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The ancient catfish family Diplomystidae, with seven species endemic to rivers of southern South America, represents one of the oldest branches of the diverse order Siluriformes. With most species endangered, new reports of these species become extremely valuable for conservation. Currently, it is assumed that Diplomystes species inhabit only Andean (large) basins, and that they are extinct from coastal (small) basins from which their presence have not been recorded since 1919. Here, we document new records of the family Diplomystidae in the Laraquete and Carampangue basins, two coastal basins from the Nahuelbuta Coast Range, Chile, with no previous reports. This finding represents the rediscovery of the genus in coastal basins in more than a Century. Based on analysis of mitochondrial DNA sequences, the collected specimens were found to be closely related to Diplomystes nahuelbutaensis from the Andean Biobío Basin, but sufficiently differentiated to suggest that coastal basin populations are a different management unit. These populations are important because, contrary to previous thoughts, they prove these catfish can survive in small river networks, providing unique opportunities for research and conservation. The conservation category of Critically Endangered (CE) is recommended for the populations from the Laraquete and Carampangue basins. RESUMEN La familia de bagres Diplomystidae, con siete especies endémicas de ríos del sur de Sudamérica, es uno de los linajes mas antiguos del diverso orden Siluriformes. Al estar la mayoría de las especies amenazadas, nuevos registros de éstas son extremadamente valiosos para su conservación. Actualmente, se ha asumido que los Diplomystidos se distribuyen solo en cuencas Andinas (más grandes), y que sus especies estarían extintas en cuencas de menor tamaño como las costeras, sin registros desde 1919. En este trabajo documentamos la familia Diplomistidae en las cuencas de Carampangue y Laraquete, dos cuencas costeras de la Cordillera de Nahuelbuta, Chile, lo que representa el primer registro de esta familia en estas cuencas costeras. Además, este hallazgo representa el re-descubrimiento de la familia en cuencas costeras después de un siglo. Sobre la base de análisis de ADN mitocondrial, los especímenes colectados se relacionaron más cercanamente con poblaciones de la especie Diplomystes nahuelbutaensis presente en la cuenca del Biobío. Sin embargo, existen diferencias genéticas suficientes entre las poblaciones costeras y las del Biobío para justificar su separación como unidad de manejo distinta. Estas poblaciones costeras son importantes porque demuestran que los Diplomístidos pueden sobrevivir en cuencas de pequeño tamaño, ofreciendo oportunidades únicas para su investigación y conservación. Se recomienda la categoría de conservación En Peligro Critico de Extinción (CR) para las poblaciones de las cuencas Laraquete y Carampangue.

Catfishes (Teleostei: Siluriformes) are a highly diverse order within Ostariophysi that is distributed worldwide. At the base of this clade emerge three lineages with well-defined monophylies: Diplomystidae, Loricarioidei, and Siluroidei. Morphological phylogeny studies place the Diplomystidae as the earliest branching of these three lineages, but studies based on molecular phylogenetics consistently find the fast-evolving Loricarioidei instead. The high lineage evolutionary rate heterogeneity in this order and the fact that the lineage placed closest to the root in the molecular phylogenies is fast evolving, including many long branches, raises the possibility that the discrepancy between morphological and molecular phylogenies may be the result of a long branch attraction inference artifact. We test this hypothesis by using a 10-gene dataset to evaluate the arrangement of the three main siluriform lineages, and apply the LS3 and LS4 taxon sequence subsampling methods to reduce evolutionary rate heterogeneity among lineages. The initial and complete dataset supports the basal branching of Loricarioidei as in all previous molecular phylogenies, but once lineage rate heterogeneity is reduced with LS3 or LS4 through the removal of sequences disrupting homogeneity, the phylogeny shows Diplomystidae as the earliest branching group, with high supports, as proposed by morphological phylogeny. The result obtained with LS3, however, introduces the misplacement of one of the species with the highest amount of missing data, Scoloplax sp. Because the sequence sub-selection criterion of LS4 has been optimized to reduce data removal, the phylogeny resulting from the LS4-processed data is in agreement with the known intra-lineage relationships in addition to supporting the morphologically-based rooting hypothesis. Our results are the first instance in which a consensus between molecular and morphological phylogeny is reached concerning the root of this order.

