从细胞色素b基因序列变异分析中国鲇形目鱼类的系统发育

采用PCR技术获得中国鲇形目鱼类11科24属27个代表种类细胞色素b基因1138bp全序列,比较分析了来自北美洲、非洲的部分鲇形目鱼类同一基因序列,并选取脂鲤目、鲤形目和鲱形目鱼类作外类群,采用Bayesian方法和最大简约法(MP)构建分子系统树。结果表明：(1)鲇形目鱼类细胞色素b基因序列中,与脂鲤目、鲤形目以及鲱形目鱼类相比存在3bp的缺失;(2)鲇形目鱼类各科代表种类形成一单系群;(3)两种建树方法均支持铫科、粒鲇科和钝头鮠科形成一单系群;而胡子鲇科、刀鲇科、海鲇科、鮰科、长臀鮠科、鲢科、鲇科、棘脂鲿科、鲿科形成一大的单系群;但鳗鲇科的系统位置两种建树方法没有取得一致结果;而其中长臀鲍科与北美的鮰科形成姐妹群,胡子鲇、鮰科、鲇科、鲿科和鮡科是较明显的单系群。     

The phylogenetic relationships among non-diplomystid catfishes as inferred from mitochondrial cytochrome b sequences; the search for the ictalurid sister taxon (Otophysi: Siluriformes)

The relationships among families of catfishes are poorly understood and have yet to be the subject of a comprehensive investigation with molecular data. Existing phylogenetic hypotheses are based on morphological data and incompletely resolved. This study analyzed complete sequences of mitochondrial gene cytochrome b for 170 species from 29 of 33 extant families, and focused on the relationships of Ictaluridae to other catfishes. In addition to previous phylogenetic studies, the fossil record, paleogeography, biogeography, and distribution of extant catfish families collectively suggest the location (if extant) of the ictalurid sister taxon to be Northern or Eastern Asia. Of the extant catfishes currently native to this area and included in this analysis, parsimony and Bayesian likelihood analyses recovered Cranoglanis bouderius as the most proximal sister taxon of Ictaluridae. Seemingly, ictalurids and cranoglanidids represent another biogeographic component linking freshwater fishes of North America and eastern Asia, e.g., catostomids and paddlefishes. The results coupled with present-day catfish distributions and inferences from the fossil record collectively suggest the ancestor of Ictaluridae to have invaded freshwaters of North America at the close of the Cretaceous through northeastern Asia and northwestern North America. Other superfamilial nodes supported the results of previous phylogenetic studies of narrower taxonomic scope. Several novel relationships were recovered (including a clade composed of Pimelodidae, Pseudopimelodidae, and Heptapteridae) and these along with sources of systematic error are discussed. A broad sampling of Bagridae permitted an examination of intergeneric relationships within this family and in light of recent morphological and molecular studies.     

Sperm of Doradidae (Teleostei: Siluriformes)

Spermatic characteristics were studied in 10 species representing several distinct groups within the catfish family Doradidae. Interestingly, different types of spermatogenesis, spermiogenesis and spermatozoa are correlated with intrafamilial groups previously proposed for Doradidae. Semi-cystic spermatogenesis, modified Type III spermiogenesis, and biflagellate sperm appear to be unique within Doradidae to the subfamily Astrodoradinae. Other doradid species have sperm with a single flagellum, cystic spermatogenesis, and spermiogenesis of Type I (Pterodoras granulosus, Rhinodoras dorbignyi), Type I modified (Oxydoras kneri), or Type III (Trachydoras paraguayensis). Doradids have an external mode of fertilization, and share a few spermatic characteristics, such as cystic spermatogenesis, Type I spermiogenesis and uniflagellate sperm, with its sister group Auchenipteridae, a family exhibiting sperm modifications associated with insemination and internal fertilization. Semi-cystic spermatogenesis and biflagellate spermatozoa are also found in Aspredinidae, and corroborate recent proposals that Aspredinidae and Doradoidea (Doradidae + Auchenipteridae) are sister groups and that Astrodoradinae occupies a basal position within Doradidae. The co-occurrence in various catfish families of semi-cystic spermatogenesis and either biflagellate spermatozoa (Aspredinidae, Cetopsidae, Doradidae, Malapturidae, Nematogenyidae) or uniflagellate sperm with two axonemes (Ariidae) reinforces the suggestion that such characteristics are correlated. Semi-cystic spermatogenesis and biflagellate sperm may represent ancestral conditions for Loricarioidei and Siluroidei of Siluriformes as they occur in putatively basal members of each suborder, Nematogenyidae and Cetopsidae, respectively. However, if semi-cystic spermatogenesis and biflagellate sperm are ancestral for Siluriformes, cystic spermatogenesis and uniflagellate sperm have arisen independently in multiple lineages including Diplomystidae, sister group to Siluroidei.     

