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Reassessment and Comparative Morphology of the Gonorynchiform Head Skeleton
Chapter 1 (37 pages)
By Terry Grande, Francisco José Poyato-Ariza
Abstract
The types of actinopterygian skull bones and their origins have recently been discussed in Grande and Bemis and Arratia but are worth restating. Ontogenetically, the skull is formed by the endocranium, splanchnocranium and dermatocranium. Orienting from anterior to posterior and from medial to lateral, the dorsal surface of the cranium consists of the following bones: mesethmoid, lateral ethmoids, nasals, frontals, sphenotics, pterotics, parietals, epiotics, and supraoccipita. Variation in mesethmoid size and shape is common among gonorynchiforms. The bones that constitute the cranium in ventral aspect are the mesethmoid, lateral ethmoids, vomer, parasphenoid, pterosphenoids, sphenotics, pterotics, prootics, intercalar, basioccipital, and exoccipitals. The cheek bones are the most superficial bones on the lateral surface of the osteichthyan skull. In gonorynchiforms, they are flat, often support the cephalic lateral line canals, and, as in most osteichthyans, can be ornamented.
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Morphological Analysis of the Gonorynchiform Postcranial Skeleton
Chapter 2 (33 pages)
By Terry Grande, Gloria Arratia
Abstract
The postcranial skeleton forms the framework of the body and functions in support and movement. It can be divided into two components. First, the axial skeleton lies in the longitudinal axis of the body and consists of the notochord, vertebral column, median fins, ribs and intermuscular bones. Second, the appendicular skeleton consists of the pectoral and pelvic girdles and their corresponding fins. In general, the notochord forms the hydrostatic skeleton for the developing embryo. It extends from the skull to the tip of the tail and serves as the foundation for the developing vertebral column. In gonorynchiforms, as well as in other fishes, the notochord and its obliterations set the path along where each centrum will form. Ostariophysan fishes are known for specializations of the anterior vertebral column. The most well-known specialization, diagnostic of the Otophysi, is the Weberian apparatus.
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Early Ossification and Development of the Cranium and Paired Girdles of Chanos chanos (Teleostei, Gonorynchiformes)
By Gloria Arratia, Teodora Bagarinao
Chapter 3 (34 pages)
Abstract
Numerous studies have been dedicated to larval development, growth, and larval behavior of commercially important fishes such as Chanos chanos. The specimens used in this study originated from naturally spawned eggs, hatched in October 2004 and reared in facilities of the Southeast Asian Fisheries Development Center, Aquaculture Department, Iloilo, Philippines. The water temperature ranged between 26 and 30°C. Samples were taken every day from day 1 to day 45 and then irregularly from day 46 to day 65, with size up to 80 mm standard length. The notochordal flexion in Chanos chanos begins in specimens at about 6 mm NL, but the appearance of the flexion varies from about 6 to 10 mm NL. The chondrification of elements of the caudal skeleton surrounding the caudal tip of the notochord varies intraspecifically.
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A Review of the Cranial and Pectoral Musculature of Gonorynchiform Fishes, with Comments on Their Functional Morphology and a Comparison with Other Otocephalans
By Rui Diogo
Chapter 4 (37 pages)
Abstract
Very few studies focused on the anatomy of gonorynchiforms deal in detail with their musculature. In this paper I provide an overview of the cranial musculature (excluding branchial and extrinsic eye musculature) and pectoral girdle musculature of extant gonorynchiforms. Some comments on the functional morphology of these fishes, as well as a comparison with other otocephalans, are also given. The paper is based on a review of the available literature and on the author’s own analysis of the cephalic and pectoral girdle musculature of members of the various major otocephalan groups, including representatives of the seven extant gonorynchiform genera. The overview provided here points out that there is a considerable morphological diversity of the cranial and pectoral girdle muscles within the Gonorynchiformes. Interestingly, with the exception 108of the adductor mandibulae, hyohyoideus inferioris, adductor profundus, and eventually adductor hyomandibulae and arrector dorsalis, the plesiomorphic gonorynchiform configuration for each of the muscles discussed seems to represent the plesiomorphic configuration for the Otocephala as a whole. Because of their apparent basal position within otocephalans and the rather plesiomorphic configuration of their myological structures, the gonorynchiforms can thus play an important role in studies of the comparative anatomy, functional morphology and evolution of not only otocephalans but also teleosts in general.
