Caiman Latirostris Research Articles

Serum Biochemical Profile, Intestinal and Liver Histomorphometry of Captive Broad-Snouted Caiman (Caiman latirostris) Fed With a Diet Enriched With Soybean (Glycine max).

The impact of plant-based diets on crocodilians is unclear. Serum profiles and histomorphometry provide valuable insights into their nutritional and physiological status. This study aims to elucidate the impact of three levels of soybean meal substitution combined chicken by-product minced on the growth and health of broad-snouted caiman (Caiman latirostris). The research assesses the effects of diets supplemented with soybean meal on the blood biochemical profile, intestinal histomorphometry, and hepatic parameters of C. latirostris, providing essential information for understanding on the implications of dietary changes in this species. Forty-eight 6-month-old broad-snouted caimans were assigned to three dietary groups (0%, 25%, 40% soybean meal). Over a period of 90 days, data on growth, food consumption, serum biochemical analysis, intestinal and hepatic morphometry were recorded. The results showed that diets containing higher levels of soybean meal did not significantly affect growth, feed intake or serum profiles of total protein, albumin and cholesterol. However, changes in intestinal morphology were observed, with longer and wider villi in the animals feed with diets with soybean meal, indicating a gradual adaptation to new feeding diets. The presence of soybean meal reduced serum glucose and triglyceride profiles and hepatic lipid accumulation without affecting macronutrient digestion and absorption, considered beneficial for the caiman's health. This study provides valuable insights into the inclusion of soybean meal in the diet of Caiman latirostris and its effects on the intestines, liver, and physiology. It also highlights the importance of considering nutritional management as a key tool in improving the well-being and health of crocodilians in captivity.

GPS-telemetry as a method to assess nest attendance by a female broad-snouted caiman Caiman latirostris

Crocodylians exhibit parental care, guarding their eggs during incubation to ensure offspring survival. We present the first description of nest attendance of a wild broad-snouted caiman using GPS-telemetry. During the reproductive season of 2022, we tracked a 1.8-metre female in the Tapacurá reservoir, a water source bordered by Atlantic Forest remnants and human settlements in north-eastern Brazil. Telemetry data revealed that 75.8% of the female’s position records were near the nest, suggesting parental care and nest protection. However, the female periodically returned to water. We observed no differences in proximity to the nest between day and night-time, which could be possibly related to different egg predators in the area foraging at different times of the day. Furthermore, the period when the nest was unattended could be associated with either feeding activities or avoidance of human presence. This research brings light on an important part of the reproductive behaviour of broad-snouted caimans in their natural environment, highlighting the importance of GPS-telemetry as a tool for monitoring reproductive behaviour of crocodylians, while contributing to understanding their biology under human-influenced settings. Keywords: Atlantic Forest, crocodylian, movement, parental care, reproductive biology

Effects of anticoagulants time storage on stable isotope values of crocodilians’ blood tissues

ABSTRACT Rapid coagulation of reptile blood often hinders its use in studies in remote and difficult-to-access areas, necessitating chemical preservation. Therefore, understanding the potential effects of anticoagulants on the isotopic compositions of blood is essential to avoid issues in interpreting the results for ecological studies. In this study we aimed to verify whether the storage time of the blood tissue in anticoagulants can influence its isotopic compositions of the broad-snouted caiman (Caiman latirostris), an ectothermic top predator from eastern South America. Blood samples were obtained from ten adult females of C. latirostris from a commercial breeding facility in 2015. Samples were stored in vials containing ethylenediaminetetraacetic acid (EDTA) and sodium heparin (SH) and centrifuged after 2 and 8 h to separate red blood cells and plasma. No effect of time was found on the δ13C and δ15N of whole blood, plasma, and red blood cells in contact with the two types of anticoagulants, EDTA and SH. The findings have practical implications for researchers in this field, as they suggest that anticoagulants can be used effectively for at least eight hours under refrigeration.

