Sacalia Quadriocellata Research Articles

Threatened Species of Amphibians and Reptiles from Vu Quang National Park and Their Conservation Values

Based on five field surveys in 2023 and 2024, we herein provide a list of 24 threatened species of amphibians and reptiles from Vu Quang National Park, Ha Tinh Province. Among them, four species are listed in the Governmental Decree No. 64/2019/ND-CP, 13 species are listed in the Governmental Decree No. 84/2021/ND-CP, 13 species are listed in the CITES Appendices, 17 species are listed in the Vietnam Red Data Book (2007), and 13 species are listed in the IUCN Red List (2024). Seven species with the highest level of conservation priority due to their small populations are Python molurus, Ophiophagus hannah, Platysternon megacephalum, Cuora cyclornata, Cuora galbinifrons, Sacalia quadriocellata, and Indotestudo elongata. The major threat to the herpetofauna of the national park is illegal hunting.

Hainan four-eyed turtles actively select suitable stones to masquerade according to their own morphology.

Masquerade is a form of camouflage in which animals use their body size, shape, and coloration to resemble inanimate objects in their environment to deceive predators. However, there is a lack of experimental evidence to show that animals actively choose objects that match these body parameters. To explore how the Hainan four-eyed turtle, Sacalia insulensis, masquerades using suitable stones, we used indoor video surveillance technology to study the preferences of juvenile S. insulensis for stones of different sizes, shapes, and colors. The results indicated that under normal conditions, during the day, juvenile S. insulensis preferred larger oval or round stones, while at night, they preferred oval stones that were closer to their own size, with no significant preference for stone color during either time. When disturbed (by a researcher swinging their arm back and forth above the experimental setup every hour to mimic a predator), the turtles showed a preference for brown stones that were closer to their size and oval in shape. These findings suggest that juvenile S. insulensis prefer stones that resemble their carapace size and shape to masquerade when undisturbed, and that this preference is reinforced when they masquerade to reduce the risk of predation. The preference for stones that resemble their carapace color is significant only when there is a disturbance. To the best of our knowledge, this is the first study to provide evidence that vertebrates can selectively choose objects that resemble their own morphology for masquerading to reduce predation risk.

Previously Unrecorded Invasive Species and the Unsatisfying Knowledge of Turtle Communities in Northern Vietnam

According to the IUCN, Southeast Asia is the area of the world with the highest number of threatened turtle species. The current status of chelonians is particularly catastrophic in Vietnam. However, there is still a lack of field data to unambiguously support this fact for a few species. To better understand the freshwater turtle diversity and eventually undertake efficient conservation actions, we conducted surveys with local fishers using standardized questionnaires in two independent river systems in northern Vietnam. A total of 112 questionnaires were administered to as many fishers in April and October 2022. We directly observed four sympatric freshwater species (Pelodiscus sinensis, Palea steindachneri, Mauremys sinensis and Sacalia quadriocellata) in Lao Cai and Yen Bai provinces, and two species (Pelodiscus sinensis and Palea steindachneri) in Bac Giang, Hai Duong, Thai Binh, and Hung Yen provinces. Based on the interviews, we added as possible the presence of two other species (Rafetus swinhoei and Pelochelys cantorii) in each of the two study areas. Moreover, we recorded for the first time in Vietnam, two wild individuals of an invasive alien species, the Common snapping turtle (Chelydra serpentina), confirming that the distribution and ecology of turtle species in Vietnam is poorly understood. Furthermore, recent photos (year 2019) of a 38 kg softshell turtle, possibly attributable to Rafetus swinhoei, were recorded from a restaurant in the area. In conclusion, interviews with local fishers have been found to be useful for exploring the likely presence and the local distribution of the various turtle species.

Phylogeography of the endangered "eyed" turtles (genus Sacalia) and the discovery of a lineage derived from natural interspecific hybridization.

The herpetofauna of the Indomalayan bioregion of Asia suffers from severe habitat loss, unsustainable harvesting, and lack of research and conservation. Here, we investigated the range-wide phylogeography of the endangered "eyed" turtles (genus Sacalia, including the Beale's Eyed Turtle S. bealei and the Four-eyed Turtle S. quadriocellata) and discovered a natural interspecific hybrid turtle population in China. Based on phylogeny of the mitochondrial Cytochrome b gene of 101 samples in this study and public data, three major clades and six subclades were identified: S. bealei (SBE) in eastern-southern China, east S. quadriocellata in South China (northern east [SQUen] and southern east [SQUes] subclades), and west S. quadriocellata mainly in Vietnam (northern west [SQUwn], central west [SQUwc], and southern west [SQUws] subclades). We sequenced 16 nuclear DNA loci of 87 samples from SBE, SQUen, SQUes, and SQUwn subclades. Population genetic clustering analysis suggested a structure similar to the mitochondrial phylogeny, where most samples were classified into four genetic clusters corresponding to the four mtDNAsubclades. However, a proportion of samples carrying SQUen mtDNAhaplotypes formed an additional distinct cluster SHY. Those samples are found in the contact zone of the two species bearing mosaic and intermediate morphological characteristics. We detected an admixed ancestry in SHY from SBE and SQUen that conformed to an intrapopulation breeding scenario for at least hundreds of generations after the initial hybrid event, leading to a conclusion that SHY is a distinct and near-panmictic population derived from natural interspecific hybridization. In addition, SQUes (Hainan Island endemic) is of special concern due to significant isolation and low genetic diversity. We suggest that seven evolutionarily significant units should be recognized to facilitate appropriate conservation actions. These findings also highlight the urgent need for further herpetological research and conservation in this region.

