Distribution Of Cryptic Species Research Articles

Citizen science sheds light on the cryptic ornate eagle ray Aetomylaeus vespertilio

Abstract The ornate eagle ray Aetomylaeus vespertilio (Bleeker, 1852) is a rare and Endangered species of eagle ray, with a patchy distribution across the Indo‐West Pacific region, for which data are scarce. Citizen science‐sourced data from online social media platforms were used to shed light on the distribution and ecology of the ornate eagle ray. A total of 53 reports of A. vespertilio were found on Facebook, Instagram, Twitter, and YouTube, including four reports of dead specimens. All live reports occurred in shallow reef or lagoon ecosystems. Two individual A. vespertilio specimens were re‐sighted in the same general area following initial identification within 9 and 13 months at Ningaloo Reef and at Lady Elliot Island, Australia, respectively, as confirmed through their dorsal spot patterns. One report was at Richard's Bay in South Africa, the southernmost known location for this species in the Indian Ocean (28°S). Live reports were also reported from the Maldives, the Seychelles, Egypt (Red Sea), Philippines, Palau, and elsewhere on the Great Barrier Reef, Australia. Results indicate that citizen‐collected data can shed light on the occurrence and distribution of cryptic species, as well as complement monitoring programmes.

Detecting the undetectable: Characterization, optimization, and validation of an eDNA detection assay for the federally endangered dwarf wedgemussel, Alasmidonta heterodon (Bivalvia: Unionoida)

Abstract Environmental DNA (eDNA) assays are valuable tools for monitoring the presence and distribution of cryptic species. Like many freshwater mussels, the numbers of dwarf wedgemussel, Alasmidonta heterodon, have dwindled and its range has diminished. As of its listing in 1993, only 10–20 locations were known to persist out of the 70 Atlantic slope locations known historically. A quantitative polymerase chain reaction (qPCR) assay to detect the presence of A. heterodon was developed that uses two probes to accommodate a single‐nucleotide polymorphism (SNP) in the probe‐binding site within the cytochrome c oxidase subunit I (COI) gene. This SNP defines northern and southern major phylogenetic lineages. The primers match exactly the previously determined COI sequences of 20 dwarf wedgemussel individuals representing Atlantic slope populations from North Carolina, Virginia, Maryland, New York, and New Hampshire. Other than for the qPCR assay described here, these primers can be used for sequencing or metabarcoding to further delineate dwarf wedgemussel populations phylogenetically. A simple eDNA preparation method is introduced using flocculation to concentrate free DNA in solution as well as cellular material (including shed animal cells, bacteria, viruses, and dissolved DNA). In addition to the specific application described here, the methodological approaches used in this study are widely applicable to conservation, including, but not limited to, general aquatic biodiversity, phylogenetic studies, and the detection of pathogenic microbes.

Molecular evidence for new sympatric cryptic species of Aedes albopictus (Diptera: Culicidae) in China: A new threat from Aedes albopictus subgroup?

BackgroundAedes (Stegomyia) albopictus (Skuse) is an indigenous species and the predominant vector of dengue fever in China. Understanding of genetic diversity and structure of the mosquito would facilitate dengue prevention and vector control. Sympatric cryptic species have been identified in the Ae. albopictus subgroup in Southeast Asia; however, little is known about the presence and distribution of cryptic species in China. This study aimed to examine the genetic diversity, evaluate potential new cryptic sibling species, and assess the prevalence of Wolbachia infections in field populations.MethodsAedes adult female specimens were collected from five provinces in southern and central China during 2015–2016. Morphological identification was performed under dissection microscope. The mitochondrial DNA cytochrome c oxidase subunit 1 (cox1, DNA barcoding) locus and the ribosomal DNA internal transcribed spacer region 2 (ITS2) marker were used to examine the genetic variation, evaluate cryptic sibling species, and population structure in the field populations. Screening for the presence of Wolbachia was performed using multiplex PCR.ResultsA total of 140 individual specimens with morphological characteristics similar to Ae. albopictus were sequenced for DNA barcoding. Among these, 129 specimens (92.1%) were confirmed and identified as Ae. albopictus. The remaining 11 specimens, from 2 provinces, were identified as 2 distinct sequence groups, which were confirmed by ITS2 marker sequencing, suggesting the existence of potential cryptic species of Ae. albopictus. In Ae. albopictus, we found significant genetic differentiation and population structure between populations collected from different climate zones. Medium to high frequencies of Wolbachia infections were observed in natural Ae. albopictus populations, whereas Wolbachia was infrequent or absent in cryptic species populations.ConclusionsOur findings highlight the population differentiation by climate zone and the presence of novel, cryptic Aedes species in China. The low prevalence of Wolbachia infections in cryptic species populations could reflect either a recent invasion of Wolbachia in Ae. albopictus or different host immune responses to this symbiont in the cryptic species. The study provides useful information for vector control and host-symbiont coevolution. Further study is needed to investigate the potential for arbovirus infection and disease transmission in the emerged cryptic species.

Distribution and Conservation Status of the Caenophidian Snake, Xylophis captaini Gower & Winkler, 2007 in the Western Ghats, India

We update the distribution of the little known Captain's Wood Snake ( Xylophis captaini ) in the Western Ghats, based on new observations and collation of the literature. The Maximum Entropy (MaxEnt) algorithm was used to predict the distribution of the species, which showed potential sites south of 10°N and elevations between 50 and 1000 m amsl. Xylophis captaini is listed as 'Least Concern' under IUCN criteria, and we suggest the possible elevation of its status to the 'Near-Threatened' category on account of its narrow distributional range and general lack of data on its ecology. The present study highlights the utility of niche models in assessing the distribution of cryptic and little known species in biodiversity-rich areas such as the Western Ghats.

Diversity and distribution of cryptic species within the Mugil cephalus species complex in Vietnam

Mugil cephalus sensu lato is a globally distributed complex of cryptic species whose distribution range and evolutionary history remains largely unknown. In the North West (NW) Pacific three species have been identified genetically among fish described morphologically as M. cephalus. Their distribution ranges are largely parapatric and has been proposed to mirror different thermal preferences. To date, few samples have been analyzed from South China Sea, which limits inferences on the evolutionary history of the species complex. We sampled fish identified morphologically as M. cephalus along Vietnamese shores and characterized them using the sequence polymorphism of two mitochondrial genes, the cytochrome oxidase I and cytochrome b. This demonstrated that all three species described in the NW Pacific are present in both northern and southern Vietnamese waters. Although the difference in species abundance reflects those observed in the NW Pacific, no phylogeographic pattern was revealed. In addition, no population structure was observed whatever the species or the distribution range considered, which indicates a significant level of gene flow that maintains genetic homogeneity of the three species. It is also conceivable that each species experienced a recent population expansion from a single ancestral population. Finally we suggest that if the cold waters of the NW Pacific present a physiologic challenge leading to the almost parapatric distribution of the three species, then it is likely that the warm surface temperatures of the South China Sea negate this barrier.