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 : 517-521

Podocotyle sp. 2

( Fig. 3 )

Synonyms: Podocotyle (Podocotyle) sp. n. #2 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, 28°22’ N, 86°31’ W, depth = 710 m, 26/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 2019.4.12.23 (1 slide).

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

Descriptions: 1, 4.

Description: [Based on 1 specimen wherein stain appears slightly faded and a tiny tear is present in posterodextral region of worm. Measurements and proportions given in Table 2 .] With characteristics of genus. Body ovalelongate, rounded to slightly pointed extremities, flattened dorsoventrally, margins parallel and widest in middle 1/3 of body. Forebody slightly attenuated to rounded extremity, 1/4 body length. Hindbody wider than forebody, with parallel margins until posterior 1/4 of body where it attenuates to a more pointed extremity. Tegument smooth. Pre-oral lobe not observed. Oral sucker subspherical, subterminal, unspecialized. Ventral sucker prominent, unspecialized with wide muscular perimeter, somewhat protuberant, transversely oval and wider than long, at junction of first and second 1/4 of body. Prepharynx not observed. Pharynx muscular, round, large. Esophagus contracted, thick-walled and sinuous. Intestinal bifurcation ventrally overlapped by anterior margin of ventral sucker. Ceca conspicuous, thin-walled, voluminous, with near consistent width throughout until posterior end where ceca narrow and terminate blindly at posterior extremity; left cecum more narrowed at posterior end than right cecum.

Testes 2, median, tandem, contiguous, transversely oval to globular, intercecal, post-equatorial near junction of middle and posterior 1/3 of body. Post-testicular region occupies posterior 1/4 of body. Cirrus pouch clavate with indistinct wall, extends posterodextrally over right side of ventral sucker to level of posterior edge of sucker. Seminal vesicle internal, bi-partite; proximal portion saccate, occupies posterodextral portion of cirrus pouch; distal portion tubular and narrows towards anterior end of pouch. Pars prostatica inconspicuous; ejaculatory duct long; prostatic gland cells distributed throughout cirrus pouch with dense numbers along left margin of pouch. Genital pore submedian (sinistral), ventrally overlapped by puckered anterior margin of ventral sucker, at level of lower esophagus, midway between left margin and midline of worm. Genital atrium present.

Ovary 3-lobed, lobes inconspicuous, sub-triangular in shape, median, equatorial in middle 1/3 of body, postacetabular, contiguous to and immediately anterior to anterior testis, intercecal. Vitelline reservoir conspicuous, median to just submedian (sinistral), sub-triangular, contiguous with anterodorsal edge of ovary. Transverse vitelline ducts run dorsal to and parallel along anterior margin of ovary, extend laterally to medial walls of ceca. Canalicular seminal receptacle oval, pre-ovarian, dextral to vitelline reservoir and along midline of worm, 74 long × 44 wide. Laurer’s canal runs between ovary and vitelline reservoir, opens dorsally. Oviduct arises from anterior-most lobe of ovary (large ova seen in anterior lobe), receives both Laurer’s canal and main vitelline duct, then enters oötype anterior to ovary; large Mehlis’ gland cells present. Uterus inconspicuous, narrow, intercecal, extends posteriorly to mid-level of ovary and runs anterodorsally over ventral sucker and parallel to and along left side of distal portion of cirrus pouch before it enters genital atrium. Metraterm not observed. Vitelline fields follicular, large, circular to more elongate in shape, extend longitudinally in uninterrupted lateral bands (small gap to right of ventral sucker near body margin) from near posterior extremity anteriorly to level of anterior margin of ventral sucker (right band extends to anterior margin of sucker; left band extends anteriorly only to posterior margin of sucker); dorsal follicles along medial and lateral margins of ceca only, ventral follicles confluent over ceca, overlap lateral margins of testes, not confluent in but encroach into pre-ovarian region, in space between ovary and anterior testis, and in inter-testicular region; follicles in post-testicular region are not confluent dorsally but confluent ventrally in anteriormost area of this region. Eggs few (only 3 observed), collapsed and/or crenulated, large, operculate, amber, non-embryonated, non-filamented with nib on one pole.

Excretory bladder I-shaped/tubular, wide, very conspicuous, extends to posterior border of posterior testis. Excretory pore terminal.

Figures

FIGURES 3–4. Podocotyle sp. 2 from the Western Atlantic grenadier, Nezumia atlantica, and Podocotyle sp. 3 from Bathygadus favosus. 3. Podocotyle sp. 2, whole specimen, dorsal view (redrawn from Armstrong 1974, Fig. 20). 4. Podocotyle sp. 3, whole specimen, ventral view. Abbreviations: AT, anterior testis; C, cecum; CP, cirrus pouch; E, egg; ES, esophagus; EV, excretory vesicle; GP, genital pore; O, ovary; OS, oral sucker; P, pharynx; PT, posterior testis; SR, seminal receptacle; SV, seminal vesicle; U, uterus; V, vitelline follicles; VR, vitelline reservoir; VS, ventral sucker.

