The occurrence of cartilage canals in shark vertebrae

1982 ◽  
Vol 60 (3) ◽  
pp. 483-485 ◽  
Author(s):  
John M. Hoenig ◽  
Alexander H. Walsh

Cartilage canals were found in the vertebrae of 16 species of sharks from five families. The canals variously contain blood vessels, lymph-like material, clumps of immature chondrocytes, unidentified amorphous material, or appear empty. Of 10 species examined in the family Carcharhinidae, only the dogfish, Mustelus canis, was devoid of canals. No canals were seen in the two batoid fish examined. The presence of canals may depend on the phylogenetic position or the maximum size attained by the species.

1955 ◽  
Vol 87 (9) ◽  
pp. 382-399 ◽  
Author(s):  
I. Rivard

In studies of sawflies, the family Pamphiliidae has been much neglected especially from the morphological stand point. Yuasa (1922) made a study of the larvae, but the genus Cephalcia was dealt with rather briefly. Ross (1937) and Benson (1945) made comparative morphological studies of the adults and showed the phylogenetic position of the family. More recently, Middlekauff (1953) published a description of Cephalcia marginata, a pine web-spinning sawfly which was the subject of the present study.


Zootaxa ◽  
2021 ◽  
Vol 5051 (1) ◽  
pp. 346-386
Author(s):  
SÜPHAN KARAYTUĞ ◽  
SERDAR SAK ◽  
ALP ALPER ◽  
SERDAR SÖNMEZ

An attempt was made to test if Lourinia armata (Claus, 1866)—as it is currently diagnosed—represents a species complex. Detailed examination and comparisons of several specimens collected from different localities suggest that L. armata indeed represents a complex of four closely related morphospecies that can be differentiated from one another by only detailed observations. One of the four species is identified as Lourinia aff. armata and the other three species are described as new to science and named as Lourinia wellsi sp. nov., L. gocmeni sp. nov., and L. aldabraensis sp. nov. Detailed review of previous species records indicates that the genus Lourinia Wilson, 1924 is distributed worldwide. Ceyloniella nicobarica Sewell, 1940, originally described from Nicobar Island and previously considered a junior subjective synonym of L. armata is reinstated as Lourinia nicobarica (Sewell, 1940) comb. nov. on the basis of the unique paddle-shaped caudal ramus seta V. It is postulated that almost all of these records are unreliable in terms of representing true Lourinia aff. armata described herein. On the other hand, the comparative evaluation of the illustrations and descriptions in the published literature indicates the presence of several new species waiting to be discovered in the genus Lourinia.                 It has been determined that, according to updated modern keys, the recent inclusion of the monotypic genus Archeolourinia Corgosinho & Schizas, 2013 in the Louriniidae is not justified since Archeolourinia shermani Corgosinho & Schizas, 2013 does not belong to this family but should be assigned to the Canthocamptidae. On the other hand, it has been argued that the exact phylogenetic position of the Louriniidae still remains problematic since none of the diagnostic characters supports the monophyly of the family within the Oligoarthra. It has also been argued that the close relationship between Louriniidae and Canthocamptidae is supported since both families share the homologous sexual dimorphism (apophysis) on P3 endopod. The most important characteristic that can possibly be used to define Louriniidae is the reduction of maxilliped.  


Zootaxa ◽  
2018 ◽  
Vol 4521 (4) ◽  
pp. 499
Author(s):  
SHINPEI OHASHI

Osteological and myological characters of the ophidiid Hypopleuron caninum are described here in detail. In addition to well-known characters of Ophidiidae (e.g., anal-fin origin well posterior to dorsal-fin origin; barbel-like pelvic fin; many scales), many unique or rare conditions were also recognized, including predorsal bone and maxilla condition, and canine teeth on the premaxilla, which were suggestive of a relationship with Carapidae. Furthermore, the predorsal bone appear to be homologous with the vexillar support, a carapid synapomorphy. Although several characters differ from carapid counterparts (e.g., more anterior anal-fin origin and scales absent in Carapidae), some intermediate conditions between Ophidiidae and Carapidae are apparent in Hypopleuron caninum, which may therefore occupy an intermediate phylogenetic position between the two families. A unique morphology of small second infraorbital bone is recognized in all ophidiiform species observed in this study, and it may be a synapomorphic character of the order Ophidiiformes. 


Author(s):  
Martin Stervander ◽  
William A Cresko

Abstract The fish order Syngnathiformes has been referred to as a collection of misfit fishes, comprising commercially important fish such as red mullets as well as the highly diverse seahorses, pipefishes, and seadragons—the well-known family Syngnathidae, with their unique adaptations including male pregnancy. Another ornate member of this order is the species mandarinfish. No less than two types of chromatophores have been discovered in the spectacularly colored mandarinfish: the cyanophore (producing blue color) and the dichromatic cyano-erythrophore (producing blue and red). The phylogenetic position of mandarinfish in Syngnathiformes, and their promise of additional genetic discoveries beyond the chromatophores, made mandarinfish an appealing target for whole genome sequencing. We used linked sequences to create synthetic long reads, producing a highly contiguous genome assembly for the mandarinfish. The genome assembly comprises 483 Mbp (longest scaffold 29 Mbp), has an N50 of 12 Mbp, and an L50 of 14 scaffolds. The assembly completeness is also high, with 92.6% complete, 4.4% fragmented, and 2.9% missing out of 4,584 BUSCO genes found in ray-finned fishes. Outside the family Syngnathidae, the mandarinfish represents one of the most contiguous syngnathiform genome assemblies to date. The mandarinfish genomic resource will likely serve as a high-quality outgroup to syngnathid fish, and furthermore for research on the genomic underpinnings of the evolution of novel pigmentation.