New taxa of giant caimans from the southernmost hyperdiverse wetlands of the South American late Miocene

Here we present a comparative anatomical study of large late Miocene alligatorids of Argentina (Ituzaingó Formation), in which we analyse their taxonomy, morphological disparity, and phylogenetic relationships. ‘Caiman lutescens’ and Caiman gasparinae are two giant Miocene Argentinean caimanines that are assigned to the genus Caiman. ‘Caiman lutescens’ was originally described based on the large size of several isolated cranial and postcranial elements. In this study we consider that the lectotype of ‘C. lutescens’, an articulated left premaxilla and maxilla (MACN-Pv 5416), is morphologically indistinguishable from rostral morphotypes present in other jacarean caimanines, like Caiman latirostris and Caiman wannlangstoni, and therefore ‘C. lutescens’ is here considered a nomen dubium while MACN-Pv 5416 is an indeterminate Jacarea. A partial skull table, MACN-Pv 13551, was originally and historically referred to ‘C. lutescens’, and even wrongly considered its holotype, but it is here redescribed and reinterpreted as the holotype of a new genus and species. Additionally, after the comparative anatomical study of the holotype of C. gasparinae (MLP-Pv 73-IV-15-1), we conclude that it shows a distinctive combination of skull morphological features that allows it to be distinguished from other caimanines, including extant Caiman species. This situation and the results of the phylogenetic analyses lead us to erect a new genus for this species, which results in a new nomenclatorial combination. These new results support the idea that the alligatorid assemblages of the South American late Miocene wetlands were highly diverse at high latitudes (c. 30–35°S), as evidenced by the taxonomic diversity and morphological disparity present in the crocodylian assemblage of the Ituzaingó Formation in Paraná. The close relationship between the two new taxa + Mourasuchus spp. with Purussaurus spp. recovered in the present study reinstates the question of how to define the Caiman genus, as well as when and where it originated. http://zoobank.org/urn:lsid:zoobank.org:pub:6096F826-7CCA-4795-B4CF-5AFF87D6EBCC

Antibodies against Leptospira spp. in Free-living and Captive Broad-snouted Caiman (Caiman latirostris) and Free-living Yacare Caiman (Caiman yacare) in Brazil.

We evaluated antibodies against Leptospira spp. in both free-living and captive Caiman latirostris from Atlantic Forest, and free-living Caiman yacare from Pantanal, Brazil, by using a microscopic agglutination test. Overall seropositivity was 17%, with rates of 36% in captive C. latirostris (n=4/11) and 18% in free-living C. yacare (n=4/22).

Crocodilian Phallic Malformations and Anomalies

Abstract Phallic malformations directly impact crocodilian copulatory function and thus could impact reproductive success in individual animals. This case series characterizes malformations observed and the implied reproductive consequences. We assessed a range of phallic malformations observed in saltwater crocodile (Crocodylus porosus), Nile crocodile (Crocodylus niloticus), broad-snouted caiman (Caiman latirostris), and Cuban crocodile (Crocodylus rhombifer) during veterinary examinations or postmortem studies and characterized observation into the following categories: amputation, phallic glans malformations, sulcus spermaticus obstruction, and prolapse. Through detailed descriptions of these anomalies, we discuss potential reproductive health impact based on current knowledge across crocodilian species. When considering captive management of breeding stock, it is vital to examine individual efficacy at achieving proper intromission and insemination. Therefore, full reproductive examination in males should be part of routine examination to best manage individuals with such anomalies.

Artisanal fishing affects the local distribution of broad‐snouted caiman (Caiman latirostris) within the Atlantic Forest of Brazil

Abstract Artisanal fishing is an important subsistence practice in freshwater habitats worldwide, but overexploitation threatens the conservation of several nontarget species including crocodylians. We investigated the effects of artisanal fishing on the distribution of a population of broad‐snouted caiman (Caiman latirostris) inhabiting the Tapacurá reservoir, within the highly altered and threatened Atlantic Forest biome. We conducted spotlight surveys to detect caimans and gillnets deployed in the reservoir from April 2015 to June 2022. We evaluated temporal differences in gillnet encounter rates and the relationship between caimans and gillnet distribution. Gillnet encounter rates remained consistent year‐round, while caiman encounter rates were highest near gillnets, especially in the river channel and in forested margins. Caimans are opportunistic predators attracted by tangled fish in gillnets and likely prefer habitats with increased fish abundance. Future research should continue monitoring the interaction between caimans and fishing and include local communities in conservation efforts.

Occurrence of Caiman latirostris and Caiman yacare in the Middle Delta of the Paraná River, Argentina

Occurrence of Caiman latirostris and Caiman yacare in the Middle Delta of the Paraná River, Argentina

Exposure to atrazine and endosulfan alters oviductal adenogenesis in the broad-snouted caiman (Caiman latirostris).