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The Epibranchial Organ and Its Anatomical Environment in the Gonorynchiformes, with Functional Discussions
By Françoise Pasleau, Rui Diogo, Michel Chardon
Chapter 5 (27 pages)
Abstract
All extant gonorynchiforms except for species within the genus Gonorynchus are provided with an epibranchial organ (EBO), which consists in a blind sac opening through a canal into the buccopharyngeal cavity just above and behind the last branchial slit. The proximal part of the EBO is supported by specialized elements of the last two branchial arches. The gill rakers rows of the same arches continue in the canal part of the EBO, but not in the sac. The epithelium and tunicae of the EBO are similar to those of the surrounding buccopharynx; it is plicate and rich in mucous cells. The gill rakers of all the branchial arches are particularly long and bear microbranchiospines (except in Gonorynchus and Grasseichthys). They constitute a very efficient filter complicated by bridges between the branchial arches and between the opposite gill rakers rows. All gonorynchiforms are considered to be efficient filter feeders and the EBO plays an important part in that function. A hypothesis is presented as to the water currents in the buccopharyngeal, opercular and EBO cavities, and as to the trapping of food particles by mucus and their transport into the esophagus. In 146 Gonorynchus, the EBO is functionally replaced by a dorsally elongated fifth branchial slit provided with very long gill rakers. This configuration is puzzling, regarding the phylogenetic position in which the genus has been placed in recent cladistic studies.
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The Fossil Record of Gonorynchiformes
By Emmanuel Fara, Mireille Gayet, Louis Taverne
Chapter 6 (54 pages)
Abstract
Abstract
The fossil record of gonorynchiform fishes provides key information on the diversity, palaeobiogeography, and phylogeny of the group. The first mention of fossil Gonorynchiformes dates back to Cuvier in the early 19th century, and there is still a need for a critical review of the earliest descriptions and of some key taxa today.
Fossil gonorynchiform fishes are known from the earliest Cretaceous (Berriasian-Valanginian) to the earliest Miocene, and the clade has several extant representatives. To date, the fossil record has yielded only about 18 genera and 35 species of Gonorynchiformes. With only 46 known localities, their fossil record is relatively poor compared to that of other groups of Ostariophysi. The distribution of these localities is heterogeneous in both space and time.
Debates on the phylogenetic status of Gonorynchiformes have mainly focused on the identity of the basal-most members of the clade and on its sister group. Unfortunately, very few large-scale phylogenetic studies have included the fossil representatives of the clade.
Using known fossil occurrences and several phylogenetic proposals, we conducted an exploratory diversity analysis. A traditional taxic approach shows that gonorynchiform diversity rose steadily during the Early Cretaceous and reached a peak in the Aptian-Cenomanian interval. It then declined slightly towards the end of the Cretaceous and it decreased further at the dawn of the Cenozoic. This apparent low diversity level is only interrupted by relative diversity peaks in the first half of the Eocene and in the Oligocene. In the absence of fossils after the earliest Miocene, diversity estimates are conjectural for most of the Neogene.
We found a close similarity of the estimates obtained with alternative phylogenetic hypotheses, meaning that the differences among these phylogenies have virtually no impact on inferred diversity patterns. Our diversity analysis points to some major gaps in the known fossil record, and it calls for the integration of most (if not all) fossil taxa in phylogenetic analyses.
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Gonorynchiform Interrelationships: Historic Overview, Analysis, and Revised Systematics of the Group
By Francisco José Poyato-Ariza, Terry Grande, Rui Diogo
Chapter 7 (111) pages
Abstract
The interrelationships of the gonorynchiform fishes, including fossil and Recent genera, are revised and updated. A historic summary of the different hypotheses of their phylogenetic relationships is presented. The morphological disparity of the Gonorynchiformes, as known today, prevented its two longest-known genera, Chanos and Gonorynchus, from being gathered into the same order until 1960, although their kinship had already been proposed in 1846. Discoveries of more Recent forms, and of their impressive fossil record, have added both abundant data and new challenges to the study of their phylogenetic relationships.
