A revision of Brady’s 1869 study of the Ostracoda of Hong Kong

This paper is a revision of Brady’s 1869 study of the Ostracoda of Hong Kong in ‘Les Fonds de la Mer’. In this he described the following nine new species: Cyrherella cingulata, Bairdia elegans, Bythocythere orientalis, Loxoconcha sinensis, L. hastata, Cytheridea impressa, Cythere cymba, C. euplectella and C. salebrosa. A detailed reappraisal of Brady’s original material which is deposited in the Hancock Museum, Newcastle-upon-Tyne, UK, and the Centre d’Etudes et de Recherches Scientifiques, Biarritz, France has revealed that the specimens of L. hastata are apparently lost. Holotypes and lectotypes have been designated by the authors for the other eight species. Those species which were subsequently recorded by Brady (1880) in the Challenger Report, such as C. cingulata, B. orientalis, L. sinensis and C. euplectella are demonstrated not to be conspecific with their original types first described in 1869. The following 10 species, Bythoceratina virgatella Hu, 1983 and B. cassidoidea Zhao, 1985; Cyprideis yehi Hu & Yeh, 1978, Sinocytheridea sinensis Hou. 1978, S. latiovata Hou & Chen, 1982, 5. lotjga Hou & Chen, 1982 and Eucytheridea sinobesani Hu, 1984: Cythereis subconvexa Kajiyama, 1913 and Aurila miii Ishizaki, 1968: Cythereis assimilis Kajiyama. 1913 are placed by the authors in the synonymies of Brady’s B. orientalis, C. impressa, C. cymba and C. salebrosa respectively.


INTRODUCTION
G. S. Brady. the first worker to study the marine ostracods of China. in 1869 reported on an ostracod fauna consisting of 16 species from Hong Kong in 'Les Fonds de la Mer'. He described and illustrated the following nine new species: Bairdia elegans. Cythere c!m bu, C. euplectellu, C. salebrosu, Cytheridea irnpressa. Loxocoticha hastata. L. sinensis, Bythocvthere orientalis and Cytherella cirigulata, and listed the following eight species: Bairdia subdeltoidea (Munster. 1830). Cvthere cerebralis Brady, 1868. C. cribriformis Brady. 1866, C. crispata Brady. 1868, C. darwitiii Brady, 1868, C. hodgii Brady, 1865, Pontocypris davisoni Brady, 1868and Xestoleberis aurantia (Baird, 1838. However. the description of some of his new species and the illustration provided in this paper are inadequate by modern standards and have been responsible for both taxonomic and ecological confusion by some subsequent authors. Two principal types of confusion have occurred. Firstly, some species names have been used by subsequent authors for species clearly not conspecific with Brady's type material. Brady himself provides an example. The species described by Brady in 1880 from the Challenger Expedition such as Bythocytk ere orietitalis. Cythere euplectella. Loxocorichu sinensis and Cytherella cingulata are certainly not the same as those species first described by Brady in 1869 from Hong Kong. Secondly. there have been several synonymous species erected by later workers, such as Cythereis assimilis Kajiyama, 1913. Cythereis subcotivexa Kajiyama, 1913and Aurila miii Ishizaki. 1968, Cyprideis yehi Hu & Yeh, 1978, Sinocytheridea sirierisis Hou, 1978, S . latiovafa Hou & Chen, 1982, S . longa Hou & Chen, 1982 and Eucytheridea siriobesani al slides to new separate slides: C. cingulata (no. 1.08.32), B. orientalis (no. 1.35.35), B. elegans (no. 1.14.35), C. euplectella (no. 1.15.15), C . impressa (no. 1.23.44) and L. sinensis (no. 1.46.46). Additionally, there are another three of Brady's original slides (nos. 1.08.06, 1.11.10, 1.12.05) on which the identification is Cythere cerebralis, C. cribriformis and C. darwinii respectively. Their locality, however, is doubtful as each slide was also labelled with two place names, "Hong Kong and Java" or "Hong Kong and Java Sea". It is impossible, therefore, to be certain which specimens are really from Hong Kong. For this reason, the authors have not made use of this latter material in this paper.
A few specimens of five of the species are deposited in the Centre d'  (Brady).            Diagnosis. Medium. surface covered by faint reticulation with a marginal rib which extends from the mid-dorsal margin along the anterior, ventral and posterior margins. becoming vertical posteriorly. a horizontal dorsal rib, which is about half the length of the carapace and which unites posterodorsally with the vertical posterior marginal rib. and a very weak, short. narrow. horizontal rib which extends just below the muscle-scar depression. Remarks. As the specimen illustrated by Brady (1869) is a right valve, it is reasonable to designate the right of Brady's two original valves as the lectotype and the left one as the paralectotype. Of the specimens reported by Brady (1880) from Hong Kong. Indonesia and Australia. only those (pl. 43. figs. la-d) are conspecific with his 1869 type material. The others (pl. 43, figs. le-g. 2a-d) are obviously different species due to their different ornamentation. The specimens described under the name of C. citzgirlatu by Gou et al. (1983). possessing a continuous marginal rib, are virtually the same as Brady's 1880 specimens (pl. 43, figs. le-g) which are clearly not C. cingulatu. Kingma (1948) illustrated one specimen from Indonesia which is probably not C. cingulcrtu since it has a long prominent horizontal rib below the muscle-scar depression. 2.05.31 to the present slide. and it has to be considered as the holotype of this species. Dimensions (in mm).
