Morphological Ambiguity Research Articles

Assessing Species-Level Identification of Some Cryptic Frog Species of Bangladesh Using 16s and 12s Rrna Genes

In recent years, a number of new and undescribed anuran species are being discovered at a very fast rate in South and Southeast Asia. With the revelation of more and more species that were previously considered to be some other species, accurate identification of these morphologically cryptic anurans based on morphology alone have become difficult. In this study, we attempted specieslevel identification of 15 frog specimens belonging to the families Dicroglossidae and Microhylidae of Bangladesh by analyzing their 16S and 12S rRNA gene sequences. The collected specimens were successfully identified to be belonging to eight different species, namely Fejervarya dhaka, F. asmati, F. pierri and F. orissaensis; Euphlyctis kalasgramensis and Euphlyctis sp.; Microhyla berdmorei and M. mymensinghensis using BLAST and maximum likelihood analyses. In some cases the frog samples showed morphological resemblance but after molecular analysis they were found to be different and in another case morphologically distant samples were found to be molecularly similar. For example, two of the specimens (ESP 01, ESP 02) turned out to be E. kalasgramensis at molecular analysis, however, did not match with the morphological and morphometric descriptions (specially snout-vent length) described previously. Moreover, a species is suspected to be still undescribed and another species namely M. berdmorei was thought to be absent in Bangladesh which has been recorded in our study. Thus, morphological ambiguity strengthens the urge for molecular analysis for proper identification. Dhaka Univ. J. Biol. Sci. 33(2): 27-52, 2024 (July)

API Entity and Relation Joint Extraction from Text via Dynamic Prompt-tuned Language Model

Extraction of Application Programming Interfaces (APIs) and their semantic relations from unstructured text (e.g., Stack Overflow) is a fundamental work for software engineering tasks (e.g., API recommendation). However, existing approaches are rule based and sequence labeling based. They must manually enumerate the rules or label data for a wide range of sentence patterns, which involves a significant amount of labor overhead and is exacerbated by morphological and common-word ambiguity. In contrast to matching or labeling API entities and relations, this article formulates heterogeneous API extraction and API relation extraction task as a sequence-to-sequence generation task and proposes the API Entity-Relation Joint Extraction framework (AERJE), an API entity-relation joint extraction model based on the large pre-trained language model. After training on a small number of ambiguous but correctly labeled data, AERJE builds a multi-task architecture that extracts API entities and relations from unstructured text using dynamic prompts. We systematically evaluate AERJE on a set of long and ambiguous sentences from Stack Overflow. The experimental results show that AERJE achieves high accuracy and discrimination ability in API entity-relation joint extraction, even with zero or few-shot fine-tuning.

Evaluation of identification methods for cryptic Bactrocera dorsalis (Diptera: Tephritidae) specimens: combining morphological and molecular techniques.

The potential for population genomics to elucidate invasion pathways of a species is limited by taxonomic identification issues. The Oriental fruit fly pest, Bactrocera dorsalis (Hendel) belongs to a complex in which several sympatric species are attracted to the same lure used in trapping and are morphologically cryptic and/or reported to hybridize. In this study, we evaluated the taxonomic ambiguity between B. dorsalis and 2 major cryptic species, based on morphological expertise and 289 target specimens sampled across the whole distribution range. Specimens were then subjected to DNA sequence analyses of the COI mitochondrial barcode and the EIF3L nuclear marker to evaluate the potential for molecular identification, in particular for specimens for which morphological identification was inconclusive. To this aim, we produced reference datasets with DNA sequences from target specimens whose morphological identification was unambiguous, which we complemented with 56 new DNA sequences from closest relatives and 76 published and curated DNA sequences of different species in the complex. After the necessary morphological observation, about 3.5% of the target dataset and 47.6% of the specimens from Southeast Asian islands displayed ambiguous character states shared with B. carambolae and/or B. occipitalis. Critical interpretation of DNA sequence data solved morphological ambiguities only when combining both mitochondrial and nuclear markers. COI discriminated B. dorsalis from 5 species; EIF3L and ITS from another species. We recommend this procedure to ensure correct identification of B. dorsalis specimens in population genetics studies and surveillance programs.