Comparative biochemical studies of carotenoids in catfishes

The carotenoids of 12 species of Siluriformes fishes (eight families) were investigated from a comparative biochemical point of view. The patterns of carotenoids in catfishes belonging to the family Siluridae were quite different from those of the other seven families of catfishes (Bagridae, Amblycipitidae, Clariidae, Plotosidae, Ictaluridae, Callichthyidae and Malapteruridae). 7, 8-Dihydro-beta-carotene; 7, 8, 7', 8'- and 7, 8, 9, 10-tetrahydro-beta-carotene; (3R)-7', 8'-dihydro-beta-cryptoxanthin; 7, 8-dihydrolutein A; 7, 8-dihydrolutein B; parasiloxanthin; 7', 8'-dihydroparasiloxanthin; and 4 or 4'-hydroxyparasiloxanthin were characteristic carotenoids found in only one family, Siluridae, and these carotenoids accounted for 24-60% of total carotenoids. In catfishes belonging to the other seven families except Siluridae, the carotenoid patterns were very similar and the most predominant carotenoid was zeaxanthins (23-56%).     

The complete mitochondrial DNA sequence of the Mekong giant catfish (Pangasianodon gigas), and the phylogenetic relationships among Siluriformes

The Mekong giant catfish (Pangasianodon gigas) is the largest scale-less freshwater fish of the world, and a critically endangered species. We determined the complete nucleotide sequence (16,533 bp) of the mitochondrial genome of the Mekong giant catfish, and conducted phylogenetic analyses based on mitochondrial protein (the combined amino acid sequences of all 13 mitochondrial protein coding genes) and rRNA (the combined nucleotide sequences of mitochondrial 12S and 16S rRNA genes) data sets in order to further clarify the relative phylogenetic position of P. gigas, and to recover phylogenetic relationships among 15 out of the 33 families of Siluriformes. Phylogenetic analyses (maximum parsimony, minimum evolution, maximum likelihood, Bayesian inference) of the protein data set were congruent with a basal split of the order into Loricarioidei and Siluroidei, and supported a closer relationship of the Mekong giant catfish (family Pangasiidae) to Siluridae than to Bagridae. The rRNA-based Bayesian phylogeny recovered Callichthyidae as the sister group of all other analyzed non-diplomystid catfish families, rendering Loricarioidei paraphyletic. In addition, Loricariidae were recovered as paraphyletic due to the inclusion of Astroblepidae. However, none of the two relationships received bootstrap support in the maximum parsimony, minimum evolution, and maximum likelihood analyses, and should be interpreted with caution. The derived position of Cetopsidae within Siluroidei, the sister group relationship of Pseudopimelodidae and Pimelodidae, and a close relationship of Doradidae and Auchenipteridae to the exclusion of Mochokidae were strongly supported. Pangasiidae was placed as a single lineage without clear affinities.     