A specimen of a remarkable new catfish genus and species was collected in middle/late Miocene marine beds of the Puerto Madryn Formation at the base of the marine cliff of the sea lion colony area near Puerto Pirámide, southern coast of Península Valdés, northeastern Patagonia, Argentina. Siluriforms (catfishes) constitute a most important monophyletic ostariophysan group of mainly freshwater fishes that occurs in almost all continents but it is especially diverse in South America. Catfishes are presently distributed in tropical to temperate areas and a small number of species are marine or amphibiotic. The new catfish shows many primitive features for catfishes in the maxilla, autopalatine, hyal elements, and Weberian apparatus. The genus is clearly distinguished by four autapomorphies: sand clock–shaped autopalatine, posterior limb of autopalatine widening strongly, post-articular arm of autopalatine longer, and a metapterygoid longer than broad. One tree was obtained both under equal and implied weighting with the following topology: a basal polytomy in the Siluriformes formed by Diplomystidae, Bachmanniidae, Kooiichthys and the Siluroidei. The new species appears to have been a marine or amphibiotic taxon: it was collected in beds considered to represent the Maximum Flooding Horizon of the transgression that deposited the Puerto Madryn Formation. The coast at this moment was at approximately 90 km to the west. According to faunistic evidence, the sea was warm temperate.

Dental structures originally emerged as components of the exoskeleton of ancestral vertebrates. Throughout evolution, these structures started being built inside the oral cavity, allowing these ancestral vertebrates to switch to a more predatory lifestyle and opening a vast diversity of new ecological niches. However, to date, the evolutionary and developmental processes by which dental structures can be built in new areas of the body plan are not clear. One of the main limitations for investigating this question is the lack of informative model organisms that show a clear gain of dental structures in new areas of the body. In this study, I focus my studies on catfish (Teleostei: Silurifomes): a highly diverse group of fish that contains a lineage of denticulate catfish (Loricarioidei) in which dental structures presumably emerged de novo on extra-oral body surfaces. I use the Loricarioidei to study the evolutionary and developmental mechanisms through which dentition can be built in new areas of the vertebrate body plan. Because this lineage has never been studied in the context of dental evolution, I must take a multidisciplinary approach at this question to have a broad perspective of the factors related to the gain of dental structures in the loricarioid body. In this work I integrate information that I recovered through studies in the fields of molecular phylogenetics, morphology, evolutionary biology and developmental biology. I begin by determining the phylogenetic landscape in which these denticles emerged, and start by placing the Loricarioidei within the catfish phylogeny. However, the fast molecular evolution of this group and the general diversity of evolutionary rates among catfish species raise methodological challenges for inferring this phylogeny correctly. I address these challenges and propose two new methods, LS³ and LS⁴, to improve any phylogeny inference in which extreme heterogeneous evolutionary rates may be a source of bias. I apply LS⁴ as implemented in a software I produced for this work, LSX, on a new molecular dataset to address the position of the Loricarioidei, and I am able to place this lineage nested within Siluriformes, among groups of catfish that have a naked skin. These results confirm that dental structures indeed emerged de novo in the extra-oral regions of loricarioids. I then ask if the evolutionary emergence of the loricarioid denticles was linked to the formation of other bony elements observed in this lineage, such as dermal bony plates. Through ancestral state reconstruction, I find that the emergence of loricarioid denticles was not linked in evolution to the emergence of dermal bony plates, but that an underlying superficial bone is likely essential for the formation of these dental structures. In the final section of this work I enter into the developmental mechanisms through which these de novo dental structures are built. I use the species Ancistrus triradiatus, which is the new model loricarioid catfish species developed in the laboratory of Juan Montoya-Burgos. Through in situ hybridization and immunostaining studies, I find that loricarioid denticles, despite being an independent emergence of dental structures in new body areas, are produced by deploying the same developmental genetic program that produces oral teeth in other vertebrates. This indicates that dental structures found inside and outside the oral cavity in this loricarioid model species are homologous. In view of these results I conclude that it is possible for vertebrates to gain dental structures in new areas of the body through the cooption of the oral tooth developmental program.