In addition to the historic outline, we present herein a new, entirely revised cladistic analysis of the Gonorynchiformes, including a total of 24 nominal fossil and Recent genera. Only seven of the gonorynchiform genera are living taxa, evidencing that this is a group with a diverse fossil record. The fossil record of the Gonorynchiformes, as an ensemble, is quite geographically widespread for such a small group, extending to Europe, North and South America, Africa, Australia, and Asia; it dates back to the Early Cretaceous, so that gonorynchiforms may be considered a relict or “living fossil” group.
228Previous evidence indicates that the Gonorynchiformes are sister group to the Otophysi, (i.e., fishes with a functioning Weberian apparatus), together forming the clade Ostariophysi. The results of the present analysis, consisting of 130 revised characters, including osteological and myological ones, confirm that the Gonorynchiformes comprise a monophyletic group that consists of two monophyletic, sister-group suborders, the Chanoidei and the Gonorynchoidei. The relationships of the three families {Chanidae + [Gonorynchidae + Kneriidae]} are confirmed. Each family has at least one Recent genus, and the Kneriidae have no known fossil record.
An evaluation of the evolutionary history of the Gonorynchiformes and a systematic revision are also provided in this chapter. Future research on this group should include an evaluation of some problematic taxa, mostly †Dastilbe and the Middle Eastern fossil gonorynchids. A separate approach to the interrelationships of the Chanoidei and the Gonorynchoidei, the latter including molecular studies, may help unravel further elements of phylogenetic uncertainty.
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A New Teleostean Fish from the Early Late Cretaceous (Cenomanian) of SE Morocco, with a Discussion of Its Relationships with Ostariophysans
By Frédéric Pittet, Lionel Cavin, Francisco José Poyato-Ariza
Chapter 8 (24 pages)
Abstract
†Erfoudichthys rosae gen. and sp. nov. is described on the basis of a single isolated head found in an unknown locality of the early Cenomanian Kem Kem beds, southeast of Morocco. The new species shows a combination of plesiomorphic and apomorphic characters among ostariophysans, such as a thin and elongated mesethmoid, a nasal formed by a cylindrical unit for the sensory canal extending laterally as a bony lamina, a large lacrimal, a small second infraorbital triangular in shape and wedged between the lacrimal and the third infraorbital, clusters of large conical teeth on the endopterygoids and basibranchial 2, a mandible with a ventral symphysal process and a deep coronoid process. A phylogenetic analysis of †E. rosae among Gonorynchiformes provides two very different patterns, with the new taxon located either as a stem Chanidae (= Chanoidei) or outside the Ostariophysi. This problematic phylogenetic resolution rests on the fragmentary condition of the available material and the lack of nonostariophysan teleosts for comparison, and prevents any analysis of the palaeobiogeographical signal that this taxon can provide.
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Gonorynchiformes in the Teleostean Phylogeny: Molecules and Morphology Used to Investigate Interrelationships of the Ostariophysi
By Guillaume Lecointre
Chapter 9 (45 pages)
Abstract
The phylogenetic position of the Gonorynchiformes is linked to a number of more general phylogenetic problems. From the beginning of phylogenetic systematics in ichthyology, the monophyly of ostariophysans was part of the discussion of the gonorynchiform interrelationships and must be considered first, then the position of the Ostariophysi among teleosts. Results from molecular, as well as morphological, systematics of teleosteans of the last fifteen years showed that the sister group of ostariophysans was the Clupeomorpha. It then became necessary to redefine euteleosts, which, in turn, required an assessment of the position of esocoids among teleosts. Finally, some discussions among ichthyologists about the monophyly of otophysans involved hypotheses about the position of gonorynchiformes and therefore led to a discussion of the phylogeny within ostariophysans. All these problems are reviewed by considering that a molecular phylogeny obtained through a single data set is not enough to falsify a morphological one. A clade is considered reliable when it has been corroborated through several independent sources of data. In other words, morphological synapomorphies are falsified and have to be revised only when they have been contradicted by several independent molecular phylogenies. Gonorynchiformes is the sister group of otophysans, forming the monophyletic Ostariophysi. Ostariophysans and clupeomorphs are sister groups and form the Otocephala. The sister group of the Otocephala is the Euteleostei, among which esocoids are sister group of salmonoids. Finally, something new recently appeared in that general picture. The Alepocephaloidea, which is generally considered the sister group of the Argentinoidea, could be either a member of the Otocephala or the closest sister group of it. However, those two possibilities cannot be considered reliable at present and must be taken as working hypotheses. More independent data are needed to test them.