Occurrence of biflagellate spermatozoa in Cetopsidae, Aspredinidae, and Nematogenyidae (Teleostei: Ostariophysi: Siluriformes)

In the present study spermiogenesis was investigated in Cetopsis coecutiens (Cetopsidae), and Bunocephalus amazonicus (Aspredinidae), while spermatozoa ultrastructure was investigated in C. coecutiens, B. amazonicus, and Nematogenys inermis (Nematogenyidae). Aspredinidae and Cetopsidae share a spermatogenesis of the semicystic type, and a particular type of spermiogenesis process not reported in any fish group. In the three species analyzed, spermatozoa are biflagellate with flagella having the classical axoneme formulae (9 + 2). The analysis of thirteen characters showed the presence of eight characters shared by Cetopsidae and Aspredinidae, and six characters shared by Cetopsidae and Nematogenyidae, which may suggest that these three families may be more related than actually hypothesized, comprising a very primitive siluriform lineage originated after Diplomystidae.     

Karyology of the marine catfishBagre marinus (Ariidae) with an analysis of chromosome numbers among siluriform fishes

Bagre marinus has a diploid complement of 54 chromosomes composed of 12 metacentrics, 8 submetacentrics, and the remainder with terminal or near-terminal centromeres. Karyotypes for three species of ariid catfishes (Arius dussumieri, A. felis, andBagre marinus) indicate the same diploid number, but each species has a different arm number. Data for 132 species in 14 families of catfishes show a predominance of 56±2 chromosomes in the diploid set. This range in diploid number is most common in the Ariidae, Bagridae, Ictaluridae, and Pimelodidae, which, together with the Doradidae (no karyotypes available), have been suggested, from osteology, as forming a group close to ancestral stock from which living catfishes evolved.     

The complete mitochondrial genome of the helmet catfish Cranoglanis bouderius (Siluriformes: Cranoglanididae) and the phylogeny of otophysan fishes

The complete sequence of the 16,539 nucleotide mitochondrial genome from the single species of the catfish family Cranoglanididae, the helmet catfish Cranoglanis bouderius, was determined using the long and accurate polymerase chain reaction (LA PCR) method. The nucleotide sequences of C. bouderius mitochondrial DNA have been compared with those of three other catfish species in the same order. The contents of the C. bouderius mitochondrial genome are 13 protein-coding genes, two ribosomal RNA and 22 transfer RNA genes, and a non-coding control region, the gene order of which is identical to that observed in most other vertebrates. Phylogenetic analyses for 13 otophysan fishes were performed using Bayesian method based on the concatenated mtDNA protein-coding gene sequence and the individual protein-coding gene sequence data set. The competing otophysan topologies were then tested by using the approximately unbiased test, the Kishino-Hasegawa test, and the Shimodaira-Hasegawa test. The results show that the grouping ((((Characiformes, Gymnotiformes), Siluriformes), Cypriniformes), outgroup) is the most likely but there is no significant difference between this one and the other alternative hypotheses. In addition, the phylogenetic placement of the family Cranoglanididae among siluriform families was also discussed.     

Structure and function in the catfish

The catfish (Siluroidei) appear to have evolved from an ancestor which, in most respects other than the form of its teeth, resembled primitive Characinoidei. In the first part of this paper it is shown that most of the numerous and profound anatomical changes which have occurred in the course of their evolution from this ancestor can be related to one or other of three basic changes: depression of the body in adaptation to bottom-feeding habits, sensory modification in adaptation to nocturnal habits, and the evolution of defensive fin spines. Diplomystes is more primitive than other known catfish in the form of its maxilla and pectoral girdle, and in the posterior position of its dorsal fin.
The second part of the paper is concerned with some of the more specialized families of catfish (Mochokidae, Siluridae, Schilbeidae, Malapteruridae, Clariidae, Callichthyidae and Loricariidae). The specializations in each case are described, and related to the habits of the fish.     

