Geoffrey A. Boxshall

Pathogens of wild and farmed fish: sea lice.

Part 1 Biology of sea lice: life cycle stages developmental factors anatomy behaviour epidemiology. Part 2 Control of sea lice: review fallowing chemotherapy vaccination biological control pathology.

Making waves: The repeated colonization of fresh water by copepod crustaceans

Twenty-two independent colonizations of fresh and inland continental waters are identified within six of the 10 currently recognized orders of copepods. This number is a minimum estimate and is expected to increase as knowledge of the phylogenetic relationships within copepod families improves. It does not include mere incursions into fresh water, defined as invasions without subsequent diversification (= speciation). The timing of colonization events is estimated, where possible, by inference from biogeographical data. This preliminary analysis supports, in general, a direct relationship between lineage diversity and time elapsed since colonization of fresh water. It is hypothesized that the invasion of South America by the Diaptominae, penetrating from the north, resulted in the displacement of the original calanoid inhabitants of that continent, the Boeckella group within the family Centropagidae, except at high altitude and higher latitudes. A similar, but more ancient, invasion by the Diaptominae is envisaged for Africa, with the original calanoid inhabitants, the Paradiaptominae, now being confined to marginal habitats, such as temporary waters. The analysis indicates a succession of at least four major waves of colonization of inland continental waters, although this may well be an artefact reflecting the indirect method of estimating colonization dates. Taxa currently making incursions into fresh waters may represent the next, or fifth, wave.

New Species in the Old World: Europe as a Frontier in Biodiversity Exploration, a Test Bed for 21st Century Taxonomy

The number of described species on the planet is about 1.9 million, with ca. 17,000 new species described annually, mostly from the tropics. However, taxonomy is usually described as a science in crisis, lacking manpower and funding, a politically acknowledged problem known as the Taxonomic Impediment. Using data from the Fauna Europaea database and the Zoological Record, we show that contrary to general belief, developed and heavily-studied parts of the world are important reservoirs of unknown species. In Europe, new species of multicellular terrestrial and freshwater animals are being discovered and named at an unprecedented rate: since the 1950s, more than 770 new species are on average described each year from Europe, which add to the 125,000 terrestrial and freshwater multicellular species already known in this region. There is no sign of having reached a plateau that would allow for the assessment of the magnitude of European biodiversity. More remarkably, over 60% of these new species are described by non-professional taxonomists. Amateurs are recognized as an essential part of the workforce in ecology and astronomy, but the magnitude of non-professional taxonomist contributions to alpha-taxonomy has not been fully realized until now. Our results stress the importance of developing a system that better supports and guides this formidable workforce, as we seek to overcome the Taxonomic Impediment and speed up the process of describing the planetary biodiversity before it is too late.

Comparative limb morphology in major crustacean groups: the coxa-basis joint in postmandibular limbs

Although it may have been plesiomorphic to a wider group of arthropods, one characteristic of the superclass Crustacea is the possession of a nauplius larva bearing three pairs of functional appendages, antennules, antennae and mandibles. The nauplius larva exhibits basically the same organization across the range of crustacean classes in which it is retained, and it is in the immediate postnaupliar phase, during the formation of the cephalon with its complement of five appendages, that the great diversity of crustacean form first becomes apparent. Cephalization has been a key engine driving crustacean evolution and diversification, and the specialization of the postmandibular limbs to form part of the cephalic feeding apparatus has been a major part of the process (Walossek, 1993). Classical comparative anatomy has revealed a wealth of new data concerning the musculature of the maxillules, maxillae and maxillipeds (= first thoracopods) in the Crustacea (Boxshall and Huys, 1992).

New tantulocarid, Stygotantulus stocki, parasitic on harpacticoid copepods, with an analysis of the phylogenetic relationships within the Maxillopoda.

ABSTRACT A new genus of Tantulocarida, Stygotantulus, is described based on material from an anchialine pool on Lanzarote, Canary Islands. It is the most primitive tantulocarid known and is ectoparasitic on representatives of at least two families of harpacticoid copepods. It is distinguished by the presence of 7 abdominal somites in the tantulus larva. The musculature of the penis on trunk somite 7 of the male suggests that it is derived by modification of the seventh thoracopods. The importance of trunk somite numbers in maxillopodan systematics is reexamined and an attempt is made to apply the concept of homology to the developmental processes determining somite numbers. The classification of the Crustacea, including the Tantulocarida, proposed by Starobogatov (1986), is criticized and the validity of the developmental-functional concept of the prototagma, as used by Starobogatov, is refuted. A new scheme of phylogenetic relationships among seven major maxillopodan groups is presented.