Made available in DSpace on 2013-09-27T14:54:34Z (GMT). No. of bitstreams: 1 WOS000288637500002.pdf: 4001569 bytes, checksum: e51767abb616d45441648163a1275fea (MD5) Previous issue date: 2011-02-01 Made available in DSpace on 2013-09-30T18:39:54Z (GMT). No. of bitstreams: 1 WOS000288637500002.pdf: 4001569 bytes, checksum: e51767abb616d45441648163a1275fea (MD5) Previous issue date: 2011-02-01 Submitted by Vitor Silverio Rodrigues (vitorsrodrigues@reitoria.unesp.br) on 2014-05-20T13:52:32Z No. of bitstreams: 1 WOS000288637500002.pdf: 4001569 bytes, checksum: e51767abb616d45441648163a1275fea (MD5) Made available in DSpace on 2014-05-20T13:52:32Z (GMT). No. of bitstreams: 1 WOS000288637500002.pdf: 4001569 bytes, checksum: e51767abb616d45441648163a1275fea (MD5) Previous issue date: 2011-02-01 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) 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 Ill 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. (C) 2010 Elsevier Ltd. All rights reserved. Univ Estadual Paulista, Dept Morfol, Inst Biociencias, BR-18618970 São Paulo, Brazil UNESP, Inst Biociencias Botucatu, Grad Program Zool, Botucatu, SP, Brazil Acad Nat Sci Philadelphia, Dept Ichthyol, Philadelphia, PA 19103 USA Univ Estadual Paulista, Dept Morfol, Inst Biociencias, BR-18618970 São Paulo, Brazil UNESP, Inst Biociencias Botucatu, Grad Program Zool, Botucatu, SP, Brazil

Karyotypes of Diplomystes composensis and Diplomystes nahuelbutaensis were the same diploid number (n= 56).The chromosome formula for D. composensis was 16 metacentric + 24 submetacentric + 8 subtelocentric + 8 telocentric chromosomes and for D. nahuelbutaensis was 14 metacentric + 26 submetacentric + 8 subtelocentric +8 telocentric chromosomes. In contrast, the differences in the chromosomal C-banding patterns between these species was large. For instance, chromosome pairs 5,6, and 7 of D. nahuelbutaensis showed heterochromatic centromeres and pairs 23, 24, 27, and 28 were entirely heterochromotic. Diplomystes composensis showed conspicuous C-banded blocks in pairs 7, 24, and 25 (chromosome pair 7 had one heterochromatic arm, chromosome pair 24 was entirely heterochromatic, and chromosome pair 25 had heterochromatin close to centromere). Comparison with other ostariophysan karyotypes (e.g. gymnotiforms, characiforms, and cypriniforms), does not allow any conclusions about the ploesiomorphic catfish condition, because the karyotypes of the outgroups are too variable. A synapomorphy shared by characiforms, gymnotiforms, and diplomystid catfishes is the presence of more metacentric to submetacentric than substelocentric to telocentric chromosomes. Cypriniforms are more primitive because they have more subtelocentric to telocentric than metacentric to submetacentric chromosomes.

Spadella, M. A., Oliveira, C. and Quagio-Grassiotto, I. 2006. Spermiogenesisand introsperm ultrastructure of Scoloplax distolothrix (Ostariophysi: Siluriformes:Scoloplacidae). — Acta Zoologica (Stockholm) 87 : 341–348Spermiogenesis in scoloplacids is characterized by initial lateral developmentof the flagellum, nuclear rotation, medial nuclear fossa formation, complexcentriolar migration, and cytoplasmic channel formation. The scoloplacidspermiogenesis is similar to those found in Diplomystidae, the most primitivesiluriform family. The scoloplacid spermatozoa have all the main characteristicsof introsperm. They exhibit a conic head, a symmetric midpiece, a medialflagellum, and no acrosome. The conic forward-elongated nuclei containhomogeneous chromatin. The thin extremity of the nuclei is strongly curvedand along its internal face there is a well-developed membranous compartment.The centrioles are completely inside the medial nuclear fossa, perpendicular toeach other and with an electron-dense material between them. In a cross viewof the midpiece, the mitochondria form a ring surrounding internally thecytoplasmic channel, and in a longitudinal view they are organized in a rowalong it. Several elongated vesicles are distributed peripherally, mainlyconcentrated in the mid-piece basal region. The flagellum contains the classicalaxoneme (9 + 2) and has two lateral projections or fins. The spermatozoa ofscoloplacids share several characteristics with those of Auchenipteridae. Sincethese two families are not phylogenetically related this similarity seems to bedue to convergence once both families are, until now, the only known siluriformfamilies with introsperm.Dr Irani Quagio-Grassiotto, Departamento de Morfologia, Instituto de Biociencias, Universidade Estadual Paulista, Campus de Botucatu., 18.618-000, CP 510, Distrito de Rubiao Jr, Botucatu, Sao Paulo, Brazil. E-mail: morfologia@ibb.unesp.br

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.

