Parancylodiscoides signiferi, Cruces & Chero & Sáez & Luque, 2017

Cruces, Celso L., Chero, Jhon D., Sáez, Gloria & Luque, José L., 2017, Dactylogyrids (Monogenea) parasitic on marine fish from Peru including the description of a new species of Haliotrema Johnston & Tiegs, 1922 and two new species of Parancylodiscoides Caballero & C. & Bravo-Hollis, 1961, Zootaxa 4311 (1), pp. 111-121 : 117-119

Parancylodiscoides signiferi n. sp.

( Figs. 17–24 )

Type-host: Hemanthias signifer (Garman) (Serranidae) , damsel bass.

Site of infection: Gill filaments.

Type locality: Puerto PiZarro , Tumbes, Peru (45°54'S, 81°05'W), South AmeriCa.

Prevalence: 4 of 16 hosts infeCted (25%) with a total of 43 worms.

Mean intensity of infection: 11 monogeneans per infeCted host (range 9–14).

Specimens deposited: Holotype, MUSM 3508; 31 paratypes, MUSM 3509–3539; 2 paratypes, CHIOC 38851a b.

Etymology: The speCifiC epithet refers to the speCifiC name of the type host.

Description: Based on 10 speCimens mounted in Gray and Wess medium and 22 fiXed in 4% hot formalin and stained with Gomori’s triChrome. Body fusiform ( Fig. 17 ), 594–898 (742; n = 32) mm long; greatest width 102– 136 (122; n = 32) usually at midbody length. Tegument smooth. CephaliC region broad; CephaliC lobes poorly developed; 3 bilateral pairs of ConspiCuous head organs; bilateral pair of CephaliC glands lateral to pharynX. Eyespots absent; aCCessory ChromatiC granules few, sCattered in CephaliC area. PharynX subspheriCal, with maXimum width 34–46 (40; n = 22); esophagus short; intestinal bifurCation postpharyngeal; intestinal CeCa unite posteriorly to gonads, laCking divertiCula. PedunCle broad, short to elongate. Haptor subquadrate, differentiated from body proper, 64–77 (71; n = 25) long; 81–107 (93; n = 8) wide; bilateral Claviform reservoirs on haptor not observed. Ventral and dorsal anChors similar in siZe and shape; eaCh with well-developed elongate superfiCial root, rounded deep root, slightly Curved shaft, short Curved point with furrow on eXternal surfaCe ( Figs. 18–19 ). Ventral anChor 60–66 (63; n = 15) long, base 18–21 (19; n = 15) wide. Dorsal anChor 60–65 (63; n = 15) long, base 18–22 (20; n = 15) wide. AnChors with fine ConspiCuous alae ( Figs. 18–19 ). Ventral bar 40–51 (46; n = 17), elongate, posterior margin with two protuberanCes and lateral ends enlarged, rounded ends ( Fig. 20 ). Dorsal bar 56–78 (69; n = 12) long, flattened, bifurCate ends, anterior arm of bifurCation longer than posterior arm ( Fig. 21 ). Fourteen similar hooks, 14–15 (14; n = 11) long, eaCh with depressed thumb, uniform shank and deliCate point ( Fig. 22 ); filamentous hook (FH) loop about shank length. Male Copulatory organ (MCO) 139–162 (150; n = 28) long, tubular with a loop at distal end; slightly eXpanded base having a short and broad arm direCted posteriorly ( Fig. 23 ); aCCessory pieCe absent. Testis large, interCeCal, ovate, not lobulated, lying near body midlength, 104–160 (141; n = 17) long, 96–156 (126; n = 17) wide; proXimal vas deferens apparently looping left intestinal CeCum, dilating to form large fusiform seminal vesiCle slightly in left side of trunk, posterior to MCO; single prostatiC reservoir lying deXtrolateral to MCO, pyriform to fusiform; prostatiC glands ConspiCuous, interCeCal, surrounding the MCO. Ovary 40–62 (53; n = 10) long, 38–67 (57; n = 6) wide, pyriform, lying to right of anterior end of testis. Vaginal aperture deXtrolateral at level of base of MCO; vaginal vestibule elongates, lightly sClerotised, lying obliquely on right side of body anterior to ovary; vaginal duCt narrow, running posteriorly to join subspheriCal seminal reCeptaCle. OviduCt, ootype and uterus not observed. Vitelline folliCles dense throughout trunk, absent in regions of reproduCtive organs. Egg oval ( Fig. 24 ), 75–78 (77; n = 2) long, 54–55 (55; n = 2) wide, with single short filament at aboperCular pole, 5–7 (6; n = 2) long.

Remarks: Parancylodiscoides signiferi n. sp. Could be distinguished from all Congeners by the morphology of the MCO, whiCh is tubular with a loop at distal end and a slightly eXpanded base having a short and broad arm. Parancylodiscoides signiferi n. sp. also differs from P. chaetodipteri , P. longiphallus and P. platacis , beCause these speCies have deXtroventral vaginal apertures (deXtrolateral in the new speCies) and a lobulated testis (not lobulated in the new speCies).

Parancylodiscoides signiferi n. sp. most resembles P. macrobaculum and P. peruensis n. sp. by having the base of the male Copulatory organ with an arm direCted posteriorly, a deXtrolateral vaginal aperture and a not lobulated testis. In addition to the aforementioned distinguishing CharaCters, P. signiferi n. sp. is easily distinguished from P. macrobaculum by having a dorsal bar with anterior arm of bifurCation longer than posterior arm (anterior arm of similar siZe as the posterior in P. macrobaculum ). Finally, the new speCies having anChor points with furrow on eXternal surfaCe (absent in P. peruensis n. sp.).

Figures

FIGURES 17 – 24. Parancylodiscoides signiferi n. sp. 17. Whole Worm (Ventral). 18. Ventral anchor. 19. Dorsal anchor. 20. Ventral bar. 21. Dorsal bar. 22. Hook. 23. Male copulatory organ. 24. Egg.