Compensatory Base Changes in ITS2 Secondary Structure Alignment, Modelling, and Molecular Phylogeny: An Integrated Approach to Improve Species Delimitation in Tulasnella (Basidiomycota).

The delimitation of species of Tulasnella has been extensively studied, mainly at the morphological (sexual and asexual states) and molecular levels-showing ambiguity between them. An integrative species concept that includes characteristics such as molecular, ecology, morphology, and other information is crucial for species delimitation in complex groups such as Tulasnella. The aim of this study is to test evolutionary relationships using a combination of alignment-based and alignment-free distance matrices as an alternative molecular tool to traditional methods, and to consider the secondary structures and CBCs from ITS2 (internal transcribed spacer) sequences for species delimitation in Tulasnella. Three phylogenetic approaches were plotted: (i) alignment-based, (ii) alignment-free, and (iii) a combination of both distance matrices using the DISTATIS and pvclust libraries from an R package. Finally, the secondary structure consensus was modeled by Mfold, and a CBC analysis was obtained to complement the species delimitation using 4Sale. The phylogenetic tree results showed delimited monophyletic clades in Tulasnella spp., where all 142 Tulasnella sequences were divided into two main clades A and B and assigned to seven species (T. asymmetrica, T. andina, T. eichleriana ECU6, T. eichleriana ECU4 T. pinicola, T. violea), supported by bootstrap values from 72% to 100%. From the 2D secondary structure alignment, three types of consensus models with helices and loops were obtained. Thus, T. albida belongs to type I; T. eichleriana, T. tomaculum, and T. violea belong to type II; and T. asymmetrica, T. andina, T. pinicola, and T. spp. (GER) belong to type III; each type contains four to six domains, with nine CBCs among these that corroborate different species.

DETERMINING THE MORPHOLOGICAL CLASS OF A WORD DURING THE AUTOMATIC NATURAL LANGUAGE PROCESSING

The article considers a mandatory component of the linguistic provision of any system of automatic natural language processing, i.e. automatic morphological analysis, the tasks of which include: determining for each text unit its place in the morphological system of the corresponding language; identification of word forms of the lexeme. As a result of automatic morphological analysis, each word form of the text is assigned a tag for the part of speech and the meaning of the grammatical categories (gender, number, case, aspect, tense, person, etc.). The nature of this information, its volume, and the methods used to establish morphological information depend on the purpose of the research, within which automatic analysis is carried out with the focus on the nature of the analyzed texts. Morphological analysis is present at all stages of text analysis, because neither morphemic, nor syntactic, nor semantic analysis can be performed without parts-of-speech tagging. With automatic syntactic analysis, only if lexical-grammatical and grammatical information is available for each word form, it is possible to syntactically bind word forms in a sentence. Morphological features of text units further become a tool for researching the relationship between vocabulary and grammar and the use in speech; between paradigmatics (in the aspect of consideration of case forms of declinable words) and syntagmatics (in the aspect of linear relationships of words, text coherence).
 The article examines the difficulties that prevent unifying the process of tagging text units, namely lexical-grammatical homonymy, ambiguity of grammatical forms, polysemy. The study considers approaches to resolving morphological ambiguity based on the context analysis of the ambiguous word, which can be divided into statistical and rule-based. Rules can be compiled manually or derived from marked-up corpora. Statistical methods are based on quantitative indicators in large labelled corpora. Morphological ambiguity resolution methods are usually applied after primary tagging, which is usually done using dictionaries.
 The article also provides a morphemic analysis algorithm for automatic morphological analysis.