Osteology and myology of the cephalic region and pectoral girdle of the Chinese catfish Cranoglanis bouderius,with a discussion on the autapomorphies and phylogenetic relationships of the Cranoglanididae (Teleostei: Siluriformes)

The cephalic and pectoral girdle structures of the Chinese catfish Cranoglanis bouderius are described and compared with those of other catfishes as the foundation for an analysis on the Cranoglanididae autapomorphies and also for a discussion on the phylogenetic relationships between the cranoglanidids and the other catfishes. Our observations and comparisons indicate that cranoglanidids are defined, at least, by four autapomorphies, namely: 1) the cartilages associated with the mandibular barbels are broad, somewhat circular; 2) epioccipital with a well-developed posterodorsal process, which presents a large, deep, circular posterior concavity; 3) a well-defined, deep, anteroposteriorly elongated concavity formed by both the frontal and the lateral ethmoid to receive the anteromedial surface of the metapterygoid; 4) the adductor mandibulae A3" is dorsally divided into two bundles and partially inserted on the posterior portion of the primordial ligament. With respect to the phylogenetic relationships of the Cranoglanididae, this study strongly suggests that these fishes are probably closely related to the Ariidae and the Claroteidae.     

我国鲇形目鱼类的地理分布

根据最新的分类系统(Nelson,1984),鲇形目鱼类包括31个科,二千余种。它们的分布几乎是全球性的,多数生活在淡水中;只有海鲇科和鳗科主要生活在海洋里,     

Osteology and myology of the cephalic region and pectoral girdle of Erethistes pusillus, comparison with other erethistids, and comments on the synapomorphies and phylogenetic relationships of the Erethistidae (Teleostei: Siluriformes)

The cephalic and pectoral girdle structures of the erethistid Erethistes pusillus (Erethistinae) are described and compared with those of another species of the subfamily Erethistinae, namely Hara filamentosa , and of the single species of the subfamily Continae, Conta conta , as well as of several other catfishes, as the foundation for a discussion on the synapomorphies and phylogenetic position of the Erethistidae. The observations and comparisons support de Pinna's phylogenetic hypothesis, according to which the Erethistidae is the sister‐group of the Aspredinidae, with the clade formed by these two families being the sister‐group of the Sisoridae sensu stricto . In addition, the observations and comparisons pointed out a new, additional character to diagnose the family Erethistidae, namely: mesocoracoid arch deeply bifurcated dorsally.     

Relationships among characiform fishes inferred from analysis of nuclear and mitochondrial gene sequences

Suprafamilial relationships among characiform fishes and implications for the taxonomy and biogeographic history of the Characiformes were investigated by parsimony analysis of four nuclear and two mitochondrial genes across 124 ingroup and 11 outgroup taxa. Simultaneous analysis of 3660 aligned base pairs from the mitochondrial 16S and cytochrome b genes and the nuclear recombination activating gene (RAG2), seven in absentia (sia), forkhead (fkh), and alpha-tropomyosin (trop) gene loci confirmed the non-monophyly of the African and Neotropical assemblages and corroborated many suprafamilial groups proposed previously on the basis of morphological features. The African distichodontids plus citharinids were strongly supported as a monophyletic Citharinoidei that is the sistergroup to all other characiforms, which form a monophyletic Characoidei composed of two large clades. The first represents an assemblage of both African and Neotropical taxa, wherein a monophyletic African Alestidae is sister to a smaller clade comprised of the Neotropical families Ctenolucidae, Lebiasinidae, and the African Hepsetidae, with that assemblage sister to a strictly Neotropical clade comprised of the Crenuchidae and Erythrinidae. The second clade within the Characoidei is strictly Neotropical and includes all other Characiformes grouped into two well supported major clades. The first, corresponding to a traditional definition of the Characidae, is congruent with some groupings previously supported by morphological evidence. The second clade comprises a monophyletic Anostomoidea that is sister to a clade formed by the families Hemiodontidae, Parodontidae, and Serrasalmidae, with that assemblage, in turn, the sistergroup of the Cynodontidae. Serrasalmidae, traditionally regarded as a subfamily of Characidae, was recovered as the sistergroup of (Anostomoidea (Parodontidae+Hemiodontidae)) and the family Cynodontidae was recovered with strong support as the sistergroup to this assemblage. Our results reveal three instances of trans-continental sistergroup relationships and, in light of the fossil evidence, suggest that marine dispersal cannot be ruled out a priori and that a simple model of vicariance does not readily explain the biogeographic history of the characiform fishes.     