Quantifying shape similarity between prey and uninteresting models to study animal masquerade

Abstract Masquerade occurs when an organism resembles an inedible or uninteresting object (model), such as a leaf, stick, or stone. The shapes of many species are described as similar to those of models in their microhabitats, but these similarities have not been quantified effectively. To describe the shape similarity between an animal and a model, we applied a shape description method in a field study of the four-eyed turtle (Sacalia quadriocellata). Our results showed that shape similarity between turtles and stones in the Hezonggou River was significantly higher midstream than that upstream and downstream. In line with these findings, masquerade efficiency was highest for turtles in the midstream area, with both inexperienced and experienced human ‘predators’. Masquerade efficiency was positively correlated with shape similarity in all stream sections. Shape similarity ranged from 0 to 1, with <0.65 indicating low masquerade efficiency and >0.80 indicating high masquerade efficiency. Our quantitative method was able to provide data that could be used to form an ecologically plausible argument; thus, shape similarity can be used to assess animal’s masquerade efficiency. This method will be of considerable use in future animal masquerade research.

Threats from wildlife trade: The importance of genetic data in safeguarding the endangered Four-eyed Turtle (Sacalia quadriocellata)

Wildlife trade has been considered one of the largest threats to biodiversity in Southeast Asia. Many vertebrates, such as pangolins, elephants and turtles have been heavily hunted as a result of high demand from emerging markets in China and other countries in the region. In Vietnam, over-exploitation of turtles over several decades to supply the international trade has extirpated numerous populations and driven several species to the brink of extinction. To reverse this trend, conservation measures, such as re-introduction of confiscated or captive-bred animals to their native habitats, should be implemented to recover severely declined local populations. For species with a complex phylogeographic structure, however, it is crucial to understand geographic patterns of genetically-distinct populations to avoid releasing animals of unknown origin to wrong localities. In this study, we investigate the phylogeographic pattern of the Four-eyed Turtle (Sacalia quadriocellata), a widely traded species, which occurs in southern China, northern and central Laos and much of Vietnam, using samples with known localities and those collected from the local trade. Our range-wide phylogenetic and network study, based on the complete mitochondrial cytochrome b gene, recovered at least three major clades and seven subclades within the species range. Amongst these, two subclades, one from northern Annamites, Vietnam and the other from north-eastern Laos, are newly discovered. The fine scale phylogeographic analysis helped us to assign misidentified sequences from GenBank and those from confiscated animals with unknown origin to well-defined geographic populations. The results highlight the importance of incorporating samples collected from the local trade and the wild in genetic analyses to support both ex-situ and in-situ conservation programmes of highly-threatened species in accordance with the IUCN’s One Plan Approach.

Characterization and comparison of mitogenomes of three ‘eyed’ turtles Sacalia spp

In this paper, we characterized the mitogenomes of three ‘eyed’ turtles, the Beal’s Eyed turtle (Sacalia bealei), the Four Eye-spotted turtle (S. quadriocellata), and the Hainan Four Eye-spotted turtle which was a unique lineage in the four-eyed turtle and considered as an independent species S. insulensis recently. The full lengths of the S. bealei and S. quadriocellata mitogenomes are 16,564 bp, and 16,555 bp, respectively, while the length of partial mitochondrial genome of S. insulensis is 16,433 bp without tailed part of D-loop. All the genes exhibit the typical mitochondrial gene arrangement and transcribing directions of turtles. Phylogenetic analysis indicating that a deep divergence about 7.8% p distance was found between S. bealei and (S. quadriocellata + S. insulensis), and the divergence (2.8% in patristic distance) between S. quadriocellata and S. insulensis is comparable with other closely related species in turtles.

Background matching and camouflage efficiency predict population density in four-eyed turtle (Sacalia quadriocellata)

Background matching is an important way to camouflage and is widespread among animals. In the field, however, few studies have addressed background matching, and there has been no reported camouflage efficiency in freshwater turtles. Background matching and camouflage efficiency of the four-eyed turtle, Sacalia quadriocellata, among three microhabitat sections of Hezonggou stream were investigated by measuring carapace components of CIE L*a*b* (International Commission on Illumination; lightness, red/green and yellow/blue) color space, and scoring camouflage efficiency through the use of humans as predators. The results showed that the color difference (ΔE), lightness difference (ΔL*), and chroma difference (Δa*b*) between carapace and the substrate background in midstream were significantly lower than that upstream and downstream, indicating that the four-eyed turtle carapace color most closely matched the substrate of midstream. In line with these findings, the camouflage efficiency was the best for the turtles that inhabit midstream. These results suggest that the four-eyed turtles may enhance camouflage efficiency by selecting microhabitat that best match their carapace color. This finding may explain the high population density of the four-eyed turtle in the midstream section of Hezonggou stream. To the best of our knowledge, this study is among the first to quantify camouflage of freshwater turtles in the wild, laying the groundwork to further study the function and mechanisms of turtle camouflage.