The molecular pathways involved in oviductal adenogenesis are highly conserved among vertebrates. In this work, we study the histomorphological changes and molecular pathways involved in Caiman latirostris oviductal adenogenesis and the effects of in ovo exposure to environmentally relevant doses of endosulfan (END) and atrazine (ATZ) on these processes. To this end, the histomorphological changes at epithelial and subepithelial compartments, the protein expressions of β-catenin and Wnt-7a, and the gene expression of metalloproteinases (MMPs) and its inhibitors (TIMPs) were evaluated as biomarkers of oviductal adenogenesis in prepubertal juvenile C. latirostris. Exposure to END altered adenogenesis-related epithelium characteristics and mRNA expression of MMP2, MMP9, and TIMP1. Exposure to ATZ increased the width of the subepithelial stroma with loosely arranged collagen fibers and increased β-catenin expression in buds (invaginated structures that precede glands). The results demonstrate that in ovo exposure to ATZ and END alters oviductal adenogenesis at tissue, cellular, and molecular levels. An altered oviductal adenogenesis could impair fertility, raising concern on the effects of pesticide pollution in wildlife and domestic animals.

Increasing Population Status of Broad-Snouted Caiman (Caiman latirostris) Based on Sustainable Use Strategies in a Managed Protected Area in Santa Fe, Argentina.

People and crocodilians have engaged in interactions since the earliest human settlements. After many years of escalating non-regulated use, coupled with emerging threats such as habitat modification, environmental pollution, and the exponential growth of human populations, natural crocodilian populations have been pushed to the brink of extinction. To prevent this, various initiatives have implemented strategies to prevent local extinction. Reinforcing wild populations through reintroductions and head-starting programs has been considered the safest approach to recovering crocodilian populations. Subsequently, the concept of sustainability emerged. In the case of many historically exploited crocodilian species, it became evident that rational utilization need not adversely affect population status; on the contrary, there were clear signs of recovery when local communities were involved. In 1990, the broad-snouted caiman (Caiman latirostris) was in a critical state due to decades of poaching and the aforementioned threats. In response, the "Monitoring and restocking program of the broad-snouted caiman for management purposes", commonly known as Proyecto Yacaré, was established to study population abundance and assess the biological, ecological, and social response to this management methodology. As a result of the eggs's harvest, a proportion equivalent to or greater than what would have survived in natural conditions was released into the original habitat where the eggs were collected. The surplus was allocated for leather and meat production with a focus on economic and environmentally sustainable practices, without affecting biodiversity or threats to the managed species. The in situ work carried out by this program has been crucial for the recovery of broad-snouted caiman populations under the "incentives for conservation" system, whereby local communities receive benefits for nest identification and egg harvesting. Over time, conservation incentives have become significant contributors to regional economies. This study illustrates how C. latirostris populations increased due to the implementation of egg harvesting by local communities in a natural reserve for management purposes. This population increase was detected through continuous night monitoring and an analysis of the number of nests in the area. Currently, C. latirostris populations have transitioned from being among the most threatened to becoming one of the most abundant throughout their distribution area. Based on the analyzed information, we may affirm that the commercial value of these species is one of the most relevant aspects contributing to the sustainability of these programs, primarily due to the change in perception generated among local communities. Therefore, identifying and controlling factors affecting these programs are fundamental for the conservation of these species.

A true facultative carnivore? Effects of replacing ground chicken carcasses with soybean meal on the growth of captive broad-snouted caiman (Caiman latirostris) and its economics implications.

A specific diet for broad-snouted caiman, Caiman latirostris has not been designed despite the value of farm-raised caiman as an aquaculture product. To fill this gap, the objectives of this study were to evaluate the performance dietary replacement of ground chicken carcasses by of soybean meal (SM) as diet complement for C. latirostris. We conducted a 3-month growth trial to determine effects of graded levels of dietary SM on caiman growth as measured by increase in body length, body weight gain, food consumption (FC) and food conversion rate (FCR). Forty-eight hatchling caimans were fed with diets, composed primarily of practical feed ingredients, with 0, 25, or 40% dietary SM. Diets were fed three times per week for 90 days under temperature controlled. Body lengths and body weights were measured at 30-day intervals, and FC samples were taken between the 31-60-day interval. The results of this study indicate that the inclusion of SM in the diet of C. latirostris at levels of 25% increases in body length, body weight gain, FC and improve the FCR indicated that a concentration of 25% dietary SM (as fed) was adequate for growth of caimans under the conditions of this study. Results suggest that SM have a real nutritional contribution in the diet of broad-snouted caiman and can be used as an ingredient of the diet of the crocodilians raised in captivity, reducing production costs for sustainable use and conservation programs of this species.