Online Assessment of Parafoveal Morphological Processing/Awareness during Reading among Chinese and Korean Adults

ABSTRACT Purpose The present study tested parafoveal morphological processing during sentence reading with two eye-tracking experiments, making use of an implicit measurement of morphological awareness. In Chinese and Korean, each character form typically corresponds to multiple mental lexicons, leading to morphological ambiguity. Method Using the gaze-contingent boundary paradigm, we manipulated the relation between the homographic parafoveal preview morphemes and the target words in Chinese and Korean, respectively, in two experiments. We tested 57 Chinese and 45 Korean university students. Together with baseline conditions in which the previews were either identical or unrelated to the target, we had two critical conditions in which the homographs shared/did not share the same morphemic meaning (i.e., same morpheme/different morpheme) with the target morpheme. Results Across the two experiments, the differences between the same and different morpheme conditions in a number of eye movement indices were significant, consistently showing that appropriate morpho-semantic information facilitates lexical processing. The different-morpheme previews facilitated the target word processing in Chinese but not in Korean reading. Conclusion These findings suggest that morphemic meanings are activated early on during word recognition in Chinese, a logographic orthography, and Korean Hangul, a phonologically transparent writing system, before the word is fixated upon.

Molecular Identification of Ribbon Fish (Eupleurogrammus Sp.) Using Partial Sequence of Mitochondrial COI Gene

Dry fish is considered as a delicacy in the menu of many people of Bangladesh. The most economically important marine and freshwater dried fishes are ribbon fish, bombay duck, olive barb, pomfret, shrimp, etc. In this study, fresh ribbon fish sample was collected from Cox's Bazar and morphologically identified as ribbon fish. The collected fish was confirmed through a molecular technique using mitochondrial COI gene (cytochrome c oxidase subunit I) to avoid morphological ambiguity, which is first reported data from Bangladesh. Partial sequence of this COI gene was amplified using a genus specific universal primer set. The target nucleotide sequence of COI gene was determined successfully with 616 bp length and the ribbon fish was identified as Eupleurogrammus sp. Within the amplified region GC and AT content were 45.5% and 54.5%, respectively. 16.88% interspecific polymorphism was observed when compared with other species under genus Eupleurogrammus collected from Gen Bank database. This sequence will be used as molecular bar code for authentic identification of Eupleurogrammus sp. at genus level. Bangladesh J. Zool. 50 (2): 231-238, 2022

Underwater Holothurian Target-Detection Algorithm Based on Improved CenterNet and Scene Feature Fusion.

Aiming at the common problems, such as noise pollution, low contrast, and color distortion in underwater images, and the characteristics of holothurian recognition, such as morphological ambiguity, high similarity with the background, and coexistence of special ecological scenes, this paper proposes an underwater holothurian target-detection algorithm (FA-CenterNet), based on improved CenterNet and scene feature fusion. First, to reduce the model’s occupancy of embedded device resources, we use EfficientNet-B3 as the backbone network to reduce the model’s Params and FLOPs. At the same time, EfficientNet-B3 increases the depth and width of the model, which improves the accuracy of the model. Then, we design an effective FPT (feature pyramid transformer) combination module to fully focus and mine the information on holothurian ecological scenarios of different scales and spaces (e.g., holothurian spines, reefs, and waterweeds are often present in the same scenario as holothurians). The co-existing scene information can be used as auxiliary features to detect holothurians, which can improve the detection ability of fuzzy and small-sized holothurians. Finally, we add the AFF module to realize the deep fusion of the shallow-detail and high-level semantic features of holothurians. The results show that the method presented in this paper yields better results on the 2020 CURPC underwater target-detection image dataset with an AP50 of 83.43%, Params of 15.90 M, and FLOPs of 25.12 G compared to other methods. In the underwater holothurian-detection task, this method improves the accuracy of detecting holothurians with fuzzy features, a small size, and dense scene. It also achieves a good balance between detection accuracy, Params, and FLOPs, and is suitable for underwater holothurian detection in most situations.

