Class Monogenea Van Beneden, 1858
Order Dactylogyridea Bychowsky, 1937
Family Dactylogyridae Bychowsky, 1933
Genus Dactylogyrus Diesing, 1850
Dactylogyrus kolodynensis sp. n.
Morphological characterisation (Figures 1 and 2)
[Based on 15 specimens]: With characters of the genus as defined by Diesing (1850). Body fusiform 307 (290-312; n=5) long; greatest width 90 (85-95; n=5) near midlength. Single pairs of (dorsal) anchors 27 (24-32; n=8) long with elongated inner root 11 (9-13; n=9) long; short outer root 4 (2-6; n=8) long, curved shaft 20 (17-25; n=8) long, recurved point 11 (9-13; n=8) long and extending the past level of the tip of inner root. Single (dorsal) bar 20 (17-23; n=10) long, 5 (3-7; n=10) wide, rod-shaped with a short posteromedial expansion, and rounded lateral ends posteriorly directed. Seven pairs of hooks, similar in shape but dissimilar in size, each with a delicate point, depressed thumb (except 6th, which has upright thumb), shank comprised of 2 subunits (proximally expanded subunit), a pair of needles located near the hooks of pair 6, HF loop extending to near union of shank subunits; hook lengths: pair I, 19 (16-22; n=5) long, pair II, 18 (16-21; n=5) long, pair III, 20 (17-22;n=5) long, pair IV, 10 (7-12; n=5) long, pair V, 18 (16-21;n=5) long, pair VI, 19 (17-21; n=5) long, pair VII, 20 (17-22; n=5) long. Male copulatory organ comprised of a copulatory tube articulated to the base of a complex accessory piece by a thick ligament. Copulatory tube 85 (77-88; n=8) long, with a loose coil following a circular path of one complete clockwise ring, narrowing to delicate termination. Accessory piece 29 (26-32; n=10) long, complex, with lower and upper variable sheathes curving towards each other like claws; upper sheath longitudinally grooved to guide the distal end of copulatory tube. Vagina 35 (32-38; n=10) long, a sclerotized tube with a terminal flower-bud-shaped vaginal pore. Egg 66 (n=1) long, 46 (n=1) wide, operculate,
one short polar filament on adopercular end.
Sequencing of partial 28S rRNA gene of D. kolodynensis resulted in amplicons of the same length size (508 bp) and showed no intraspecific nucleotide variations between different individuals collected from two different localities examined here. The sequence of D. kolodynensis sp. n. was deposited in GenBank database (http://www.ncbi.nlm.nih.gov), accession number OL964059. A BLAST search revealed that this sequence did not match 100% to any of the known any available sequences in GenBank, confirming our initial morphological identification (Table 1).
The main diagnostic characters of the new species are: a copulatory tube that is a loose coil of one complete clockwise ring, a jaw-shaped accessory piece with variable sheathes enclosing and guiding the copulatory tube, and sclerotized vaginal tube with a terminal flower-bud-shaped vaginal pore.
Type host Osteobrama cotio (Hamilton, 1822) (Cypriniformes, Cyprinidae)
Type locality: River Kolodyne, Lawngtlai, Mizoram, India (22°35′15″N, 92°55′13″E)
Infection site: Gill lamellae
Additional locality: River Gomti, Lucknow, Uttar Pradesh, India (26°52′12″ N; 8°55′20″ E)
Infection parameters: 72.72% (eight out of 11 fishes) were infected from Lawngtlai (Mizoram) with intensity of 3–10 (mean = 5) parasites/ infected host; 70.83% (17 out of 24 fishes) were infected from Lucknow (Uttar Pradesh) with intensity of 4–9 (mean = 6) parasites/ infected host
Date of sampling: August 2021 to October 2021
Deposition of specimens: Holotype (xxxxxx) and Paratypes (xxxxxx) in Zoological Survey of India, Kolkata, India; Other paratypes (xxxxxx) in the helminthological collection of
the Department of Zoology, University of Lucknow, India.
Representative DNA sequence: 28S rRNA (508 bp), OL964059
ZooBank registration: The Life Science Identifier (LSID) for Dactylogyrus kolodynensis sp. n. is xxxxxxxxxxx.
Etymology: The species is named after the river “Kolodyne”, the type locality of the species, with the Latin suffix -ensis denoting a location.