Fossil species of the diatom genus Tetracyclus (Bacillariophyta, ‘ellipticus’ species group): morphology, interrelationships and the relevance of ontogeny

1996 ◽  
Vol 351 (1348) ◽  
pp. 1759-1782 ◽  
Keyword(s):  
Species Group ◽  
Life Cycles ◽  
Freshwater Species ◽  
Fossil Species ◽  
Variable Property ◽  
Elliptical Shape ◽  
Diatom Genus ◽  
Diatom Valve

The diatom genus Tetracyclus Ralfs (Bacillariophyta) is composed largely of extinct, freshwater species many of which have been used as stratigraphic markers across several continents under the assumption that they are relatively widespread and confined to precise geological epochs. Until recently the taxonomy of the genus relied almost exclusively on the shape and dimensions of the preserved siliceous valves. This study forms part of a revision of the entire genus. In this paper the morphology of fossils from the ‘ellipticus’ species group is discussed. Significant to this study is the relative usefulness of diatom valve dimensions and overall shape, seen here in the context of siliceous morphogenesis and the appearance of particular valve ‘shapes’ at particular stages in their life cycles. In addition, alternative ways of representing character data have been applied to establish whether the ‘ellipticus’ species group is monophyletic with respect to the genus. Results suggest that the ‘ellipticus’ species group is not monophyletic and that the elliptical shape of valves is better viewed as a variable property of ontogeny.

Reproduction

2017 ◽  
Author(s):  
Derek Burton ◽  
Margaret Burton
Keyword(s):  
Reproductive Behaviour ◽  
Life Cycles ◽  
Freshwater Species ◽  
Adult Fish ◽  
Reproductive Patterns ◽  
Cell Divisions ◽  
Early Stages ◽  
External Cues ◽  
Neural Factors

Interspecific fish reproductive patterns, outputs and life cycles display the greatest variability within the vertebrates. Early stages of oogenesis can be repeated in adult fish, contrasting with mammals; the pre-set sequence of cell divisions in gametogenesis is otherwise similar and is described in detail. Most fish deposit much yolk (vitellogenesis) in developing eggs. Migrations, beach-spawning and mouth-brooding are some of the interesting variations. Fertilization is predominantly external but is internal in some groups such as chondrichthyans. The omission of annual reproduction is well established in some freshwater species and the idea that this may also be the case for marine teleosts is gaining acceptance. This should be taken into account for intensively fished species. The possible roles of external cues, hormones, pheromones and neural factors acting as ‘switches’ and coordinators in gametogenesis and reproductive behaviour are discussed.

A new fossil species of the genus Limodromus Motschulsky, 1850 (Coleoptera: Carabidae: Platynini) from Baltic amber with remarks on its death process

2018 ◽  
Vol 49 (4) ◽  
pp. 399-408
Author(s):  
Sara Gamboa ◽  
Vicente M. Ortuño
Keyword(s):  
New Species ◽  
Fossil Record ◽  
Species Group ◽  
Morphological Features ◽  
Baltic Amber ◽  
Sister Taxon ◽  
Death Process ◽  
Fossil Species

Limodromus emetikos sp. n. (Coleoptera: Carabidae) is described and illustrated from Baltic amber (Eocene). Based on its morphological features, the new species is considered a sister taxon of the extant Holarctic assimilis species group. Furthermore, the specimen described here could represent a case of stress-triggered regurgitation, which would represent the first fossil record of such a process in beetles.