Morphometrics as a Complementary Tool in the Differentiation of Two Cosmopolitan Flea Species: Ctenocephalides felis and Ctenocephalides canis.

Simple SummaryMembers of Siphonaptera are commonly known as fleas. With more than 2500 species described worldwide, they constitute one of the most important parasites in our environment. The cat flea, Ctenocephalides felis, and the dog flea, Ctenocephalides canis, can also affect humans and represent a potential danger for the transmission of pathogens. Despite being two of the most frequently studied species, the classification and taxonomic diversity of these fleas is controversial. Variations in their morphological characteristics frequently hinder their correct identification and give rise to several uncertainties. To provide further information on the identification of these flea species, a geometric morphometrics analysis was conducted. This technique assisted in differentiating between specimens of both species, demonstrating that it can provide useful complementary data and new insights for the classification of flea species, especially when molecular biology techniques are not affordable or available.Fleas (Siphonaptera) are one of the most important ectoparasites that represent a potential danger for the transmission of pathogens in our environment. The cat flea, Ctenocephalides felis (Bouché, 1835), and the dog flea, Ctenocephalides canis (Curtis, 1826) are among the most prevalent and most frequently studied species throughout the world. However, the variations observed in their morphological characteristics complicate their correct identification, especially when there is a lack of access to the equipment and funds required to carry out molecular biology techniques. With the objective to provide an additional tool to help in the differentiation of Ctenocephalides species, a principal component analysis was carried out for the first time in the present work on populations of C. felis and C. canis from countries in three continents, namely Spain (Europe), South Africa (Africa) and Iran (Asia). The factor maps assisted in the differentiation of both species and the detection of differences in overall size, although morphological ambiguity prevented the delimitation in populations of the same species. Thus, morphometrics represents a complementary tool to other traditional and modern techniques, with great potential to assist in the differentiation of fleas, particularly species that have historically been difficult to identify.

A rapid, simple, and reliable assay to authenticate Peruvian kiwicha (A. caudatus) for food applications

Amaranth has acquired great economic impact as functional food, with species originating from Mexico dominating global trade. In contrast, the Peruvian A. caudatus (kiwicha) has been vastly neglected, although it is endowed with very promising nutritive traits. Morphological plasticity and taxonomic ambiguities render authentication of Amaranth difficult, such that the identity of commercial samples is often unclear. To safeguard the authenticity of kiwicha and, thus, consumer safety, we characterised a germplasm collection of 84 Amaranth accessions on both, the morphological and the genetic level. We show that kiwicha can be delineated phenotypically from other species by its late flowering, taller posture, and lower grain yields. Instead, flower and seed color, often used as proxy for identity, do not qualify as taxonomic markers. Using the plastidic barcoding marker psbA-trnH igs we were able to identify a specific Single Nucleotide Polymorphism (SNP) that separated kiwicha from all other species of Amaranth. This allowed us to develop a sequencing-free authentication assay using an Amplified Refractory Mutation System (ARMS) strategy. As a result kiwicha in commercial samples can be authenticated by a single duplex-PCR yielding a diagnostic side band reporting A. caudatus against all other species of Amaranthus. This fingerprinting assay will help to develop the nutritive potential of kiwicha and to safeguard seed material for A. caudatus against adulteration by the far more prevalent species from Mexico.

Genomics and ecological modelling clarify species integrity in a confusing group of butterflies.

