Mazocraeoides dussumieri Mamaev, 1975

Sailaja, Bade, Shameem, Ummey & Madhavi, Rokkam, 2019, Four species of Mazocraeoides Price, 1936 (Monogenea: Mazocraeidae), including two new species from clupeiform fishes off Visakhapatnam coast, Bay of Bengal, Zootaxa 4608 (2), pp. 233-246 : 240-242

Mazocraeoides dussumieri Mamaev, 1975

( Figs. 14–17 )

Host: Dussumieria hasselti Bleeker (Clupeidae) .

Locality: Visakhapatnam coast, Bay of Bengal.

Site in host: Gills.

Specimens deposited: Zoological Survey of India, Kolkata, India. Voucher specimen 10441/1.

Prevalence and mean intensity: 51.45% and 1.92 worms per infected fish.

28SrDNA sequences: Genbank Accession No. KF306257 .

Description: (Measurements based on 7 specimens) Body elongate, 1458 (1312–1728) long, 278 (224–336) wide, haptoral region not well demarcated from body proper but four pairs of clamps are located on short peduncles in posterior quarter of body. Haptoral region embraces part of testis; anterior part of testis and ovary lie anterior to haptoral region. Haptoral region with paired pedunculate clamps appears like a fan. Clamps of equal size, 40.5 (40–44) in length, 38 (36–40) in width, first pair located at distance of 1132 (880–1280) from anterior end. Clamps closed type with short peduncles, clamp skeleton comprises of five sclerites- SAA, SAS, SMB, SMS and SL. Individual sclerites: SAA ‘arch- shaped’, SMB bilobed with wing like lateral extensions, SMS almost rectangular, SAS cup-like, SL ‘U-shaped’. Lappet small, 82 (64–96) x 57 (48–64), with two pairs of anchors and one pair of hooks. Outer pair of anchors large, 10.5 (10–11) in size with broad shaft, lateral blunt spur and curved blade. Inner pair of anchors smaller in size 5.5 (5 –6). Hooks very small, 3 in size, rod like without spur. Anterior end with one pair of suckers, 36 (28– 40) x 38.8 (32–44) in size. Pharynx oval, 31 (28–40) x 25 (20–32). Esophagus long, intestinal bifurcation at a distance of 171 (152–200) from anterior extremity. Intestinal ceca with lateral branches extend to level of last pair of clamps, tips of ceca closely associated but not confluent.

Genital pore median, at distance of 173 (152–196) from anterior end. Testis single, 240 (200–280) in size, consists of compact group of linearly arranged follicles, situated in posterior half of body, overlapped by cecal branches, not visible in most specimens. Genital complex small, at level of intestinal bifurcation point, 21 (20–24) long and 20 (16–24) wide, armed with one pair of lateral hooks and 10 smaller median hooks. Lateral hooks scoop-shaped, fairly large in size, median hooks with broad base and pointed tips, smaller in size, arranged in two semicircles above and below two lateral hooks.

Ovary large, tubular, 277 (228–360) x 43 (32–64), posterior half lies dextral to testis, anterior half pretesticular, anterior part represents germarium, posterior part filled with mature ova. Seminal receptacle, vagina not visible. Mehlis’s gland post- ovarian. Uterus narrow tube extends along median line, anterior to ovary, opens out anteriorly through genital pore. Vitellarium follicular, follicles densely distributed between level of intestinal bifurcation and posterior end of body. Vitelline ducts at level of ovary. Eggs not found.

Remarks: The present specimens agreed in many respects of their organization with M. dussumieri reported from Dussumieria elopsoides by Mamaev (1975) from South China Sea. The species is characterized by the presence of four pairs of pedunculate clamps and their distribution is confined to posterior third of body. Although the clamps were not embedded in the body proper, the clamp skeleton with its five sclerites is similar to that in other species of Mazocraeoides . The genital complex contained one pair of lateral and 10 median hooks. The organization of the genital complex including the total number of genital hooks, arrangement of hooks and shape of median hooks is similar to that of Mamaev’s form but differs in the shape of the lateral hooks which are curved and pointed inwards in Mamaev’s form whereas they are provided with a broad plate- like base and pointed tips in the present forms. The testis is located in the haptoral zone and the ovary is located in body proper in Mamaev’s forms as well as in the present form. In Mamaev’s form the ovary lies anterior to testis while the position of the ovary is dextral and anterior to the testis in the present form. Mamaev reported only two pairs of anchors on lappet; here two pairs of anchors are found and the very small rod- like hooks have probably been overlooked by Mamaev. The present specimens are slightly larger than those from South China Sea ([1312–1728] x [224–336] vs ([960–1300] x [200–240]).

Five species of Mazocraeoides have been recorded from Dussumieria spp. from Indian region including M. acutai Gupta and Krishna, 1978 ; M. dussumieriai Gupta and Krishna, 1978 ; M. gussevi Gupta and Masoodi, 1985 ; M. jairajpurii Gupta and Masoodi, 1985 and M. puriensis Gupta and Krishna, 1976 ( Table 1 ). All these species were included under the category of species inquirendae ( Williams 1988, Zhang et.al. (1998). However, a restudy of the organization of these species may prove that at least some of them are synonymous to M. dussumieri . At this stage it is difficult to comment on their synonymy because of the poor descriptions given for the various species mostly based on one individual specimen that often were highly distorted. The illustrations are also poor and lack details that are needed for specific identification.

Including the two new species, Mazocraeoides now contains fifteen valid species. The following key serves to differentiate the various species.

Key to species of Mazocraeoides 1

1. Clamps small, less than 30 µm in diameter................................................................. 2 Clamps fairly large, more than 30 µm in diameter........................................................... 7

2. Genital complex very large, prominent........................................................... M. prashadi Genital complex small, not very prominent................................................................ 3

3. Genital complex with 1 pair of lateral and 2 pairs of median hooks................................... M. gonialosae Genital complex with 1 pair of lateral and 5 pairs of median hooks.............................................. 4

4. Haptoral clamps confined to posterior third of body........................................... M. fusiformes n. sp. Haptoral clamps spread in posterior half of body............................................................ 5

5. Ovary pretesticular.......................................................................... M. jimeiensis Ovary lateral to testis.................................................................................. 6

6. Ovary tubular, folded...................................................................... M. dorosomatis Ovary oval, compact.................................................................... M. rotundus n. sp.

7. Posterior 2 pairs of clamps smaller than the anterior 2 pairs........................................ M. xijiangensis All the clamps are of equal size.......................................................................... 8

8. Median genital hooks 2 pairs............................................................................ 9 Median genital hooks 3 to 5 pairs........................................................................ 10

9. Anterior part of body long and extensile, clamps pedunculate...................................... M. makrodemas Body oval, anterior part not extensile, clamps not pedunculate......................................... M. australis

10. Median genital hooks 3 pairs................................................................ M. nematolosae Median genital hooks 5 pairs........................................................................... 11

11. Gonads located within the haptoral zone.................................................................. 12 Gonads located partly anterior to haptoral zone................................................... M. dussumieri

12. Clamps on short peduncles, project from lateral margins of body.................................. M. tennesseensis Clamps without peduncles, embedded in lateral margins of body........................................ M. georgei

1 Mazocraeoides bychowskyi Caballero & Caballero, 1976 and M. argentinensis Suriano, 1979 are not included in the key due to non-availability of literature.

Figures

FIGURES 14–17. Mazocraeoides dussumieri 14. Entire worm, ventral view; 15. Genital atrium, lateral view; 16. Clamp; 17. Anchors and hooks. Scale bars: Fig.14, 200µm; Figs.15–17, 10µm.