Family Diplomystidae Eigenmann 1890 Diplomystidae Eigenmann 1890a:12 [ref. 31918] (family) Diplomystes, Published as part of Laan, Richard Van Der, Eschmeyer, William N. & Fricke, Ronald, 2014, Family-group names of Recent fishes, pp. 1-230 in Zootaxa 3882 (2) on page 49, DOI: 10.11646/zootaxa.3882.1.1, http://zenodo.org/record/7047777, {"references":["Eigenmann, C. H. & Eigenmann, R. S. (1890) A revision of the South American Nematognathi or cat-fishes. Occasional Papers California Academy of Sciences, 1, 1 - 508 + errata and map. [July, ref. 12251] http: // dx. doi. org / 10.5962 / bhl. title. 30137","Eigenmann, C. H. (1890 a) The evolution of catfishes. Zoe, A Biological Journal, 1 (1), 10 - 15. [March, ref. 31918]"]}

Laan, Richard Van Der, Eschmeyer, William N., Fricke, Ronald (2014): Family-group names of Recent fishes. Zootaxa 3882 (2): 1-230, DOI: http://dx.doi.org/10.11646/zootaxa.3882.1.1, URL: http://dx.doi.org/10.11646/zootaxa.3882.1.1

Barbels are a general characteristic of Siluriformes, responsible for their popular name "catfish". Among the three types of catfish barbels - mandibular, maxillar and nasal - the maxillary ones are characterized by their connection to a mobile mechanism, the palatine-maxillary system (PMS). Siluriform sister-groups (Gymnotiformes and Characiformes) do not have barbels at all and do not present any structure prefiguring barbels, particularly the maxillary barbels, which are the only ones present in the most primitive catfishes, the diplomystids. So, in the absence of well preserved fossils, a gap remains between the diplomystids and the other ostariophysans. However, starting from the Diplomystidae, it seems possible to hypothesise evolutionary lines leading to more specialised PMS types. The present paper focuses on the evolution of the PMS among catfish. For each morphological transformation, the way it was realised is hypothesized and the probable adaptive advantage it brings is analysed.

A second species of the genus †Hypsidoris is described from the primitive catfish family †Hypsidoridae. The new species is from Eocene freshwater deposits of the Clamo Formation of central Oregon and is known by numerous well-preserved skeletons. Like the type species from the Green River Formation of Wyoming, the Oregon species has a well-developed toothed maxilla, a feature thought to be primitive among catfishes. Among the more than 35 nominal families containing over 2,200 species of catfishes, only Diplomystidae and †Hypsidoridae have well-developed toothed maxillae. The relationships of †Hypsidoridae to other catfishes are briefly reviewed. The associated ichthyofauna is also briefly discussed in context with other Eocene faunas of western North America.

Narrow, simple cephalic sensory canals enclosed by bone represent the primitive condition found in catfishes (siluroids) such as Diplomystidae, †Hypsidoridae, and Ictaluridae. Derived conditions among siluroids include highly branched (e.g., †Andinichthys, Galeichthys, and Parapimelodus) and reduced (e.g., trichomycterids) canals. The large bone usually termed as the supraoccipital in siluroids is thought to be homologous with the parietals + supraoccipital of other ostariophysans based on position, sutures with surrounding bones, and presence of anterior and middle pitlines. The suture between sphenotic and parieto-supraoccipital is a synapomorphy for catfishes. In primitive catfishes, the posterolateral corner of the cranial roof is formed by pterotic, extrascapula, and a third bone which attaches the pectoral girdle to the neurocranium; the third element may be homologous with the supracleithrum or a posttemporo-supracleithrum. The presence of a small extrascapula sutured with pterotic, pariet...

