Interrogation of earthworm (Clitellata: Haplotaxida) taxonomy and the DNA sequence database

The identity and validity of the freshwater worm Dero indica (Clitellata: Naididae; Naidinae) has been debated, and it has been suggested that it is likely to be identical with D. digitata. In this study we combine a newly generated COI sequence of D. indica with available sequences from GenBank, to estimate the phylogeny of Dero using both Bayesian Inference and Maximum Likelihood. The trees show that D. indica is well separated from D. digitata, instead it is closest to D. vaga, but with low support. Furthermore, the analyses confirm the close relationship between Dero and Branchiodrilus found in previous studies, and indicates the presence of cryptic species in D. furcata and D. digitata.

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On the identity and phylogenetic position of Dero indica (Clitellata: Naididae)

Taxonomic classification of earthworms based on anatomical features has created several challenges for systematics and population genetics. This study examines the application of molecular markers, in particular mitochondrial cytochrome oxidase (COI), to facilitate discrimination of closely related earthworm species. Molecular markers have also provided insights into population genetics by aiding assessment of genetic diversity, lineage sorting, and genealogical distributions of populations for several species. Phylogeography—a study that evaluates the geographical distribution of these genealogical lineages and the role of historical processes in shaping their distribution—has also provided insights into ecology and biodiversity. Such studies are also essential to understand the distribution patterns of invasive earthworm species that have been introduced in non-native ecosystems globally. The negative consequences of these invasions on native species include competition for food resources and altered ecosystems. We anticipate that molecular markers such as COI and DNA barcoding offer potential solutions to disentangling taxonomic impediments in earthworms and advancing their systematics and population genetics. 

/pdf/disentangling-earthworm-taxonomic-stumbling-blocks-using-1r5cr6doi6.pdf

Disentangling earthworm taxonomic stumbling blocks using molecular markers

DNA barcoding and genetic variability of earthworms (Clitellata: Oligochaeta) with new records from Mizoram, India

— Earthworms are considered as biological indicators of soil fertility forms the major macro fauna of soil. DNA tag are done to identify individuals belonging to the same species, as well as to distinguish between individuals from different species. In the present work, the earthworm fauna was investigated from three Taluks namely, Somvarpet, Virajpet and Madikeri of Coorg, a district situated in the south western part of Karnataka, India. This is the first scientific report on the earthworm species of Coorg and the physio-chemical properties of their soil. The physio-chemical characteristics of the soil were examined and DNA barcoding technology was used to identify the taxonomic status of earthworms. A total of 38 earthworm samples were collected, 30 of which were amplified using mitochondrial Cytochrome Oxidase subunit1 (CO1) gene specific primers. The sequencing data was deposited into Genbank and assigned accession numbers (30 Accessions). The maximum likelihood technique was used to create the phylogenetic tree. Kimura's two-parameter model was used to calculate pairwise genetic distance. DNA barcoding results showed that Pontoscolex corethrurus was the most common earthworm species in Coorg. Progizzardus varadiamensis, Glyphidrilus annandalei, Amythas sp., Metaphire megascolidioides, Dichogaster bolaui and Acanthodrilidae sp were also observed. From the findings it is observed that the mean pH of Coorg soil was found to be 6.2 with an electrical conductivity of 0.28 dS/m. Coorg soil contains a moderate level of Organic Carbon (O.C) content with an average of 1.74%. Thus, the study included extensive descriptions of earthworm species, as well as their DNA barcodes and the physio chemical characteristics of their habitat, which help with future species identification. The blast annotation shows 100% identity with Polypheretima elongate with 9e-63 E-value and 100% query coverage according to the nucleotide homology The blast annotation shows 87.10% identity with Metaphire megascolidioides with 7e-72 E-value and 98% query coverage according to the nucleotide homology. blast annotation

/pdf/dna-barcoding-of-earthworms-of-coorg-region-of-karnataka-1f6pdgjv.pdf

DNA Barcoding of Earthworms of Coorg Region of Karnataka, India and Study of Their Physio-Chemical Habitat

/pdf/study-on-the-amynthas-kinberg-1867-earthworm-megascolecidae-jain371l1p.pdf

Study on the Amynthas (Kinberg, 1867) earthworm (Megascolecidae: Oligochaeta) diversity through DNA barcoding from Northeast India

/pdf/diversity-and-new-records-of-earthworms-in-arunachal-pradesh-4nfajpcevf.pdf

Diversity and New Records of Earthworms in Arunachal Pradesh, Northeast India

Oligochaeta is a class of segmented worms under the phylum Annelida that are characterised by the presence of tiny setae in each body segment. Earthworms are the main members, consisting of approximately 6200 species. Their ecological importance is well known as they are the major soil macro-fauna; Aristotle had named them as “the intestines of soil”. Classification of earthworms is a controversial issue since the introduction of modern taxonomical system on earthworm by Michaelsen in 1921. This is mainly because conventional identification using morphological and anatomical characters are complicated and confusing. The key diagnostic features such as the position and structure of the reproductive organs, clitellum and the associated tubercular pubertatis are not always reliable, particularly in different developmental stages, especially when the available specimens are the juveniles. DNA barcoding has offered a potential solution, even at the levels of identifying the juveniles or cocoons. Several genes including mitochondrial cytochrome-c oxidase I, 16S, 18S and 28S ribosomal RNAs, and protein-coding histone H3 genes have been introduced in the taxonomy and phylogeny of earthworm. It is anticipated that DNA barcoding will help conflicting taxonomy and further exploration of species diversity in India.

/pdf/oligochaete-taxonomy-the-rise-of-earthworm-dna-barcode-in-gzw350ccsk.pdf

C. Zothansanga

Papers

Study on the Amynthas (Kinberg, 1867) earthworm (Megascolecidae: Oligochaeta) diversity through DNA barcoding from Northeast India

Diversity and New Records of Earthworms in Arunachal Pradesh, Northeast India

Oligochaete taxonomy – The rise of earthworm DNA barcode in India