Quadriacanthus ossaensis Bahanak, Nack & Pariselle, 2016

Bahanak, Dieu ne dort, Nack, Jacques, Pariselle, Antoine & Bilong Bilong, Charles F., 2016, Description of three new species of Quadriacanthus (Monogenea: Ancyrocephalidae) gill parasites of Clarias submarginatus (Siluriformes: Clariidae) from Lake Ossa (Littoral region, Cameroon), Zoologia (e 20160044) 33 (4), pp. 1-8 : 3-4

Quadriacanthus ossaensis Bahanak, Nack & Pariselle , sp. nov.

Fig. 4

urn:lsid:zoobank.org:act:81837D50-AFB3-4C9A-AE61-073D2B42DE1A

Description (based on 33 specimens, all mounted in GAP): adults measure: 368 ± 86.8 (188.9-597.7) long, 65. 5 ± 16. 1 (33.7- 98.9) wide at level of ovary). Pharynx circular is 21 (18-24) wide. Winding tubular penis, widened at basal extremity, regularly tapering to the distal one Pe = 28.2 ± 3.1 (23.9-32.4). Accessory piece, tubular, slightly arched and ending with two expansions: one fork shaped, the other one chevron shaped, Ap = 26.5 ± 2.9 (22-30.1). Tubular vagina, Vg = 24.9 ± 5 (20.9-30.6). Hooklets pair I = 13.5 ± 0.9 (11.7-15.4), II = 13.3 ± 0.8 (12-15.6), III = 14.3 ± 0.6 (12.1-15.7), IV = 24.8 ± 0.5 (23.8-25.7), V = 12.9 ± 0.7 (11.7- 14.3), VI = 13.2 ± 0.8 (11.9-15), VII = 12.7 ± 0.8 (11-14.2). Dorsal bar composed of a developed trapezoidal centre, Ct = 17.4 ± 2.7 (14.5-21.9), w = 9.7 ± 0.8 (8.2-10.7) wide, with one posteriorly directed rectangular process, h = 8.6 ± 1.4 (7.1-9.9), and two lateral expansions, x = 20.4 ± 1.2 (18.9-22). Dorsal anchor without shaft, but with curved blade and short point, a = 28.3 ± 1.2 (26.9-30.8), ba = 9.1 ± 0.6 (8.1-9.8), e = 6.2 ± 1.2 (5.2-8.6), triangular dorsal cuneus (or patch) slightly curved, i = 5.2 ± 0.5 (4.8-5.8), j = 15.7 ± 0.6 (15-16.8). Ventral bar V-shaped, made up of two branches medially articulated, x = 32.6 ± 1.3 (30.4-36.2), w = 4.3 ± 0.5 (3.3-5.3), ventral anchor quite similar to dorsal one, a = 19.9 ± 1 (18.6-21.4), ba = 4.8 ± 0.3 (4.1-7.7), e = 9.8 ± 1.2 (7.7-12.1), triangular ventral cuneus, i = 2.4 ± 0.4 (1.6-3.3), j = 4.1 ± 0.7 (3.5-5.8).

Type host. Clarias submarginatus Peter, 1882 .

Site. Gills.

Type locality. Lake Ossa , Cameroon (3°45’- 3°51’N, 9°58’- 10°03’E).

Type specimens. Holotype deposited at the Royal Museum for Central Africa (Tervuren): #37933 . Paratype deposited at the Royal Museum for Central Africa (Tervuren): #37934 .

Materials studied. 43 host individuals and 33 monogeneans.

Parasitic indices. Prevalence = 81.8%, mean abundance = 4.4 ± 5.8.

Etymology. The specific name, ossaensis , refers to the type locality of this species.

Remarks. The morphologies of the penis and of the accessory piece of Q. ossaensis sp. nov. are similar to Quadriacanthus ayameensis N’Douba, Lambert & Euzet, 1999 , a gill parasite of Heterobranchus longifilis (Valenciennes, 1840) and Heterobranchus isopterus Bleeker, 1863 in the rivers Bia, Agnéby and in Lake Ayamé ( Ivory Coast). Quadriacanthus ossaensis can be distinguished from Q. ayameensis species by having one tip of the distal end of the accessory piece shaped as a fork, by the size of the dorsal cuneus (patch) (i = 2.5-7 vs 7-10, j = 13.8-18 vs 8-11), the trapezoid shape of the central sclerite of the dorsal bar, and the shape (thin and twisted) of the branches of the ventral bars.

Figures

Figure 4. Sclerotized parts ofQuadriacanthus ossaensis sp. nov.: (Cc) copulatory complex, (Da) dorsal anchor, (Db) dorsal bar, (Dcn) dorsal cuneus, (H) hooklets, (Va) ventral anchor, (Vb) ventral bar, (Vcn) ventral cuneus, (Vg) vagina. Scale bar: 20 µm.