Podocotyle, Dujardin, 1845

Blend, Charles K., Dronen, Norman O. & Armstrong, Howard W., 2019, Occurrence of Podocotyle Dujardin, 1845 (Opecoelidae, Podocotylinae) in three species of deep-sea macrourids from the Gulf of Mexico and Caribbean Sea with an updated key to species and host-parasite checklist, Zootaxa 4638 (4), pp. 507-533 : 516

Podocotyle sp. 1

( Fig. 2 )

Synonyms: Podocotyle (Podocotyle) sp. n. #1 of Armstrong (1974), Bray (1995) & Blend (1996).

Host: Western Atlantic grenadier, Nezumia atlantica (Parr) (= Ventrifossa atlantica Parr ) ( Gadiformes : Macrouridae : Macrourinae ).

Locality: Northeastern Gulf of Mexico off Florida, 27°38’ N, 85°15’ W, depth = 637 m, 23/June/1971.

Site of infection: Intestine.

Prevalence: 1 of 21 (4.8%).

Intensity: only 1 worm.

Mean intensity: 1/1 = 1.00.

Relative density/abundance: 1/21 = 0.05.

Deposited Specimen: NHMUK 2019.4.12.22 (1 slide).

Records: 1. Armstrong (1974); 2. Bray (1995); 3. Blend (1996); 4. Present study.

Descriptions: 1, 4.

Description: [Based on 1 possibly senescent specimen with contracted forebody and tear along left margin of body at level of ventral sucker; stain appears faded and grainy in much of specimen. Measurements and proportions given in Table 2 .] With characteristics of genus. Body oval-elongate, rounded to somewhat truncate extremities, flattened dorsoventrally, widest in posterior 1/3 of body. Forebody contracted, 1/4 body length. Hindbody wider primarily than forebody, gradually widens in posterior 1/3 of body. Tegument smooth. Pre-oral lobe not observed. Oral sucker subspherical, subterminal, unspecialized. Ventral sucker prominent, unspecialized, muscular with thickwalled perimeter, transversely oval and wider than long, at junction of first and second 1/4 of body. Prepharynx absent. Pharynx muscular, oval, off center (rolled?) and overlapped by oral sucker. Esophagus contracted, short and straight. Intestinal bifurcation midway between oral and ventral suckers. Ceca long, moderately wide with consistent width throughout, terminate blindly near posterior extremity; left cecum slightly arcuate at posterior end.

Testes 2, median, tandem, contiguous, transversely elongate and appear broken up (senescent?) with inconspicuous margins, intercecal, post-equatorial in posterior 1/3 of body. Post-testicular region confined to posterior 1/6 of body. Cirrus pouch a slender, long, narrow tube with distinct wall, extends posteriorly to posterodextral margin of ventral sucker, passes anteriorly in a straight line dorsally over right side of ventral sucker to anterodextral margin of sucker, turns anterosinistrally to ventrally pass over left cecum to terminate near level of posterior pharynx and anterior esophagus. Seminal vesicle internal, bi-partite; proximal portion saccate, occupies only posterior 1/4 of cirrus pouch; distal portion tubular and occupies remaining anterior 3/4 of pouch. Pars prostatica and prostatic gland cells not observed but expected to be present with former located near distal end of cirrus pouch. Genital pore submedian (sinistral), pre-acetabular, at level of esophagus, midway between left margin and midline of worm. Genital atrium present.

Ovary 3-lobed, lobes inconspicuous, median, just post-equatorial in middle 1/3 of body, post-acetabular, contiguous to and immediately anterior to anterior testis, intercecal. Portions of proximal female system not observed; canalicular seminal receptacle and Laurer’s canal with dorsal opening expected. Vitelline reservoir large, submedian (dextral), sub-triangular in shape, immediately anterodextral to ovary. Path of oviduct not observed, but expected to arise anteriorly from ovary, receive both Laurer’s canal and main vitelline duct, then enter oötype which is itself expected to be anterior to ovary and surrounded by Mehlis’ gland cells. Uterus conspicuous, intercecal, wider proximally, extends posterior to ovary; proximal portion proceeds anteriorly from level of anterior testis, passes dorsally and narrows over center of ventral sucker; distal portion runs parallel and to left side of distal portion of cirrus pouch to enter genital atrium. Metraterm not observed. Vitelline follicles moderate in size, dense, round to globular to oblong in shape, ventral and lateral to ceca but not dorsal, extend longitudinally in 2 uninterrupted lateral bands from near posterior extremity anteriorly up to level of posterior margin of ventral sucker (right band to posterior margin of sucker; left band short of sucker by 52 μm), overlap lateral margins of posterior testis, not confluent in pre-ovar- ian region, in space between ovary and anterior testis, in inter-testicular region and in post-testicular region. Eggs collapsed and/or crenulated, small, operculate, amber, non-embryonated, non-filamented, numerous with nib on one pole; bloated / inflated eggs also observed.

Excretory bladder I-shaped/tubular, extends to posterior testis, conspicuous and separates vitelline follicles at midline of worm. Excretory pore terminal.

Figures

FIGURES 1–2. Podocotyle pearsei Manter, 1934 from the Vaillant’s grenadier, Bathygadus melanobranchus, and Podocotyle sp. 1 from the Western Atlantic grenadier, Nezumia atlantica. 1. P. pearsei, whole specimen, ventral view. 2. Podocotyle sp. 1, whole specimen, dorsal view (redrawn from Armstrong 1974, Fig. 19; uterus drawn dorsal to ovary for ease of observation). Abbreviations: AT, anterior testis; C, cecum; CP, cirrus pouch; E, esophagus; EG, egg; EV, excretory vesicle; GP, genital pore; O, ovary; OS, oral sucker; P, pharynx; PG, pharyngeal gland cells; PT, posterior testis; SR, seminal receptacle; SV, seminal vesicle; T, testes; U, uterus; V, vitelline follicles; VR, vitelline reservoir; VS, ventral sucker.