Ju-Shey Ho

Why do symbiotic copepods matter

Currently, less than 10% of the members of the World Association of Copepodologists are working actively on symbiotic copepods. This surprisingly small guild of workers is thought to result from a general lack of understanding of the importance of symbiotic copepods. Symbiotic copepods as a whole comprise more than one-third (4224/11956 or 35.33%) of known copepods. They are found not only in the five major orders of Copepoda (Calanoida, Harpacticoida, Cyclopoida, Poecilostomatoida and Siphonostomatoida), but also in association with all major phyla of marine animals, ranging from sponges up to mammals (cetaceans). Discussion on these subjects is augmented with information on the impact of symbiotic copepods on aquaculture, and their exhibition of unusual biological phenomena. It is concluded that copepodologists today need to pay more attention to the symbiotic copepods, if copepodology is to become a major subject of modern biological sciences.

Species of Caligus Müller, 1785 (Copepoda: Caligidae) parasitic on marine fishes of Taiwan.

Six species of copepods of the genus Caligus (Caligidae, Siphonostomatoida) parasitic on marine fishes of Taiwan are reported. They are: C. absens n. sp. from Priacanthus blochii and P. macracanthus; C. epinepheli Yamaguti, 1936 from Scolopsis vosmeri; C. kanagurta Pillai, 1961 from Decapterus kurroides; C. laticaudus Shiino, 1960 from Lutjanus vitta and Parapristiopoma trilineatum; C. nengai Rangnekar, Rangnekar & Murti, 1953 from Triacanthus biaculeatus; and C. rotundigenitalis Yü, 1933 from Drepane punctata, Liza macrolepis and Terapon jarbua. C. distortus Pillai & Natarajan, 1977 is relegated to a synonym of C. nengai and C. multispinosus Shen, 1957 reported by Lin et al. (1994) from the cultured sea bream Acanthopagrus schlegeli is a misidentification for C. rotundigenitalis Yü, 1933.

Ostrincola koe (Copepoda, Myicolidae) and mass mortality of cultured hard clam (Meretrix meretrix) in China.

We discuss the primary cause of mass mortalities of cultured hard clam (Meretrix meretrix) which occurred in 1988 and 1989 in southern Jiansu, China. Based on a re-examination of the old samples and analysis of information from Japan and Korea, it is concluded that the population explosion of the parasitic copepod, Ostrincola koe Tanaka, in the clam mantle cavity, combined with an acute vibriosis in the intestine, were responsible for the mass mortality. Other incidences of hard clam mass mortalities in China, Korea and Taiwan in the 1970s and 1980s are also discussed.

Copepod phylogeny : a reconsideration of Huys & Boxshall's 'parsimony versus homology'

A hypothesis of copepod phylogeny proposed by Huys & Boxshall (1991) was reanalyzed with the PAUP computer program by using TOPOLOGY and DELTRAN options to remove many character reversals. The remaining reversal characters were removed employing the Camin-Sokal Optimization Procedure. The resulting tree is two steps longer than the best fit tree (Tree C) obtained strictly by using parsimony criterion and optimizd with the same procedure. Further analysis revealed that the differences in these two cladograms are essentially due to the differential treatment of nine characters and varied assumptions of ‘missing state’ in another six characters as being apomorphies or plesiomorphies. Huys & Boxshalls hypotheses of character polarity in the copepods are shown not to be in conflict with the principle of parsimony. According to the principle of parsimony, their Tree C is the best supported phylogenetic hypothesis for Copepoda.

Phylogenetic Analysis of Copepod Orders

Ten orders of the subclass Copepoda were cladistically analyzed using 21 morphological characters. Platycopioida is the sister taxon of the Calanoida and this gymnoplean clade is the sister group of the podoplean clade, which consists of eight orders. Misophrioida is, in turn, the sister taxon of the clade that contains the rest of the podoplean orders. Interestingly, the four orders (Poecilostomatoida, Siphonostomatoida, Monstrilloida, and Cyclopoida) containing species symbiotic with aquatic animals are monophyletic. Harpacticoida, Mormonilloida, and Gelyelloida are monophyletic in a fully resolved cladogram. Comparisons were made between this newly reconstructed scheme of copepod phylogeny and the previously proposed schemes. A cladistic analysis of the copepod orders was first conducted by Geoffrey A. Boxshall and presented in 1984 at the Second International Conference on Copepoda held in Ottawa, Canada. This original scheme of copepod phylogeny was reconstructed with 12 morphological characters. Later, Boxshall added 7 more characters to his analysis and the scheme constructed anew was

