罗源湾水螅水母纲一新属二新种

A NEW GENUS AND NEW SPECIES OF HYDROPOLYPAE- HYDROMEDUSAE FROM THE LUOYUAN BAY, FUJIAN PROVINCE, CHINA

本文标本系于福建省罗源湾水域采集的。发现在水螅水母纲的裸鞘花水母亚纲、丝螅水母目的唇腕水母科中一新属——拟唇腕水母属Pseudorathkea gen. nov.,一新种大胃拟唇腕水母Pseudorathkea macrogastrica nov. sp.;在水螅水母纲的被鞘软水母亚纲、锥螅水母目、真唇水母科的真唇水母属中一新种,多丝真唇水母Eucheilota multicirtis nov. sp.

In an investigation on the plankton collected from Luoyuan Bay during November 1986-October 1987, a new genus and two new species of Hydromedusae are found. Of which, one new genus and one new species belong to the family Rathkeidae of Athecatae-Anthomedusae and the another to the family Eucheilotidae of Thecatae-Leptomedusae. All type specimens are deposited in the Department of Oceanography, Xiamen University, China.Pseudorathkea, gen. nov.Rathkeidae with eight radial canals and eight marginal clusters of tentacles; perredial bulbs larger than the interradial; with four lips elongated to from bifurcate oral arms with one pair of terminal nematocyst knobs.The family Rathkeidae is known only by three genera: Rathkea Brandt, 1838, Octorathkea Uchida, 1927 and Allorathkea Schmidt, 1972. Owing to the fact that genus Oclorathkea is without oral arms, it had been placed in the family Platystomidae by Zhang (1982), later Bouillon (1985) revised it to family Austratomedusidae Russell, 1971 inasmach as the morphological character of these two families are the same. Therefore, the family Rathkeidae up to the present has two genera. The new genus closely resembles Allarathkea, but differs from the latter in four lips elongated to form bifurcate oral arms with one pair terminal nematocyst knobs.Type species: Pseudorathkea macrogastrica, sp. nov.Pseudorathkea macrogastrica, gen. et sp. nor. (fig. 1)Umbrella 0.62-1.0 mm high, 0.68-0.88 mm wide, nearly bellshaped, with thick gelatinous substance in bell apex, with eight radial canals ?nd one circular canal; stomach nearly spherical, very large and lies on a short peduncle, occupying about 2/3 as long as the height of the bell cavity; gonads surrounding the wall of the stomach; mouth with four lips elongated to form bifurcate oral arms with one pair of terminal nematocyst knobs; with five marginal tentacles in each perradial, three in each interradial group, perradial bulbs larger than the interradial, all with dark brown color.Holotype, No. AOB-HL048, Feb. 18, 1987. Paratypes, No. AOB-HLO49-51, Feb. 18, 1987. 4 specimens collected from Luoyuan Bay, Fujian Province (26°22'N, 119°44'E).Eucheilota multicirris, sp. nor. (fig. 2)Umbrella 0.7-1.0 mm high, 1.5-2.0mm wide, nearly hemispherical, with thick jelly; manubrium short, about 1/4 as long as the bell cavity; mouth quadrate, with four slightly crenulated lips; with four radial canals and one circular canal; perradial tentacles 4, each with 6-7 pairs of lateral cirri, between successive tentacles usually three marginal warts, the middle one the largest, without lateral cirri; marginal vesicles 8, each with 2-3 concretions; gonads ellipse-shaped, on the radial canal near the circular canal: perradial marginal bulbs with black pigment.This new speeies with larg perradial tentacles and without medusa-buds on-gonads, which differs from E. paradoxia Mayer, 1900 with medusa-buds; E. maculata Hartlaub, 1894, E. flevensis van Kampen, 1922, E. faresti Goy, 1979, E. ventricularis McCrady, 1857 and E. comata (Bigelow, 1909) with 16 or a number of marginal tentacles; E. bakeri (Torrey, 1909) and E. diademata Kramp, 1959 with only 2 perradial tentacles; but resembles E. duodecimalis A. Agassiz, 1862, E. maasi Neppi et Stiasny, 1911, E. menoni Kramp, 1959, E. tropica Kramp, 1959, E. intermedia Kubota, 1984 and E. macrogona Zhang et Lin, 1984, which differs from all the latter species in having each perradial tentacle with 6-7 pairs of lateral cirre, marginal warts without lateral cirri; each marginal vesicle with 2-3 concretions.Holotype, No. AOB-HLO52, Aug. 23, 1987. Paratype, No. AOB-HL053; July 17, 1987. 2 specimens collected from Luoyuan Bay, Fujian Province (26°22'N, 119°44'E).