Camera-traps detect the maned wolf preying on broad-snouted caiman eggs

The maned wolf (Chrysocyon brachyurus) is a South-American canid of which conservation guidelines have been implemented due to its population vulnerability. Its trophic ecology demonstrates an omnivorous and opportunistic diet, and even flexibility in response to anthropogenic disturbances. Among the food items identified, the consumption of reptiles is scarce, and includes snakes and lizards. We monitored broad-snouted caiman (Caiman latirostris) nests during four nesting seasons through camera trapping, in savannas and grasslands areas, and recorded maned wolves feeding on caiman eggs during periods of drought. The consumption of an uncommon item, even at low frequency, suggests that camera trapping could become a complementary tool for studying the dietary habits of the maned wolf. Caimans have been a priority for conservation, while maned wolves are currently being released and reintroduced in order to reverse their vulnerable population status. This trophic interaction must be monitored in the long term, to project integral conservation strategies that include both emblematic species.

Arthrological reconstructions of the pterosaur neck and their implications for the cervical position at rest.

The lack of any pterosaur living descendants creates gaps in the knowledge of the biology of this group, including its cervical biomechanics, which makes it difficult to understand their posture and life habits. To mitigate part of this issue, we reconstructed the cervical osteology and arthrology of three pterosaurs, allowing us to make inferences about the position of the neck of these animals at rest. We used scans of three-dimensionally preserved cervical series of Anhanguera piscator, Azhdarcho lancicollis and Rhamphorhynchus muensteri for the reconstructions, thus representing different lineages. For the recognition of ligaments, joint cartilages, and levels of overlapping of the zygapophyses, we applied the Extant Phylogenetic Bracket method, based on various extant birds and on Caiman latirostris. We inferred that pterosaur intervertebral joints were probably covered by a thin layer of synovial cartilage whose thickness varied along the neck, being thicker in the posterior region. Ignoring this cartilage can affect reconstructions. According to the vertebral angulation, their neck was slightly sinuous when in rest position. Our analyses also indicate that pterosaurs had segmented and supra-segmented articular cervical ligaments, which could confer stabilization, execute passive forces on the neck and store elastic energy.

Predation of a neonate caiman, Caiman latirostris (Daudin, 1802) by red fire ants Solenopsis sp. in Atlantic Forest, North-eastern Brazil

Predation of a neonate caiman, Caiman latirostris (Daudin, 1802) by red fire ants Solenopsis sp. in Atlantic Forest, North-eastern Brazil

Morphological comparison of the larynx and trachea of Chelonia mydas (Linnaeus, 1758), Caiman yacare (Daudin, 1802) and Caiman latirostris (Daudin, 1802).

The larynx is in the lower respiratory tract and has the function of protecting the airways, controlling, and modulating breathing, assisting the circulatory system, and vocalizing. This study aims to describe the anatomy and histology of the skeleton of the larynx and trachea of the species Chelonia mydas, Caiman yacare and Caiman latirostris. The study was conducted at the Federal University of Espírito Santo (UFES), using nine specimens of Ch. mydas, 20 of Ca. yacare and four of Ca. latirostris. Samples of the larynx and trachea were collected, fixed, and sent for dissection of the structures and subsequent macroscopic analysis. For histology, samples were processed by the routine paraffin embedding method and stained with hematoxylin-eosin and Verhoeff. For the three species, two arytenoid cartilages, a cricoid cartilage, a hyoid apparatus composed of a base and two horns were found. In Ch. mydas, two structures called thyroid wings were observed, not found in crocodilians. The trachea of crocodilians presented incomplete tracheal rings and musculature, while the trachea of Ch. mydas presented complete tracheal rings. Histologically, the entire cartilaginous skeleton of the larynx of the three species, as well as the tracheal rings, are constituted by hyaline cartilage.

Body Condition of Reproductive and Non-Reproductive Broad-Snouted Caiman Females.

In this work, we calculated the body condition indices, K-Fulton and scaled mass index (SMI), of reproductive and non-reproductive Caiman latirostris adult females as an indication of stored energy. We considered 87 adult females captured from 2001 to 2018, both reproductive and non-reproductive. The body condition was calculated considering two scenarios: (a) only the weight of the female, and (b) the sum of the weight of the female and the average dry weight of her nest. We tested the difference in body condition between reproductive and non-reproductive females. We also evaluated the minimal body condition required to guarantee that females above it are reproductive by drawing a line that separated the body condition of strictly reproductive individuals from those that may or may not be reproductive. Reproductive females had better body condition than non-reproductive ones. Our SMI.S line separated almost 70% of the reproductive females. Based on our results, we can guarantee that a female whose body condition is above the line will reproduce, although not all those females below the line are non-reproductive, as a few of those under the line will nest. With this information, we have one more biological indicator to take into account when making management and conservation decisions.

Do ontogenetic changes during incubation interfere with the interpretation of incubation mode in dinosaur eggs?