A hypothesis on the phylogenetic relationships of the neotropical catfish family Cetopsidae is proposed on the basis of the parsimony analysis of 127 morphological characters and most of the species currently recognized. The family and its two recognized subfamilies, the Cetopsinae and Helogeninae, are corroborated as monophyletic, in agreement with recent studies. Previously proposed classifications of the Cetopsinae, however, were found to be poorly representative of the phylogenetic relationships within the subfamily. Major generic rearrangements are implemented in order that the classification of the Cetopsinae reflects the phylogenetic hypothesis. Pseudocetopsis Bleeker (1862) was found to be polyphyletic and to include several disjunct lineages. One of these lineages, recently named as the genus Cetopsidium Vari, Ferraris, and de Pinna (2005), is the sister group to the rest of the Cetopsinae. Denticetopsis Ferraris (1996) is the next sister group to the remainder of the Cetopsinae. The remaining species of the Cetopsinae belong to one of two sister genera, Paracetopsis Bleeker (1862) and Cetopsis Spix and Agassiz (1829). The latter genus includes species formerly assigned to Hemicetopsis Bleeker (1862), Bathycetopsis Lundberg and Rapp Py-Daniel (1994) and Pseudocetopsis Bleeker (1862). Continued recognition of Hemicetopsis and Bathycetopsis would have required the creation of several additional new genera for various species previously in Pseudocetopsis that form a series of sister groups to a clade composed of Cetopsis oliveirai (Lundberg and Rapp Py-Daniel, 1994), C. coecutiens (Lichtenstein, 1819) and C. candiru (Spix and Agassiz, 1829). Cetopsis oliveirai is a highly paedomorphic species that displays surprising similarities with conditions in juvenile specimens of C. coecutiens, a species that attains a large body size. Such similarities are not evident in adult specimens of the latter species. A new classification is proposed, within which the subfamily Cetopsinae consists of three tribes, the Cetopsidiini, the Cetopsini and the Denticetopsini. The results of the study form the basis for a discussion of the phylogenetic position of the family within the Siluriformes, the phylogenetic biogeography of the Cetopsidae, paedomorphosis and gigantism in the family, and the effect of different semaphoronts on the intrafamilial phylogeny. Journal compilation © 2007 The Linnean Society of London, Zoological Journal of the Linnean Society, 2007, 150, 755–813. No claim to original US government works.

Nomimoscolex semenasae n. sp. is described from the primitive fish Diplomystes viedmensis (Siluriformes) from the Patagonian region of Argentina. The new species is placed in Nomimoscolex because of the cortical position of the vitelline follicles, medullary position of the testes, ovary and uterus, and having a scolex with four uniloculate suckers. N. semenasae differs from all other species in the genus by the following combination of characters: (1.apical organ absent; (2). strobila acraspedote; (3). vagina anterior or posterior to cirrus-sac and lacking a sphincter; (4). testes in one irregular layer and in two fields connected anteriorly; (5). uterine stem cortical in immature proglottides, growing from cortical stem into medullary region in mature proglottides; (6). long uteroduct; and (7). presence of spiniform microtriches on all regions of the scolex, proliferation zone and immature proglottis. This is the first record of a proteocephalidean tapeworm in D. viedmensis and in the family Diplomystidae.

Rhabdochona (Rhabdochona) acuminata is redescribed from specimens parasitizing Diplomystes mesembrinus (Siluriformes: Diplomystidae) and Percichthys trucha (Perciformes: Percichthyidae) from the Chubut River, Patagonia, Argentina. The present report is the first record of this nematode in D. mesembrinus; it also confirms P. trucha as host and Patagonia as a region of distribution for R. (R.) acuminata. Morphological features of the species were described using light and scanning electron microscopy. Compared with previous descriptions from Brazil, a very similar morphology is observed. However, a large morphometric variability is found, mainly in body size, spicule ratio, and number and arrangement of pre- and postcloacal papillae. Fil: Cremonte, Florencia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Estudios Parasitológicos y de Vectores. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Centro de Estudios Parasitológicos y de Vectores; Argentina Fil: Navone, Graciela Teresa. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Estudios Parasitológicos y de Vectores. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Centro de Estudios Parasitológicos y de Vectores; Argentina Fil: Gosztonyi, Atila Esteban. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Estudios Parasitológicos y de Vectores. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Centro de Estudios Parasitológicos y de Vectores; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico; Argentina Fil: Kuba, Luisa. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Estudios Parasitológicos y de Vectores. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Centro de Estudios Parasitológicos y de Vectores; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico; Argentina

†Hypsidoris farsonensis Lundberg and Case (1970) from the Eocene Green River Formation of Wyoming, is redescribed in detail based on much new material. The new material consists of (1) better preparations of the original type and referred specimens, and (2) many previously unreported specimens with exceptionally detailed preservation. Based on new information presented here †H. farsonensis is interpreted (A) not to belong in Ictaluridae as originally proposed, and (B) to be the sister group to all known catfish families other than Diplomystidae. Diplomystidae appears to be the sister group to †Hypsidoris plus all other known catfishes. Because of its apparent phylogenetic position (sister group to a group containing thirty nominal families), †Hypsidoris is given superfamilial (†Hypsidoroidea, new superfamily) and familial (†Hypsidoridae, new family) rank, and may be more relevant to our understanding of the early evolution of siluriform subgroups than previously thought. Catfishes (Siluriformes) ...