Length Height Holotype (HMNT 1.35.35) RV 0.71 0.36 Diagnosis. This species is characterised by its strong posteroventral spine. from its base two long and prominent ventral ribs extend anteriorly and two short and weak ribs posteriorly. Median sulcus distinct; anterior lobe relatively swollen and covered by weak reticulation; posterodorsal rib prominent. extending from above the anterior lobe to just in front of the caudal process. Remarks. The specimens reported by Brady (1880)  Diagnosis. Oblong to ovate in lateral view with subparallel dorsal and ventral margins. Surface coarsely reticulate with two relatively prominent ribs ventrally: the outer one parallel to the ventral margin and the inner one slightly concave posteriorly. The posterodorsal area is markedly swollen and on it the muri become thickened and more elevated. and in dorsal view the posterior margin is broadly obtuse. The male is more elongate and slimmer than the female with a diagnostic small patch of fine punctae just above the posterodorsal swelling.
Remarks. Both the names Loxoconchu sinensis and L. hastutu are written on Brady's original slide no. 2.05.32. but only specimens of the former species were found. No specimens of L . hustutu were found anywhere in Brady's Collection and they are, therefore, presumed lost. L . sirierisis and L . hustata are not easily confused on the basis of their original illustrations. The latter is much higher and the posteroventral margin is markedly convex. We have checked the specimens in the Challenger collection in both the British Museum and the Hancock Museum. under the name of L . sirierzsis, recorded by Brady (1880) from Hong Kong and Japan. and found none of them to be conspecific with the type as they all lack the diagnostic posterodorsal swelling. It is evident. therefore, that those specimens were subsequently misidentified by Brady himself. This misidentification has influenced subsequent authors, notably Kingma (1948). Gou et ul. (1983). (1985) and Zhao et al. (1985) in their erroneous intepretation of this species. All of these authors have used the name L. sinensis for species which are not conspecific with Brady's original material from Hong Kong. Distribution. Only Hong Kong. Recent.
Family Hemicytheridae Puri, 1953 Genus Mutilus Neviani, 1928 Muti1ii.s salehrosa (Brady)  0.41 Diagnosis. Carapace inflated medianly; coarsely and irregularly reticulate suface characterised by sub-alar ventrolateral rib and radial ribs. Remarks. Brady's 1869 illustration was drawn based on the LV which is thought to be lost. compared with which thc present specimen is ii little lower and more elongate which represents the major diffcrcncc bc-Explanation of Plate 2 Figs. 1-5. Loxocoticha sirierisis Brady.      x 110).
(all x 70). tween LV and RV. From the material of Okubo (1980) and Yajima (1982) which agree well with the present type, we believe that Kajiyarna's C. assirnilis is conspecific with the present species. Bearing weaker and more regular reticulation, the material of Hou et al. (1982) is quite different from M . salebrosa and probably belongs to M . ishizaki Okubo, 1980. Distribution. Hong Kong, Recent;Japan, late Pleistocene to Recent. 18691880191319681976197719801985Genus Aurila Pokorny, 1955 Aurila cymba (Brady) 1869 (PI. 2, figs. 9-12) Cythere cymba Brady: 157,pl. 16,Brady: 80.81,pl. 20,pl. 1,figs. 74,75. Aurila miii Ishizaki: 22,pl. 1,fig. 9;pl. 4 Diagnosis. Surface ornamented with concentric and rounded pits which become reticulations peripherally, long and prominent ventral marginal rib, anterior marginal rib which joins the eye-tubercle and extends to the mid-anterior part of the dorsal margin, short and curved posterodorsal rib, and radial ribs of which the anteroventral and post-median ones are most pronounced. Remarks. On the basis of detailed comparisons, we are convinced that the material of C. cymba subsequently described by Brady  Surface covered by concentric reticulation, consisting of 'T'-shaped muri and deep fossae whose openings are slit-like in lateral view. Holamphidont hinge with stepped anterior tooth and bulb-like posterior tooth. Avestibulate; frontal scar single and rounded.
Remarks. This species is very readily identified by its diagnositic reticulation of 'T'-shaped muri. C. euplectella illustrated by Brady (1880) and Puri & Hulings (1976) has reticulation which lacks these characteristic muri and is evidently not conspecific with Brady's 1869 type material. We tentatively refer this species to Lankacythere Bhatia & Kumar, 1979 based mainly on its hinge and its deep and concentric fossae, despite the fact that the posterodorsal rib, one of the diagnostic feature of this genus, is not developed. Distribution. Recent, beside Hong Kong, it has been widely encountered in bottom sediments of the South and East China Seas Zhao et al.. 1985) and of the Malacca Straits (Whatley & Zhao, in press Brady (1869). The species clearly differs from the Recent North West European species, X . aurarifia which has a well rounded posterior margin and an anteroventral process of the LV which strongly overlaps the RV. Distribution. Japan, late Pleistocene to Recent; Kurile Islands of the USSR; China, Recent.