2021 ◽  
Vol 151 ◽  
Author(s):  
Dieter Weber ◽  
Fabio Stoch ◽  
Lee R.F.D. Knight ◽  
Claire Chauveau ◽  
Jean-François Flot

Microniphargus leruthi Schellenberg, 1934 (Amphipoda: Niphargidae) was first described based on samples collected in Belgium and placed in a monotypic genus within the family Niphargidae. However, some details of its morphology as well as recent phylogenetic studies suggest that Microniphargus may be more closely related to Pseudoniphargus (Amphipoda: Pseudoniphargidae) than to Niphargus. Moreover, M. leruthi ranges over 1,469 km from Ireland to Germany, which is striking since only a few niphargids have confirmed ranges in excess of 200 km. To find out the phylogenetic position of M. leruthi and check whether it may be a complex of cryptic species, we collected material from Ireland, England and Belgium then sequenced fragments of the mitochondrial cytochrome c oxidase subunit 1 gene as well as of the nuclear 28S ribosomal gene. Phylogenetic analyses of both markers confirm that Microniphargus is closer to Pseudoniphargus than to Niphargus, leading us to reallocate Microniphargus to Pseudoniphargidae. We also identify three congruent mito-nuclear lineages present respectively in Ireland, in both Belgium and England, and in England only (with the latter found in sympatry at one location), suggesting that M. leruthi is a complex of at least three species with a putative centre of origin in England.


PLoS ONE ◽  
2021 ◽  
Vol 16 (6) ◽  
pp. e0251900
Author(s):  
Alejandro Blanco

Our current knowledge on the crocodyliform evolution is strongly biased towards the skull morphology, and the postcranial skeleton is usually neglected in many taxonomic descriptions. However, it is logical to expect that it can contribute with its own phylogenetic signal. In this paper, the changes in the tree topology caused by the addition of the postcranial information are analysed for the family Allodaposuchidae, the most representative eusuchians in the latest Cretaceous of Europe. At present, different phylogenetic hypotheses have been proposed for this group without reaching a consensus. The results of this paper evidence a shift in the phylogenetic position when the postcranium is included in the dataset, pointing to a relevant phylogenetic signal in the postcranial elements. Finally, the phylogenetic relationships of allodaposuchids within Eusuchia are reassessed; and the internal relationships within Allodaposuchidae are also reconsidered after an exhaustive revision of the morphological data. New and improved diagnoses for each species are here provided.


PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e12597
Author(s):  
Alice M. Clement ◽  
Richard Cloutier ◽  
Jing Lu ◽  
Egon Perilli ◽  
Anton Maksimenko ◽  
...  

Background The megalichthyids are one of several clades of extinct tetrapodomorph fish that lived throughout the Devonian–Permian periods. They are advanced “osteolepidid-grade” fishes that lived in freshwater swamp and lake environments, with some taxa growing to very large sizes. They bear cosmine-covered bones and a large premaxillary tusk that lies lingually to a row of small teeth. Diagnosis of the family remains controversial with various authors revising it several times in recent works. There are fewer than 10 genera known globally, and only one member definitively identified from Gondwana. Cladarosymblema narrienense Fox et al. 1995 was described from the Lower Carboniferous Raymond Formation in Queensland, Australia, on the basis of several well-preserved specimens. Despite this detailed work, several aspects of its anatomy remain undescribed. Methods Two especially well-preserved 3D fossils of Cladarosymblema narrienense, including the holotype specimen, are scanned using synchrotron or micro-computed tomography (µCT), and 3D modelled using specialist segmentation and visualisation software. New anatomical detail, in particular internal anatomy, is revealed for the first time in this taxon. A novel phylogenetic matrix, adapted from other recent work on tetrapodomorphs, is used to clarify the interrelationships of the megalichthyids and confirm the phylogenetic position of C. narrienense. Results Never before seen morphological details of the palate, hyoid arch, basibranchial skeleton, pectoral girdle and axial skeleton are revealed and described. Several additional features are confirmed or updated from the original description. Moreover, the first full, virtual cranial endocast of any tetrapodomorph fish is presented and described, giving insight into the early neural adaptations in this group. Phylogenetic analysis confirms the monophyly of the Megalichthyidae with seven genera included (Askerichthys, Cladarosymblema, Ectosteorhachis, Mahalalepis, Megalichthys, Palatinichthys, and Sengoerichthys). The position of the megalichthyids as sister group to canowindrids, crownward of “osteolepidids” (e.g.,Osteolepis and Gogonasus), but below “tristichopterids” such as Eusthenopteron is confirmed, but our findings suggest further work is required to resolve megalichthyid interrelationships.


Author(s):  
Cathrin Spröer ◽  
Ulrike Mendrock ◽  
Jolantha Swiderski ◽  
Elke Lang ◽  
Erko Stackebrandt

1990 ◽  
Vol 38 (5) ◽  
pp. 519 ◽  
Author(s):  
PR Baverstock ◽  
M Krieg ◽  
J Birrell ◽  
GM Mckay

Microcomplement fixation of albumin was used to examine the phylogenetic relationships among the ringtail possums, family Pseudocheiridae. Phylogenetic analysis of the data supports the hypothesis of at least three distinct clades within the family: one containing Petauroides and Hemibelideus; a second consisting of Pseudocheirus herbertensis, Ps. forbesi, Ps. mayeri, and Ps. canescens; and a third containing Ps. archeri, Ps. corinnae, Ps. cupreus and Ps. dahli. The data have not resolved the phylogenetic position of Ps. peregrinus, which may either form a separate clade or lie close to the Ps. archeri clade.


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