Unculi (Horny Projections Arising from Single Cells), an Adaptive Feature of the Epidermis of Ostariophysan Fishes

Horny projections arising from single cells, or unculi, of ostariophysan fishes are described and discussed by several workers, but they occur in many more families and genera than previously reported and their status as a key adaptive feature has not been recognized. Unculi are related morphologically to the relatively well-known multicellular horny tubercles (including breeding tubercles) of Ostariophysi and other fishes, but differ from them in anatomical distribution and function. Unculi are especially prominent features of portions of the epidermis in Cyprinoidei (carps, loaches, and their allies) and Siluroidei (catfishes); they also occur in Characoidei (characins) and Chanoidei (gonorynchs) but have not been found in any non-ostariophysan fishes. Unculi evidently are functionally significant on the lips and other mouth parts (especially in groups lacking jaw teeth), on the ventral surface of the paired fins in many bottom-dwellers, and on several neomorphic features including epidermal plaques and tubercles in various catfishes, the thoracic adhesive disc of sisorid catfishes, and the mental adhesive disc of the cyprinid genus Garra . In some sisorid and akysid catfishes virtually the entire external body surface is covered by unculiferous plaques or tubercles. Possible functions of unculi include: mechanical protection of the skin, rasping, adhesion, and hydrodynamic effects. Unculi seem to have been especially important in the diversification of cyprinoid feeding habits and in the adaptation of bottom-dwelling cyprinoids and siluroids to swift-water habitats, especially in Asia.     

Phylogeny of the Amphiliidae (Teleostei: Siluriformes)

The freshwater African catfish family Amphiliidae had been reviewed based on the 73 osteological characters with Diplomystidae, 2 Hypsidoridae, Amblycipitidae, Sisoridae, and Bagridae as out-groups. Because the family position of Leptoglanis (Bagridae/Amphiliidae) is under debate, this genus has been taken as an out-group too. Results of the study indicate that: 1) the Amphiliidae is not a monophyletic group and must now be restricted to the genera Amphilius and Paramphilius; the two subfamilies Amphiliinae and Doumeinae are separated by the sisorids Euchiloglanis (with most of the glyptosternid fishes) and Glyptothorax (with most of the non-glyptosternid fishes); 2) no synapomorphies were found for the subfamily Amphiliinae. 3) The five genera of subfamily Doumeinae constitute a monophyletic group, Andersonia being the sister-group of the four other genera; subfamily Doumeinae + Leptoglanis form the family Doumeidae. The glyptosternids no longer belong to the Sisoridae (family restricted to the non-glyptosternids) and represent the new family Glyptosternidae.     

Spermiogenesis and sperm ultrastructure in ten species of Loricariidae (Siluriformes, Teleostei)

The current study describes the ultrastructural characteristics of spermatogenesis, spermiogenesis, and spermatozoa in specimens of siluriform taxa Neoplecostominae, Hypoptopomatinae, Otothyrinae, Loricariinae, and Hypostominae. Our data show that the characteristics of spermatogenesis and spermiogenesis and spermatozoa ultrastructure of Neoplecostominae are more common to Hypoptopomatinae and Otothyrinae than to Loricariinae and Hypostominae. Furthermore, Loricariinae and Hypostominae have more characteristics in common than with any other group of Loricariidae. These data reinforce the phylogenetic hypotheses of relationships among the subfamilies of Loricariidae. Considering the available data in Loricarioidei, Loricariidae presents ultrastructural characteristics of spermatogenesis and spermiogenesis that are also observed in Astroblepidae, its sister group. However, the most of the characteristics of spermatozoa ultrastructure found in Astroblepidae are also observed in Scoloplacidae, the sister group of a clade composed of Astroblepidae and Loricariidae.     

