MONOGENEA OF MARINE FISHES FROM HAINAN ISLAND, CHINA, TWO SPECIES OF ATHERINICUS FROM THE GILLS OF ATHERINA BLEEKERI, WITH DESCRIPTION OF ONE NEW SPECIES

Atherinicus cornutus Bychowsky Nagibina, 1969 and Atherinicus hainanensis sp. nov. are described from the gills of Atherina bleekeri Gunther found in Lingao, Hainan Island,China.Atherinicus hainanensis sp. nov.(Figs.1-3)Host. Atherina bleekeri Gunther.Location. Gills.Locality. Lingao (19°54′ N, 109°30′E), Hainan Island.Date. 26 Mar. 2004.Type specimens. Holotype No.HNMF20040326-4-1 and paratype No. HNMF20040326-4-3, 5,6.Description. Body (0.330-0.600)mm ×(0.120-0.200)mm in size.Pharynx oval,(0.025-0.033)mm×(0.025-0.030)mm in size.Haptor well set of from the body, (0.043-0.075)mm×(0.070-0.100)mm in size, with 14 marginal hooklets. Marginal hooklets 0.020-0.025mm in length. Dorsal central anchors small, total length 0.028-0.030mm,basal portion 0.018-0.020mm, point 0.010-0.013mm, inner root 0.013-0.015mm, outer root about 0.003mm. Dorsal connective plate V-shaped, (0.003-0.005)mm×(0.025-0.040)mm in size. Ventral central anchors longer than the dorsal ones, total length 0.040-0.045mm, basal portion 0.028-0.035mm, point portion 0.015-0.020mm, inner root 0.015-0.020mm, outer root about 0.005mm.Ventral connective plate slightly straight, (0.004-0.008)mm×(0.038-0.053)mm in size.Copulatory apparatus 0.035-0.043mm in total length. Copulatory tube slightly straight, 0.038-0.043mm in length, width 0.003-0.004mm at the basal portion. Supporting apparatus S-shaped, about 0.028-0.038mm in length. Vagina marginal, funnel-like shaped, about 0.013mm×(0.010-0.013)mm in size. Egg has not been observed.Description based on 8 specimens. Type specimens are deposited in the Department of Biology. Hainan Normal University.Remarks. The new species is similar to A.subserratus Zhang et al., 2001 in the shape of central anchors, but differs in: 1) the dorsal connective plate of the new species is V-shaped, but that of the latter is concaving at the middle of the upper margin and with two hilly projections on the two sides; 2)the new species has a slightly straight copulatory tube, length 0.038-0.043 !mm, but that of the latter is curved by C-shaped at the basal portion, length 0.050-0.058mm; 3)the supporting apparatus of the new species is different from the latter; 4)the vagina of new species is funnel-like shaped, but that of the latter is arc-like with tooth-like projections in the interior wall. The species name refers to the typical location where the type specimens were collected.