Tantulocarida, a New Class of Crustacea Ectoparasitic on other Crustaceans

ABSTRACT New species of the little known genera Basipodella Becker and Deoterthron Bradford and Hewitt are described from material collected in the Atlantic off the Azores and from the Tasman Sea. Detailed examination of all known material of Basipodella (B. harpacticola Becker, 1975, and B. atlantica, new species) and of Deoterthron aselloticola, new species, has confirmed that earlier assignments of these genera to the Copepoda and Cirripedia were incorrect. These genera represent a new class of Crustacea for which the name Tantulocarida is proposed. Tantulocarids are minute copepod-like ectoparasites of other deep-sea benthic crustaceans. Their diagnostic characters include: the lack of any recognisable cephalic appendages, the possession of a solid median cephalic stylet, six free thoracic somites, each bearing a pair of thoracopods, and six abdominal somites. The anterior five pairs of thoracopods are biramous, each has a well-developed protopod and a large endite arising from the base of the protopod. The phylogenetic relationships of the Tantulocarida are discussed.

Kabatarina pattersoni; a fossil parasitic copepod (Dichelesthiidae) from a Lower Cretaceous fish

Thirteen fragments of a fossil parasitic copepod have been recovered from two specimens of the fossil teleost fish, Cladocyclus gardneri, from the Santana Formation in Brazil. The fossil fragments are preserved in the round and represent both sexes of a primitive species of the family Dichelesthiidae, related to the modem genera Anthosoma and Dichelesthium.

The Tantulocaridan Life Cycle: the Circle Closed?

ABSTRACT The discovery of a new stage in the life cycle of the Tantulocarida is reported. A sexual female, collected from a deep-sea harpacticoid copepod host, was removed from the trunk sac of the preceding tantulus larva. This female is a free-living and nonfeeding stage which presumably mates with the free-swimming adult male previously described. The female comprises a cephalothorax, probably incorporating 2 limbless thoracic somites, 2 free pedigerous trunk somites, and 3 limbless trunk somites. It also possesses paired antennules, the only well-defined cephalic appendages present at any stage in tantulocaridan life history. There is a median genital aperture, the copulatory pore, located ventrally on the cephalothorax at about the level of the incorporated first thoracic somite. This is interpreted as further evidence of a sister-group relationship between the Tantulocarida and the Thecostraca. The known life-cycle stages of the Tantulocarida are now interpreted as forming two cycles, one sexual, the other parthenogenetic.

The Epacteriscidae, a cave-living family of calanoid copepods

Abstract Twelve genera and 20 species of epacteriscids are recorded from marine and anchialine caves in tropical and subtropical waters. Nine genera are new: Eduxiella from Jamaica; Ena111ronia from Lanzarote, the Canary Islands; Balinella, Bojitriella, Bomburiella, Enantronoides, and Oinella from the Bahamas; Gloinella from Cuba; Erebonectes macrochaetus Fosshagen from the Caicos Islands, West Indies is transferred to a new genus Erebonectoides. Six new species of Enantiosis Barr are described, one each from Bermuda, Belize, Galapagos, and Fiji, and two from Palau. Two new species of Epacteriscus Foss hagen arc described from Belize and E. rapax Fosshagen is recorded for the first time in Bermuda. New records of Erebonectes nesioticus Fosshagen are made in Bermuda and a habitat division between three species of Epacteriscus, Enantiosis and Erebonectes from Bermuda is suggested. A phylogenetic analysis of described taxa was performed using PAUP. Based on inferences from this analysis two new subfamilies are proposed: the Erebonectinae (to include Erebonectes and Erehonectoides) and the Epacteriscinae (to include all ten other genera).

Host specificity in copepod parasites of deep-sea fishes

Parasitic copepods belonging to two orders, Siphonostomatoida and Poecilostomatoida, are frequently reported from fish hosts in the deep sea. Three families of copepods are most commonly encountered, Sphyriidae, Lernaeopodidae and Chondracanthidae, but members of another four families, Hatschekiidae, Pennellidae, Philichthyidae and Hyponeoidae, are occasionally recorded. These parasites utilise various deep demersal fishes as hosts, especially species of the most abundant families, Macrouridae, Moridae, Synaphobranchidae and Alepocephalidae. Host specificity levels are variable, as for shallow-water fishes. In contrast, few parasites are regularly reported from fishes inhabiting the pelagic water column away from the bottom and away from the near-surface zone. Only the pennellids Sarcotretes scopeli and Cardiodectes medusaeus appear common on pelagic fishes, in the Atlantic and Pacific respectively. Host specificity levels in these two pennellid species are relatively low. It is speculated that the difficulty of encountering a host in the vast pelagic biome has restricted the diversity of parasitic copepods that have successfully colonized pelagic fishes.