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Systematics and Phylogenetic Relationships of Cypriniformes
By Andrew M. Simons, Nicholas J. Gidmark
Chapter 10 (32 pages)
Abstract
The Cypriniformes is a large group of fishes containing eight families, 280 genera, and over 3,500 species. These fishes are diverse, occupying a wide range of freshwater aquatic habitats in North America, Europe, Asia, India, and Africa. The taxonomy and classification of Cypriniformes is complex and phylogenetic relationships of the included groups are largely unresolved. This lack of resolution stems from the large geographic distribution of taxa, the large number of species, and the difficulty of obtaining specimens of critical taxa. In this chapter we review previous phylogenetic studies and classifications within and among cypriniform families, discuss problematic taxa, and present recent changes to the taxonomy. Recent morphological and molecular studies have provided hypotheses of relationships among included families and forced a reconsideration of the previous five-family classification. Current phylogenetic hypotheses indicate that Cypriniformes can be classified into two major monophyletic groups, Cyprinoidea, containing the Cyprinidae and Cobitoidea, containing Catostomidae, Gyrinocheilidae, Botiidae, Vailantellidae, Cobitidae, Balitoridae, and Nemacheilidae. The Cyprinidae contains a large number of species divided into several subfamilies. There 410is little agreement on the content or relationships among these taxa. Cobitoidea contains fewer species but is also the subject of taxonomic debate. Issues include the relationships of catostomids and gyrinocheilids with respect to the remaining families; species relationships within catostomids; balitorids, cobitids, and nemacheilids; and the phylogenetic position of the cobitids.
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Review of the Phylogenetic Relationships and Fossil Record of Characiformes
Chapter 11|24 pages
By Wasila M. Dahdul
Abstract
The Order Characiformes is a diverse lineage of ostariophysan fishes presently distributed in the freshwater lakes and rivers of the Neotropics and Africa. Fossil characiforms are also known from Europe. The order contains 19 families and close to 1,700 species, the majority endemic to South American drainages. Aside from a few well-supported subgroups of characiforms, relationships among families are not settled, and the taxonomy of some families, such as the complex Characidae, have undergone considerable recent revision. Most studies place the Citharinoidei (families Citharinidae + Distichodontidae) as the sister group to Characoidei, i.e., all other characiforms. Within the Characoidei, the Anostomoidea (families Anostomidae, Curimatidae, Prochilodontidae and Chilodontidae) is a well-supported lineage. The trans-Atlantic group consisting of the Neotropical families Ctenoluciidae, Erythrinidae, Lebiasinidae and African Hepsetidae is also well supported. Despite lack of resolution, three trans-Atlantic sister clades involving the African Citharinoidei, Alestidae, and Hepsetidae are consistently recovered among higher level studies, although with differing Neotropical sister groups among the published studies. Characiform fossils are known from the 442Late Cretaceous and much of the Cenozoic throughout their modern range, pointing to the deep history of the group. Controversial hypotheses on the early history of characiforms are difficult to test presently
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State of the Art of Siluriform Higher-level Phylogeny
By Rui Diogo, Zuogang Peng
Chapter 12 (51 pages)
Abstract
The Siluriformes, or catfishes, with more than 430 genera and 2750 species, represent about one third of all freshwater fishes. The relationships between the various siluriform families have long been studied. However, the number of works focused on this subject increased considerably in the past few decades because of the renewed impetus provided by the advent of cladistics in the second half of the 20th century. In this chapter, we provide an overview of those cladistic studies on the higher-level phylogeny of the Siluriformes, as a foundation for an overall discussion on the state of the art of catfish phylogeny. As will be shown, considerable progress has recently been achieved in this field, and we are arriving at some consensus concerning certain aspects of catfish higher-level phylogeny: e.g., the close relationship between ictalurids and cranoglanidids, between anchariids and ariids, and between the pimelodids, pseudopimelodids and heptapterids; the basal position within the order of the Diplomystidae, the Loricarioidei, the Cetopsidae and the Hypsidoridae; the monophyly of a clade including Heteropneustes and clariids, of a clade including auchenipterids and doradids, of a clade 466including erethistids, sisorids, akysids, amblycipitids and perhaps aspredinids; and the sister-group relationship between the clade Nematogenyidae + Trichomycteridae and the clade Callichthyidae + (Scoloplacidae + (Astroblepidae + Loricariidae)). However, despite the recent progress in catfish phylogeny, much remains to be done. For example, we are far from reaching a consensus about the relationships, and in some cases even the monophyly (e.g., Claroteidae, Bagridae, Schilbidae), of families such as the Siluridae, Austroglanididae, Schilbidae, Claroteidae, Malapteruridae, Bagridae, Mochokidae, Lacantuniidae, Chacidae, Plotosidae, and Amphiliidae.