Recent advances in both genomics and ecological modelling present new, multidisciplinary opportunities for resolving species boundaries and understanding the mechanisms that maintain their integrity in regions of contact. Here, we use a combination of high-throughput DNA sequencing and ecological niche modelling to resolve species boundaries and niche divergence within the Speyeria atlantis-hesperis (Lepidoptera: Nymphalidae) complex, a confusing group of North American butterflies. This complex is notorious for its muddled species delimitations, morphological ambiguity, and extensive mitonuclear discordance. Our admixture and multispecies coalescent-based analyses of single nucleotide polymorphisms identified substantial divergences between S. atlantis and S. hesperis in areas of contact, as well as between distinct northern and southern lineages within S. hesperis. Our results also provide evidence of past introgression relating to another species, S. zerene, which previous work has shown to be more distantly related to the S. atlantis-hesperis complex. We then used ecological models to predict habitat suitability for each of the three recovered genomic lineages in the S. atlantis-hesperis complex and assessed their pairwise niche divergence. These analyses resolved that these three lineages are significantly diverged in their respective niches and are not separated by discontinuities in suitable habitat that might present barriers to gene flow. We therefore infer that ecologically-mediated selection resulting in disparate habitat associations is a principal mechanism reinforcing their genomic integrity. Overall, our results unambiguously support significant evolutionary and ecological divergence between the northern and southern lineages of S. hesperis, sufficient to recognize the southern evolutionary lineage as a distinct species, called S. nausicaa based on taxonomic priority.

COTA 2.0: an Automatic Corrector of Tunisian Arabic Social Media Texts

In written text, orthographic noise is a common concern for NLP, especially when operating social network comments and raw documents. This is mainly due to its orthographic conventions and morphological ambiguity. We propose to automatically normalize the social media dialect corpora by following CODA-TUN, the Conventional Orthography for Tunisian Arabic (TA). The existing system developed for TA <<COTA Orthography 1.0>> is not able to handle all forms of TA. Therefore, we propose to extend its rules and lexicons to address the peculiarities of social media dialect. In certain words, the COTA Orthography 1.0 system provides the user with several correction possibilities. Therefore, in the new version, we incorporated a trigram language model to automatically select the right correction. Our results show that the system can reduce transcription errors by 95.72%.

Analysis of the mitochondrial genome of the Indian darter, Anhinga melanogaster, suggests a species status taxonomic rank.

Anhinga melanogaster is a carnivorous water bird native to many Asian countries. A. melanogaster is part of the Old World clade of darters. There is currently significant debate about the organization of the Old World clade due to morphological and genetic ambiguities. It is essential to establish the taxonomic status of A. melanogaster because it was recently listed by the International Union for Conservation of Nature (IUCN) as a near threatened species. The present study utilized a comprehensive molecular approach of the complete mitogenome of A. melanogaster to resolve its taxonomic status within the genus Anhinga. The mitogenome of A. melanogaster comprised of 13 protein-coding genes, 22 tRNA genes, 2 rRNA genes and a control region. A partially duplicated cytochrome b gene and control region were also present. Duplicated mitogenomic segments and phylogenetic analyses suggest that A. melanogaster, A. novaehollandiae, A. rufa and A. anhinga should be considered distinct species within the Old World clade of darters. The present study provides new insights into the mitogenome features of A. melanogaster and its evolutionary relationship within the genus, Anhinga.

Boundaries and hybridization in a secondary contact zone between freshwater mussel species (Family:Unionidae).

Correct species identification and delineation are crucial for effective conservation and management. However, species delineation can be problematic in the presence of morphological ambiguities due to phenotypic plasticity, convergence, and/or interspecific hybridization. Here, we investigated the degree of hybridization between two closely related freshwater mussel species [Bivalvia: Unionidae; Lampsilis siliquoidea (Barnes) and L. radiata (Gmelin)] that present intermediate forms in areas of sympatry. Unionids have a distinct form of mitochondrial DNA (mtDNA) inheritance, termed doubly uniparental inheritance (DUI) where female mtDNA (F-type) is transmitted to all progeny but male mtDNA (M-type) is mostly inherited by the males resulting in mostly homoplasmic females and heteroplasmic males. An individual was identified as hybrid when F-type and M-type mtDNA of the two different species were found in the same individual. Twelve out of 116 sequenced males were identified as hybrids indicating that these species hybridize where their geographic range overlaps in the lower Great Lakes and St. Lawrence basins. Microsatellite analyses further support the occurrence of hybridization but at a larger spatial scale than indicated by the mitochondrial analyses. We also found that strong within-species population genetic structure affects the detection of purebred individuals overestimating the number of hybrids. Given the large geographic scale and proportion of hybrids found in this study, natural hybridization and introgression need to be considered when implementing local biodiversity inventories, identifying waterbodies as source of organisms for relocation and restoration projects and when setting appropriate conservation policies.

