Parancylodiscoides peruensis, 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 : 115-117

Parancylodiscoides peruensis n. sp.

( Figs. 9–16 )

Type-host: Hemanthias peruanus (SteindaChner) (Serranidae) , splittail bass.

Site of infection: Gill filaments.

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

Prevalence: 3 of 12 hosts infeCted (25%) with a total of 51 worms.

Mean intensity of infection: 17 monogeneans per infeCted host (range 11–23).

Specimens deposited: Holotype, MUSM 3480; 27 paratypes, MUSM 3481–3507; 3 paratypes, CHIOC 38852a, b, C.

Etymology: The speCifiC epithet refers to the Country where the speCies was found.

Description: Based on 10 speCimens mounted in Gray and Wess medium and 21 fiXed in 4% hot formalin and stained with Gomori’s triChrome. Body fusiform ( Fig. 9 ), 597–949 (732; n = 31) mm long; greatest width 124–173 (144; n = 31) usually posterior to testis. 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 spheriCal, with maXimum width 31–53 (38; n = 20); esophagus short; intestinal bifurCation postpharyngeal; intestinal CeCa unite posteriorly to gonads, laCking divertiCula. PedunCle broad, short to elongate. Haptor subquadrate, differentiated from body proper, 57–73 (67; n = 10) long; 91–134 (111; n = 10) wide; bilateral Claviform reservoirs on haptor not observed. AnChors with fine ConspiCuous alae ( Figs. 10–11 ). Ventral anChor 57–67 (65; n = 15) long, with well-developed elongate superfiCial root, developed deep root, slightly Curved shaft, short Curved point ( Fig. 10 ); base 19–21 (20; n = 15) wide. Dorsal anChor 64–69 (67; n = 15) long, with well-developed elongate superfiCial root, rounded deep root, slightly Curved shaft, short Curved point ( Fig. 11 ); base 19–23 (21; n = 15) wide. Ventral bar 39–69 (48; n = 17) long, elongate, lateral ends enlarged, rounded and bilobed ends ( Fig. 12 ). Dorsal bar 61–98 (75; n = 12) long, flattened, with bifurCate ends, anterior arm of bifurCation longer than posterior arm ( Fig. 13 ). Fourteen similar hooks, 13–15 (14; n = 11) long, eaCh with depressed thumb, uniform shank and deliCate point ( Fig. 14 ); filamentous hook (FH) loop about shank length. Male Copulatory organ (MCO) 70–91 (83; n = 28) long, taperedshaped with Curved distal tip, bell-shaped base having two lateral knobs, short and broad arm direCted posteriorly ( Fig. 15 ); aCCessory pieCe absent. Testis large, interCeCal, ovate, not lobulated, 116–190 (144; n = 17) long, 54–78 (63; n = 17) wide; proXimal vas deferens 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 55–109 (82; n = 10) long, 34–47 (41; n = 10) wide, pyriform, lying to right of anterior end of testis. Vaginal aperture deXtrolateral at level of seminal vesiCle; 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. 16 ), 102–109 (106; n = 2) long, 74–87 (81; n = 2) wide, with single short filament at aboperCular pole, 23–27 (25; n = 2) long.

Remarks: Parancylodiscoides Caballero & C. & Bravo-Hollis, 1961 aCCommodates daCtylogyrids possessing a dorsal bar with bifurCated ends; hooks with protruding, blunt, and slightly depressed thumbs and undilated shanks; deXtroventral or deXtrolateral vaginal aperture leading to an elongate and oblique vaginal vestibule; ovary deXtral to the testis; and a Copulatory CompleX without aCCessory pieCe ( Kritsky & Bakenhaster 2016). Currently, Parancylodiscoides inCludes 4 speCies, namely P. longiphallus ( MaCCallum, 1915) ; P. chaetodipteri Caballero & Bravo-Hollis, 1961 ; P. platacis ( Young, 1968) and P. macrobaculum (Zhukov, 1983) . All of them desCribed from ephippid and serranid fish off PaCifiC and AtlantiC OCeans ( Kritsky 2012; Kritsky & Bakenhaster 2016).

Parancylodiscoides peruensis n. sp. Can be distinguished from all other speCies of Parancylodiscoides by having a tapered-shaped male Copulatory organ with Curved distal tip and a bell-shaped base having two lateral knobs and short arm.

Parancylodiscoides peruensis n. sp. most resembles P. macrobaculum by having the base of the male Copulatory organ with an arm direCted posteriorly, a deXtrolateral vaginal aperture and a not lobulated testis. However, the new speCies is easily distinguished from P. macrobaculum by the morphology of the arm assoCiated with the base of the MCO, whiCh is short and broad (long and narrow in P. macrobaculum ). In addition, P. peruensis n. sp. Can also be distinguished from P. macrobaculum by having a dorsal bar with anterior arm of bifurCation longer than posterior arm (anterior arm of similar siZe than the posterior in P. macrobaculum ).

Parancylodiscoides peruensis n. sp. differs from P. chaetodipteri , P. longiphallus and P. platacis by possessing a deXtrolateral vaginal aperture (deXtroventral in P. chaetodipteri , P. longiphallus and P. platacis ) and a not lobulated testis (lobulated in P. chaetodipteri , P. longiphallus and P. platacis ). Also, P. peruensis n. sp. differs from P. chaetodipteri , P. longiphallus and P. platacis by having a single short arm direCted posteriorly assoCiated with the base of the male Copulatory organ (two arms unequal in length in P. chaetodipteri , two elongate subequal arms in P. longiphallus and a single elongate arm direCted anteriorly in P. platacis ).

Figures

FIGURES 9 – 16. Parancylodiscoides peruensis n. sp. 9. Whole Worm (Ventral). 10. Ventral anchor. 11. Dorsal anchor. 12. Ventral bar. 13. Dorsal bar. 14. Hook. 15. Male copulatory organ. 16. Egg.