ABSTRACT Dinosaurs are oviparous reptiles that belong to Archosauria and whose closest modern relatives are crocodiles and birds. This is why, to shed light on the study of dinosaur reproduction, we conducted a test with the species Caiman latirostris (Crocodylia), a living archosaur. This paper focuses on the study of the embryos’ effect on the eggshells of Caiman latirostris during incubation. A total of 30 eggs from four nests including both embryonated and non-embryonated eggs were artificially incubated under the same conditions (incubation medium and temperature) to observe changes in eggshell structure throughout embryonic development. We found significant differences between eggs, in the embryonated eggshells we observed that the continuous calcium layer, became thinner, while at the same time we recorded an increase in the porosity of the eggshells both in the polar and equatorial regions. These changes could explain the variability recorded in fossil deposits with broods, where shells of the same oospecies were found at different levels and with differences in porosity and thickness. The results of this study will contribute to the methodology behind the inference of nesting environment and nesting strategies (buried, semi-buried or exposed) for fossil eggs, which typically utilises calculations of water vapour conductance.

The paleoichnofauna in bones of Brazilian Quaternary cave deposits and the proposition of two new ichnotaxa

The Quaternary vertebrate paleontology of the Brazilian Intertropical Region is well-known, but there are only a few publications on bone ichnology. In this paper, we analyzed trace fossils in 23 bones of the Gruna das Três Cobras, Complexo Suíço, and F3 caves, which are located in Bahia and Rio Grande do Norte states, in the Brazilian Intertropical Region. We discovered gnaw marks assigned to Machichnus and bite marks attributed to Nihilichnus, as well as insect modifications referring to single (Cuniculichnus, Gunnellichnus, Karethraichnus, and Osteocallis) and multiple behaviors (Munitusichnus, and Taotieichnus). Additionally, we proposed the new ichnospecies Nihilichnus sulcatus n. isp. (bite mark) and Cuniculichnus cascudoi n. isp. (insect feeding mark). Regarding the predation/scavenger marks, Protocyon troglodytes was the probable primary modification agent, but some traces may also be attributed to Smilodon populator and Caiman latirostris. Cuniculichnus, Karethraichnus, Munitusichnus, and Osteocallis are attributed to dermestids, whereas termites probably produced Gunnelichnus and Taotieichnus.

Revisitando a diversidade e estrutura genética de Caiman Latirostris (Alligatoridae: Crocodylia) no Brasil

The distribution of the broad-snouted caiman is concentrated in the Brazilian coastal area, the area with the highest urbanization rate in the country. The anthropic pressure makes constant monitoring a necessary effort. Aiming to conserve the species and expand genetic information of Caiman latirostris, we analyzed the genetic diversity and structure of a population in Serra – ES. We compared it with analyzed data of populations distributed in Brazil. We used ten microsatellite markers from 39 samples collected from five lakes in the industrial complex of Serra – ES and data obtained from the literature with information from the same genetic markers for comparative analysis. We observed that the population of ES is genetically isolated from the other nine Brazilian populations. There are high genetic similarities among the lakes, probably due to the low geographic distance (between 100 m and 3 km) among them. The mean heterozygosity observed for the ES population was 0.434, indicating that this population has lower genetic diversity than the others already studied around Brazil (average of 0.54) and a high inbreeding index (0.271) probably related to the isolation of the population.

Contractile function of fasting and digesting broad-snouted caiman (Caiman latirostris)

Feeding regimes are a critical process to ensure survival and reproduction, which modulate several behavioral and physiological patterns of ectotherms, especially cardiovascular adjustments. However, crocodilian myocardial contractile function after food intake remains understudied. We investigated the importance of ventricular myocardial contractility during digestion in the broad-snouted caiman, Caiman latirostris Daudin, 1801. Isometric ventricle preparations and Ca2+-handling protein expression were used to investigate the effects of prolonged fasting (30 days) and feeding (48 h after feeding on meals at 15% of body mass) on cardiac function. Upon feeding, there was no significant difference in relative ventricular mass. The cardiac response of the caiman to digestion was characterized by upregulation of the Na+/Ca2+ exchanger expression and an increase in myocardial contractility (positive inotropism and lusitropism) within the physiological range of heart rate. The digesting caiman's ventricular myocardium was able to maintain faster kinetics of contraction and relaxation, allowing for significantly increased cardiac pumping capacity at higher pacing frequencies. Our results demonstrated that the myocardium of broad-snouted caimans exhibits specializations in excitation–contraction coupling, which can provide a means to support high cardiovascular performance during digestion.