Ambiguous Birds: Ideas about Bats on Flores Island and Elsewhere

Drawing on previous publications by the author, this article brings together information on folk classification and symbolic values of bats among the Nage people of the Indonesian island of Flores. This information is supplemented by new data from more recent field-based ethnobiological research in Nage and other parts of Flores, and is analyzed comparatively with reference to ideas about Chiropterans from other parts of the world. The way Nage and other Flores Islanders treat bats may appear cross-culturally unusual, but their ideas are shown to fit within a range of ways humans think about these remarkable creatures. In a more general vein, attention is given to the widely recognized morphological and behavioral ambiguity of bats and the variable extent to which this ambiguity affects their representation—both in folk zoological classification (or ethnotaxonomy) and symbolic thought (including taboo, spiritual belief, myth, and metaphor). A comparative analysis also demonstrates how, by contrast to the stereotypical view of bats as embodiments of evil in European thought, both Westerners and non-Westerners can represent bats positively, and that even where a generally negative view prevails, bats can possess a positive value contextually.

Genetic barcoding of museum eggshell improves data integrity of avian biological collections

Natural history collections are often plagued by missing or inaccurate metadata for collection items, particularly for specimens that are difficult to verify or rare. Avian eggshell in particular can be challenging to identify due to extensive morphological ambiguity among taxa. Species identifications can be improved using DNA extracted from museum eggshell; however, the suitability of current methods for use on small museum eggshell specimens has not been rigorously tested, hindering uptake. In this study, we compare three sampling methodologies to genetically identify 45 data-poor eggshell specimens, including a putatively extinct bird’s egg. Using an optimised drilling technique to retrieve eggshell powder, we demonstrate that sufficient DNA for molecular identification can be obtained from even the tiniest eggshells without significant alteration to the specimen’s appearance or integrity. This method proved superior to swabbing the external surface or sampling the interior; however, we also show that these methods can be viable alternatives. We then applied our drilling method to confirm that a purported clutch of Paradise Parrot eggs collected 40 years after the species’ accepted extinction date were falsely identified, laying to rest a 53-year-old ornithological controversy. Thus, even the smallest museum eggshells can offer new insights into old questions.

Prosodic Disambiguation of Morphological Ambiguities in Turkish.

This study investigates the production and processing of lexical prosody in morphological ambiguities in Turkish. Native speakers of Turkish took part in two read-aloud and two lexical decision experiments. The results showed that in speaking, for both genuine and pseudo words that contrasted in stress, participants changed the fundamental frequency (F0) and intensity to disambiguate; and they changed duration (but not F0 or intensity) to disambiguate words and pseudo-words that did not contrast in stress. In listening, the participants were sensitive to the prosodic (mis)match in stress-contrasting pairs, but not to durational (mis)match presumably because the durational differences between the comparison pairs were shorter than perceivable. The findings show that Turkish speakers use prosody to disambiguate morphologically ambiguous word pairs and that they are sensitive to prosodic cues (at least to those used in stress contrast) when they hear them. Their behavior for pseudo-words suggests that they do so not on the basis of individual word knowledge but productively. The comparison pairs in the current study were segmentally identical, allowing us to attribute the observed prosodic variation only to the morpho-syntactic structure of the ambiguous pairs.

ON THE IDENTITY OF HOG-NOSED PIT-VIPERS FROM WESTERN PANAMA: A REVIEW OF SPECIMENS OF PORTHIDIUM LANSBERGII (SCHLEGEL, 1841) IN LOWER CENTRAL AMERICA.