A NEW SPECIES OF COPEPODA (THAUMATOPSYLLIDAE) SYMBIOTIC WITH A BRITTLE STAR FROM CALIFORNIA, U.S.A., AND DESIGNATION OF A NEW ORDER THAUMATOPSYLLOIDA

Abstract A new species of thaumatopsyllid copepod, Caribeopsyllus amphiodiae, is described based on adult specimens reared from nauplii inhabiting the stomach of a burrowing, amphiurid brittle star, Amphiodia urtica (Lütken), collected in California, U.S.A. It is the first member of the family to be reported from the eastern Pacific Ocean. Caribeopsyllus chawayi, its only known congener, inhabits the Caribbean Sea. All other thaumatopsyllid species occur in the eastern hemisphere. Caribeopsyllus amphiodiae is only the second thaumatopsyllid of which both sexes and sexual dimorphism have been described and for which a host species has been identified. Caribeopsyllus differs from confamilial genera by the presence of a 1-segmented leg 4 exopod. The new species is distinguished from C. chawayi by its general habitus, and by the absence of spiniform processes at the base of each exopodal spine of leg 1 and the first three exopodal spines of leg 2. Analysis of the phylogenetic relationships of Thaumatopsyllidae shows that it is not a member of any of the other previously established orders of Copepoda. Accordingly, a new order, Thaumatopsylloida, is proposed to accommodate the five species of thaumatopsyllids thus far reported and is shown to be a member of a Thaumatopsylloida-Monstrilloida-Siphonostomatoida clade.

Developmental stages of Caligus epidemicus Hewitt, a copepod parasite of tilapia cultured in brackish water

The larval development of Caligus epidemicus comprises ten stages: two nauplii, one copepodid, six chalimus, and one preadult (young adult) stages. The morphology of each of these ten instars is described based on material reared from eggs in the laboratory. Addition of fifth and sixth chalimus stages in the ontogeny of C. epidemicus is discussed in the light of the developmental changes in the leg armature. Some peculiarities about the structure of the frontal filament in various chalimus stages are also discussed.

Harpacticoid copepods (Thalestridae) infesting the cultivated Wakame (brown alga, Undaria pinnatifida) in Korea

Two species of thalestrid harpacticoid: Amenophia orientalis n. sp. and Parathalestris infestus n. sp., are described based on specimens collected from Soando Island in Korea. These copepods infest the cultivated brown alga, Wakame, Undaria pinnatifida (Harvey), producing galls with pinholes (0·5–1·1.5 mm in diameter) on the fronds, midribs, and sporophylls. A. orientalis outnumbered P. infestus in all of the observed incidences; however, the fecundity of the latter species is twice that of the former.

New Family of Poecilostomatoid Copepods (Spiophanicolidae) Parasitic on Polychaetes From Southern California, With a Phylogenetic Analysis of Nereicoliform Families

ABSTRACT A new genus and species, Spiophanicola spinulosus, is described as a representative of a new family of poccilostomatoid copepods parasitic on three species of polychaetcs: Spio-phanesberkeleyorum Pettibone, S. missionensis Hartman, and S. kroyeri Grube collected off Huntington Beach and Santa Monica in southern California. Phylogenetic analysis of the nereicoliform families has revealed that there arc three major lines of evolution, namely, the clausidiid-synaptiphilid line, the clausiid-nereicolid line, and the catiniid-complex. The Spiophanicolidae is closest to the Serpulidicolidae on the clausiid-nereicolid line. which contains the bulk of the nereicoliform families. Another new family, the Entobiidae. is established to accommodate Entobius Dogiel, 1908, a genus that lives in the intestine of polychaetes.

Two species of Ergasilidae (Copepoda: Poecilostomatoida) parasitic on the gills of Mugil cephalus Linnaeus (Pisces: Teleostei), with proposition of a new genus Dermoergasilus

A new genus of Ergasilidae (Dermoergasilus) is proposed to accommodate Ergasilus amplectens Dogiel et Akhmerov, 1952; E. coleus Cressey, 1970; and E. semicoleus Cressey, 1970. Dermoergasilus amplectens (Dogiel et Akhmerov, 1952) and Nipergasilus bora (Yamaguti, 1939) are redescribed based on the specimens recovered from the gills of Mugil cephalus L. collected in Kojima Bay, Okayama Prefecture, Japan.