visits were more frequent at the beginning and the end of incubation, which could represent different antipredation strategies. Although adult crocodiles helped during hatching for the emergence of neonates, hatchling care seemed reduced compared to other crocodile species. We provide the first data on nesting behavior of genetically pure American crocodiles in the Yucatan peninsula, which provides a base for future comparisons with Morelet's crocodiles and their hybrids. [ABSTRACT FROM AUTHOR]

Paratrichosma spp. are capillarid worms that parasitize the abdominal skin of crocodiles. They are likely not a threat to crocodiles' health, but they affect the skins' commercial value. No successful treatment exists against this parasite, and present knowledge of its life cycle is limited. Herein we report new information on Paratrichosoma recurvum occurrence in wild American crocodiles Crocodylus acutus from Mexican Caribbean islands and its relation to environmental (water salinity, temperature, climatic events) and biological (body condition) factors. The percentage of parasitized crocodiles (30.3%) is among the highest recorded in wild crocodilian populations. Small (<40.8 cm total length [TL]) and large (>270 cm TL) crocodiles are less parasitized, probably due to the characteristics of their skin or of the parasite life cycle. Two individuals appeared to have eliminated worms naturally between their capture and recapture. The thorax-abdomen is the most parasitized area of the body of crocodiles. The risk of infection is not associated with the sex of the crocodile, but there was a difference in the proportion of parasitized crocodiles between sites, which could be related to different environmental conditions. The body condition of a crocodile does not seem to be affected by the parasite. Climatic events and water temperature show no effect on the parasitism of crocodiles, but salinity could have an effect. The infection of crocodiles by P. recurvum could depend more on an individual's behavior than on environmental conditions.

Ticks are common ectoparasites of amphibians and reptiles but very few reports of such parasites on crocodylians exist worldwide. Herein, we report the first detailed observations of Amblyomma dissimile Koch, 1844 on the 3 crocodylian species present in Mexico, with the first report of tick parasitism on Crocodylus acutus and the second on Caiman crocodilus chiapasius. This is also the first report of A. dissimile in the state of Quintana Roo. Proportions of infested individuals found in this study ranged from 0.51 to 1.96%, suggesting that tick parasitism in crocodylians is likely opportunistic and occurs when individuals leave the water for terrestrial activities. Tick parasitism does not represent a major threat to crocodylians. The increasing habitat destruction/fragmentation and cattle expansion in southeastern Mexico, however, could increase tick populations and trigger tick parasitism and tick-borne diseases in herpetofauna and other vertebrates, including humans. Thus, studies are needed to better understand these relationships.

Congenital defects in crocodilians have received little interest. In the context of global change and increasing threats to biodiversity, data on birth defects occurring in wildlife could be of importance for estimating the health of species populations and their ecosystems. Herein, we report the first case of amelia (i.e. absence of limbs) in Morelet's crocodiles Crocodylus moreletii from Mexico and the third on the southern Yucatan Peninsula. The crocodile in question was a juvenile (41 cm total length) captured in July 2012 in the Río Hondo, the river that forms the border between Mexico and Belize south of the state of Quintana Roo. The prevalence of this malformation in the C. moreletii population of Río Hondo (0.35%) is similar to that reported in 2 previous cases in Belize. Several causes of birth defects in crocodilians have previously been cited in the literature. Although we do not have relevant information to elucidate this case, we discuss some plausible explanations for this birth defect.

Bacterial cultures and chemical analyses were performed from cloacal and oral swabs taken from 43 American crocodiles Crocodylus acutus and 28 Morelet's crocodiles C. moreletii captured in Quintana Roo State, Mexico. We recovered 47 bacterial species (28 genera and 14 families) from all samples with 51.1% of these belonging to the family Enterobacteriaceae. Fourteen species (29.8%) were detected in both crocodile species and 18 (38.3%) and 15 (31.9%) species were only detected in American and Morelet's crocodiles, respectively. We recovered 35 bacterial species from all oral samples, of which 9 (25.8%) were detected in both crocodile species. From all cloacal samples, we recovered 21 bacterial species, of which 8 (38.1%) were detected in both crocodile species. The most commonly isolated bacteria in cloacal samples were Aeromonas hydrophila and Escherichia coli, whereas in oral samples the most common bacteria were A. hydrophila and Arcanobacterium pyogenes. The bacteria isolated represent a potential threat to crocodile health during conditions of stress and a threat to human health through crocodile bites, crocodile meat consumption or carrying out activities in crocodile habitat. We especially warn about the presence of Salmonella arizonae and S. typhi, which cause enteritis and septicemia in crocodiles and salmonellosis and typhoid fever in humans. The risk of bacterial contamination from crocodiles to humans could increase in the future because of the accelerated destruction of crocodile habitat, which could lead to an augmentation of human-crocodile interactions. Information on bacterial diversity reported here could help in the choice of antibacterial products in case of infections that are of crocodile origin.