Reptile Diversity in Food Markets in Laos

Abstract: Wildlife is one of the most important food resources in Laos, and many species are sold at the local markets, but the fauna of the country remains poorly known. As a result of human impacts, including overharvesting for food consumption, many wild animals in Asia face imminent extinction. Our study focused on reptile species that were sold at local markets in Laos. The data were recorded in February, August, and September 2013. We found 16 reptile species in the local market: eight freshwater turtle species, Cuora amboinensis, Cyclemys oldhamii, Malayemys macrocephala, M. subtrijuga, Sacalia quadriocellata, Siebenrockiella crassicollis, Amyda ornata, and Pelodiscus sinensis, one tortoise species, Manouria impressa, four lizard species, Calotes versicolor, Physignathus cocincinus, Varanus nebulosus and V. salvator, and three snake species, Malayopython reticulatus and two species of Ptyas. Most of these reptile species are used by local people as foods. Two species are recorded for the first time...

Haemogregarines of freshwater turtles from Southeast Asia with a description of Haemogregarina sacaliae sp. n. and a redescription of Haemogregarina pellegrini Laveran and Pettit, 1910.

The uniform morphology of the developmental stages of Haemogregarina species and the insufficient information supplied by the simplistic descriptions of previous authors complicates their differential diagnosis and proper species identification. In this study, we detected Haemogregarina spp. in 6 out of 22 (27.2%) examined turtles originating from Southeast Asia, Malayemys subtrijuga (n = 4), Sacalia quadriocellata (n = 1) and Platysternon megacephalum (n = 1), and compared them with the available literature data. Microscopic analysis of our isolates distinguished 2 morphological species, Haemogregarina pellegrini and one new species, being described in this paper as Haemogregarina sacaliae sp. n. Phylogenetic analyses based on 1210 bp long fragment of 18S rDNA sequences placed both haemogregarines firmly within the monophyletic Haemogregarina clade. Isolates of H. pellegrini from 2 distantly related turtle hosts, M. subtrijuga and P. megacephalum, were genetically identical. Despite the fact that numerous Haemogregarina species of turtles have been described, the incompleteness of the morphological data and relatively low host specificity provides the space for large synonymy within this taxon. Therefore, a complex approach combining microscopic analyses together with molecular-genetic methods should represent the basic standard for all taxonomic studies.

Twenty polymorphic microsatellite loci developed from the four-eyed turtle (Sacalia quadriocellata)

Twenty polymorphic microsatellites were isolated from the four-eyed turtle, Sacalia quadriocellata with a partial genomic library enriched for tandem repeat sequences of (CA)12 and (GA)12. Polymorphism was investigated for these markers in 22 individuals collected from Guangdong Provincial Wildlife Rescue Center in Guangzhou, China. The allele number ranged from 4 to 13 per locus, with the average of 8. The observed and expected heterozygosity varied from 0.300 to 0.947 with an average of 0.635 and 0.317 to 0.909 with an average of 0.771 respectively. Exact tests for HWE revealed that 10 of 20 loci significantly deviated from Hardy–Weinberg equilibrium after Bonferroni correction. Only one pair of loci (SYB56 and SYB81) showed significant linkage disequilibrium. These microsatellite loci will be useful for population genetics, ecology and determining the conservation status of imperiled populations in Sacalia quadriocellata.

Coelioscopic-assisted prefemoral oophorectomy in chelonians

To describe a coelioscopic-assisted prefemoral oophorectomy technique for use in chelonians. Descriptive report. 11 adult female turtles (6 red-eared sliders, 2 box turtles, 1 painted turtle, 1 four-eyed turtle, and 1 Chinese red-necked pond turtle). Five turtles required oophorectomy because of reproductive tract disease; the remaining 6 underwent elective oophorectomy. Turtles were anesthetized and positioned in dorsal recumbency. An incision was made in the prefemoral fossa, and a 2.7-mm rigid endoscope was inserted into the coelomic cavity and used to identify the ovaries. Each ovary was grasped with forceps and exteriorized through the prefemoral incision. The ovarian vasculature was ligated, and the mesovarium was transected. Closure was routine. In 8 turtles, bilateral oophorectomy was performed through a single incision. In 2 turtles, unilateral oophorectomy was performed in an attempt to maintain reproductive potential. In 1 turtle with a unilateral ovarian remnant from a previous surgery, unilateral oophorectomy was performed. Nine turtles recovered. One box turtle with severe hepatic lipidosis died 7 days after surgery. A second box turtle died 2 days after removal of retained eggs and a large bacterial granuloma. Results suggest that coelioscopic-assisted prefemoral oophorectomy is a practical and safe method for treating reproductive disorders and performing elective oophorectomy in turtles. This technique represents a potential alternative to plastron osteotomy in sexually mature chelonians.