Tables

TABLE 2. Dimensions of Podocotyle pearsei Manter, 1934 from Bathygadus melanobranchus Vaillant and unidentified Podocotyle spp. from Bathygadus favosus Goode & Bean and Nezumia atlantica (Parr) (Gadiformes: Macrouridae) collected from the Gulf of Mexico and Caribbean Sea off Colombia.

Parasite	Podocotyle pearsei Manter, 1934	Podocotyle pearsei Manter, 1934	Podocotyle sp. 1	Podocotyle sp. 2	Podocotyle sp. 3
n =	1	11	1	1	1
Type designation & fixation	Voucher; cold-fixed 1	Vouchers; cold-fixed 2	Voucher; alive/heat- fixed	Voucher; alive/heat- fixed	Voucher; cold-fixed
Host	B. melanobranchus (Macrouridae)	B. melanobranchus (Macrouridae)	N. atlantica (Macrouridae)	N. atlantica (Macrouridae)	B. favosus (Macrouridae)
Locality	NE Gulf of Mexico	Western Gulf of Mexico	NE Gulf of Mexico	NE Gulf of Mexico	Caribbean Sea off Colombia
Length	1,632	1,064–1,704 (1,371) 3	1,592	1,512	3,072
Width at pharynx	248	152–376 (265)	400	352	224
Width at VS 3	624	296–480 (419)	520	512	656
Width at PT 3	632	304–608 (460)	592	512	632
Forebody L 3	688	264–496 (400)	400	392	928
Hindbody L	944	752–1,224 (971)	1,192	1,120	2,144
Oral sucker (OS) L	192	152–216 (169)	196	208	288
OS W 3	204	188–216 (200)	236	232	168
Prepharynx L	0	0 (0)	0	0	24
Pharynx L	148	92–140 (116)	100	132	164
Pharynx W	112	92–136 (110)	128	160	160
Esophagus L	320	216–444 (343) [n = 10] 3	52	384	624
Intestinal bifurc. anterior to VS	88	0–28 (7)	60	0	52
Ceca W @ widest point	Left = 104; Right = 72	Left = 40–104 (65); Right = 40–96 (63)	Left = 48; Right = 44	Left = 188; Right = 188	Left = 60; Right = 84
Post-cecal region L	124	64–200 (121)	184	128	248
VS L	304	236–352 (290)	344	320	408

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TABLE 2. (Continued)

Parasite	Podocotyle pearsei Manter ,	Podocotyle pearsei Manter ,	Podocotyle sp. 1	Podocotyle sp. 2	Podocotyle sp. 3
	1934	1934
VS W	384	272–424 (358)	432	368	568
AT 3 L	90	88–120 (105)	140	120	212
AT W	240	160–280 (208)	276	168	364
PT L	94	116–180 (152)	140	120	344
PT W	216	156–264 (207)	272	192	312
AT to PT	0	0 (0) [n = 10]	0	0	16
Post-testicular region (PTR) L	376	208–432 (309)	264	400	896
PTR W at mid-point	408	248–488 (362)	432	392	480
Cirrus pouch (CP) L	256	226–304 (257) [n = 9]	492	308	348
CP W	96	70–104 (85) [n = 10]	62	104	160
Genital pore (GP) to lateral	72	48–92 (66) [n = 10]	96	60	120
margin
GP anterior to VS	208	44–132 (84) [n = 10]	120	0	156
GP anterior to intestinal bifurc.	80	32–84 (65) [n = 10]	40	20	52
Pre-ovarian region L	1,160	480–984 (759)	872	784	1,480
Ovary (OV) L	88	60–116 (82) [n = 10]	192	84	140
OV W	212	100–236 (161) [n = 10]	292	156	340
VS to OV	164	52–188 (102) [n = 10]	144	120	112
OV to AT	0	0 (0)	0	0	0
Vitelline follicle L	40–76 (61) [n = 5] 3	24–68 (41) [n = 55] 3	24–50 (37) [n = 5] 3	26–40 (32) [n = 5] 3	48–92 (75) [n = 5] 3
Vitelline follicle W	28–52 (37) [n = 5] 3	12–60 (24) [n = 55] 3	20–24 (22) [n = 5] 3	16–24 (20) [n = 5] 3	40–60 (48) [n = 5] 3
Vitelline fields to VS	0	0 (0) [n = 10]	Right band = 0; Left	0	0
band = 52
Vitelline reservoir L	90	50–110 (75)	130	130	68