Phylogeny of the African representatives of the catfish family Clariidae (Teleostei, Siluriformes) based on a combined analysis: independent evolution towards anguilliformity

Clariid catfishes span a broad range of body forms ranging between fusiform and anguilliform morphotypes. Although such variation in body shape has been observed in other families of teleost fishes, amphibians and reptiles, it is rarely as extreme as within the Clariidae. Although the Clariidae were thought to have undergone anagenetic evolution (i.e. progressive evolution within a lineage), more recent studies indicate that anguilliformity evolved several times through a process of cladogenesis (i.e. branching of evolutionary lineages). In this study, it is shown that the phylogenetic analysis of morphological data mainly gives a reflection of the cranial evolution in the Clariidae despite the use of 18 post-cranial characters (out of a total of 53 characters). A combined phylogenetic analysis of both morphological and molecular data rather suggests the derived nature of body elongation. The corresponding morphological changes that co-occur with this elongation can be regarded as an extreme case of convergent evolution at the genus level within the Clariidae.     

A new genus and species of proteocephalidean (Cestoda) from Clarias catfishes (Siluriformes: Clariidae) in Africa

A new proteocephalidean cestode is described from 2 catfishes, Clarias gariepinus (type host) and C. cf. anguillaris (Siluriformes: Clariidae), from Ethiopia (type locality), Sudan, Tanzania, and Zimbabwe, and a new genus, Barsonella, is proposed to accommodate it. The genus belongs to the Proteocephalinae because its genital organs (testes, ovary, vitellarium, and uterus) are situated in the medulla. Barsonella lafoni, the type and only species of the new genus, is characterized mainly by the possession of an additional opening of each sucker; circular musculature on the anterior margin of suckers, serving as a sphincter; a small thin-walled glandular apical organ; absence of well-developed osmoregulatory canals in mature, pregravid, and gravid proglottids; and a large strobila, up to 173 mm long and 3.2 mm wide. Species of Marsypocephalus Wedl, 1861 (Marsypocephalinae), other large-sized proteocephalidean tapeworms occurring sympatrically in African catfishes (Clarias and Heterobranchus) and also possessing a sphincter-like, circular musculature on the anterior part of suckers, differ from B. lafoni in the absence of an additional sucker opening and glandular apical organ, the cortical position of the testes, well-developed osmoregulatory canals throughout the strobila, and a large cirrus sac. Proteocephalus glanduligerus (Janicki, 1928), another cestode parasitic in Clarias spp. in Africa, is much smaller than B. lafoni (maximum length 15 mm), has suckers without additional opening and circular musculature on the suckers, a large-sized glandular organ, much larger than suckers, and well-developed osmoregulatory canals. Comparison of partial sequences of the 28S rRNA gene for 7 samples of B. lafoni from 2 different hosts and 4 localities in Ethiopia, Sudan, and Tanzania has shown a very low genetic variability. In a limited phylogenetic analysis, B. lafoni formed a clade with Corallobothrium solidum Fritsch, 1886 (Proteocephalidae: Corallobothriinae), an African electric catfish parasite. This clade was the sister group of almost all Neotropical taxa from pimelodid and other catfishes.     

Convergence among cave catfishes: long-branch attraction and a Bayesian relative rates test

Convergence has long been of interest to evolutionary biologists. Cave organisms appear to be ideal candidates for studying convergence in morphological, physiological, and developmental traits. Here we report apparent convergence in two cave-catfishes that were described on morphological grounds as congeners: Prietella phreatophila and Prietella lundbergi. We collected mitochondrial DNA sequence data from 10 species of catfishes, representing five of the seven genera in Ictaluridae, as well as seven species from a broad range of siluriform outgroups. Analysis of the sequence data under parsimony supports a monophyletic Prietella. However, both maximum-likelihood and Bayesian analyses support polyphyly of the genus, with P. lundbergi sister to Ictalurus and P. phreatophila sister to Ameiurus. The topological difference between parsimony and the other methods appears to result from long-branch attraction between the Prietella species. Similarly, the sequence data do not support several other relationships within Ictaluridae supported by morphology. We develop a new Bayesian method for examining variation in molecular rates of evolution across a phylogeny.