Porthidium lansbergii is a relatively abundant pit viper in semiarid environments from eastern Panama, through the Caribbean plains and Magdalena Valley in Colombia to northeastern Venezuela. Like other members of this genus, P. lansbergii exhibits great variation in scutellation and other morphological characters, a situation that has complicated the taxonomy and identification of populations assigned to the species. In Lower Central America, P. lansbergii is known to inhabit seasonally-dry environments of the Pacific slopes of western Panama. Here, we aimed to clarify the taxonomic status of some enigmatic specimens collected in western Panama, with morphological ambiguity, resembling P. lansbergii. We used the mitochondrial marker cytochrome oxidase b to perform a Bayesian phylogenetic analysis, to evaluate the affinities ofthese specimens with P. lansbergii individuals from central and eastern Panama, and Venezuela. We also analyzed meristic morphological characters to discriminate among populations of P. lansbergii in Panama, including other species of the Porthidium genus. Our analyses indicate that the enigmatic individuals do not differ from others individuals identified as P. lansbergii, thus forming a monophyletic group. We conclude that P. lansbergii has a more extended range than currently recognized including the western Pacific in Panama.

Learning Word-vector Quantization

We introduced a new classifier named Learning Word-vector Quantization (LWQ) to solve morphological ambiguities in Turkish, which is an agglutinative language. First, a new and morphologically annotated corpus, and then its datasets are prepared with a series of processes. According to datasets, LWQ finds optimal word-vectors positions by moving them in the Euclidean space. LWQ does morphological disambiguation in two steps: First, it defines all solution candidates of an ambiguous word using a morphological analyzer; second, it chooses the best candidate according to its total distances to neighbor words that are not ambiguous. To show LWQ's performance, we have conducted many tests on the corpus by considering the consistency of classification. In the experiments, we achieve 98.4% correct classification ratio to choose correct parse output, which is an excellent level for the literature.

The efficiency of universal mitochondrial DNA barcodes for species discrimination of Pomacea canaliculata and Pomacea maculata.

Invasive apple snails, Pomacea canaliculata and P. maculata, have a widespread distribution globally and are regarded as devastating pests of agricultural wetlands. The two species are morphologically similar, which hinders species identification via morphological approaches and species-specific management efforts. Advances in molecular genetics may contribute effective diagnostic tools to potentially resolve morphological ambiguity. DNA barcoding has revolutionized the field of taxonomy by providing an alternative, simple approach for species discrimination, where short sections of DNA, the cytochrome c oxidase subunit I (COI) gene in particular, are used as ‘barcodes’ to delineate species boundaries. In our study, we aimed to assess the effectiveness of two mitochondrial markers, the COI and 16S ribosomal deoxyribonucleic acid (16S rDNA) markers for DNA barcoding of P. canaliculata and P. maculata. The COI and 16S rDNA sequences of 40 Pomacea specimens collected from six localities in Peninsular Malaysia were analyzed to assess their barcoding performance using phylogenetic methods and distance-based assessments. The results confirmed both markers were suitable for barcoding P. canaliculata and P. maculata. The phylogenies of the COI and 16S rDNA markers demonstrated species-specific monophyly and were largely congruent with the exception of one individual. The COI marker exhibited a larger barcoding gap (6.06–6.58%) than the 16S rDNA marker (1.54%); however, the magnitude of barcoding gap generated within the barcoding region of the 16S rDNA marker (12-fold) was bigger than the COI counterpart (approximately 9-fold). Both markers were generally successful in identifying P. canaliculata and P. maculata in the similarity-based DNA identifications. The COI + 16S rDNA concatenated dataset successfully recovered monophylies of P. canaliculata and P. maculata but concatenation did not improve individual datasets in distance-based analyses. Overall, although both markers were successful for the identification of apple snails, the COI molecular marker is a better barcoding marker and could be utilized in various population genetic studies of P. canaliculata and P. maculata.