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The Mitochondrial Phylogeny of the South American Electric Fish (Gymnotiformes) and an Alternative Hypothesis for the Otophysan Historical Biogeography
Chapter 13 (49 pages)
v
By José A. Alves-Gomes
Abstract
In order to address the mitochondrial phylogeny of the order Gymnotiformes within the Otophysi, two gonorynchiform genera were used to root the tree, and 15 genera from each remaining otophysan order (Cypriniformes, Characiformes, Siluriformes and Gymnotiformes) were sampled. The final data matrix consisted of two fragments (701 aligned nucleotides) of the 12S and 16S mitochondrial ribosomal RNA genes. Both molecules appear to be under functional/structural constraints, that can limit their efficiency as molecular marker for speciation events within a short time window. Nevertheless, 12S and 16S rRNA appear to retain enough phylogenetic information to determine branching order within the Otophysi, which is congruent with morphological data. Cypriniformes is the sister group of (Characiformes + Siluriformes + Gymnotiformes), and Characiformes is the sister group of the Siluriphysi (Siluriformes + Gymnotiformes). Adopting this hypothesis as the correct alternative, the fossil records of each order were reviewed in conjunction with their present distribution and current theories about the fragmentation of Pangea. The following scenario has been proposed: the ancestral Otophysi differentiated in freshwater habitats in Eurasia, from a lineage that invaded continental waters during the Early Cretaceous. Cypriniformes differentiated in Asia, colonized Africa but never reached South America. Cypriniform representatives arrived in North America by the Beringian land bridge and/or using a less obvious path through the Europe–Greenland–Labrador connection. The final separation of South America and Africa, between 80 and 125 million years ago, represented a vicariant event for already differentiated characiform clades, and sister-group relationships are found between African and South American genera. Characiforms reached North America only after the uplift of the Panamanian Isthmus, and not using the same route as the cypriniforms, probably for reasons associated with the current absence of characiforms in high latitudes. Siluriformes and Gymnotiformes differentiated within the isolating South America. It is proposed that catfish were able to disperse through shallow brackish/marine water by the Late Cretaceous and attained a cosmopolitan distribution by the Early Tertiary. Gymnotiforms never left South America, which may be related to functional constraints placed upon the efficiency of the Electrogenic and Electrosensory Systems (EES) by brackish (low resistivity) water.
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A Nomenclatural Analysis of Gonorynchiform Taxa
By William N. Eschmeyer, Terry Grande, Lance Grande
Chapter 14 (21 pages)
Abstract
The taxonomic history among nominal gonorynchiform taxa is complex. Until recently, most gonorynchiform taxa were aligned with nongonorynchiform groups, many of which have no close relationship to the order in its present form. Because of this complexity, researchers working on the group, especially those investigating species-level questions, have spent countless hours tracking down type specimens and trying to sort out nomenclatorial problems. The goal of this chapter, therefore, is to provide a current list of all nominal (fossil and Recent) gonorynchiform taxa along with synonomies, and the location and catalogue numbers of type material. The arrangement of taxa reflects the phylogenetic organization presented in this volume. Three families are recognized: Chanidae, Gonorynchidae and Kneriidae. The genus Phractolaemus, unlike in the more traditional classifications, is contained within the Kneriidae. Within each gonorynchiform family, all nominal genera and species are listed with synonomies.
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