The Tydeoidea (Ereynetidae, Iolinidae, Triophtydeidae and Tydeidae) - An online database in the Wikispecies platform

Acarologia ◽  
2021 ◽  
Vol 61 (4) ◽  
pp. 1023-1035
Author(s):  
Henri M. André
Keyword(s):  
Tetranychus Urticae ◽  
Species Group ◽  
Type Locality ◽  
Nominal Species ◽  
Online Database ◽  
Fossil Species ◽  
Historical Aspects ◽  
Senior Synonym ◽  
Tetranychus Urticae Koch ◽  
Species Inquirendae

An online database on the taxonomy of Tydeoidea is described and is available on the Wikispecies platform at https://species.wikimedia.org/wiki/Tydeoidea. It counts 1 324 records or pages, 724 records for the Tydeidae, 334 for the Ereynetidae, 203 for the Iolinidae and 63 for the Triophtydeidae. For each taxon are detailed the parent taxa as well as the child taxa which are listed. A nec subsection lists names of child taxa that are not recommended. Subjective and objective synonymies as well as homonymies are given for each taxon. Notes provide historical aspects of past studies. The type locality and habitat of the name-bearing type and its repository are added for the nominal species-group taxa. Fossil species, species inquirendae and nomina nuda are also reported. References and external links end up a record. Tetranychus viburni Koch is resurrected from synonymy with Tetranychus urticae Koch and placed in Tydeidae; it might be a senior synonym of Tydeus goetzi Schruft. Replacement names are provided for Aureliana and Tydides (homonymy) and for Paratydaeolus clavatus (synonymy).

scholarly journals The ecomorphology of the shell of extant turtles and its applications for fossil turtles

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e10490
Author(s):  
Laura Dziomber ◽  
Walter G. Joyce ◽  
Christian Foth
Keyword(s):  
Ph Regulation ◽  
Habitat Preferences ◽  
Principal Component ◽  
3D Models ◽  
Species Group ◽  
The Body ◽  
Late Triassic ◽  
Shell Shape ◽  
Dry Land ◽  
Fossil Species

Turtles are a successful clade of reptiles that originated in the Late Triassic. The group adapted during its evolution to different types of environments, ranging from dry land to ponds, rivers, and the open ocean, and survived all Mesozoic and Cenozoic extinction events. The body of turtles is characterized by a shell, which has been hypothesized to have several biological roles, like protection, thermal and pH regulation, but also to be adapted in its shape to the ecology of the animal. However, only few studies have investigated the relationships between shell shape and ecology in a global context or clarified if shape can be used to diagnose habitat preferences in fossil representatives. Here, we assembled a three-dimensional dataset of 69 extant turtles and three fossils, in particular, the Late Triassic Proganochelys quenstedtii and Proterochersis robusta and the Late Jurassic Plesiochelys bigleri to test explicitly for a relationship between shell shape and ecology. 3D models were obtained using surface scanning and photogrammetry. The general shape of the shells was captured using geometric morphometrics. The habitat ecology of extant turtles was classified using the webbing of their forelimbs as a proxy. Principal component analysis (PCA) highlights much overlap between habitat groups. Discriminant analyses suggests significant differences between extant terrestrial turtles, extant fully aquatic (i.e., marine and riverine) turtles, and an unspecialized assemblage that includes extant turtles from all habitats, mostly freshwater aquatic forms. The paleoecology of the three fossil species cannot be determined with confidence, as all three fall within the unspecialized category, even if Plesiochelys bigleri plots closer to fully aquatic turtles, while the two Triassic species group closer to extant terrestrial forms. Although the shape of the shell of turtles indeed contains an ecological signal, it is overall too weak to uncover using shell shape in paleoecological studies, at least with the methods we selected.

scholarly journals Phylogeny, evolution, and classification of the ant genus Lasius, the tribe Lasiini, and the subfamily Formicinae (Hymenoptera: Formicidae)

2021 ◽  
Author(s):  
Brendon E Boudinot ◽  
Marek L Borowiec ◽  
Matthew M Prebus
Keyword(s):  
Molecular Phylogenetics ◽  
Phylogenetic Analyses ◽  
Social Parasitism ◽  
Molecular Data ◽  
Species Group ◽  
Total Evidence ◽  
Death Process ◽  
Ancestral State ◽  
Fossil Species

Within the Formicidae, the higher classification of nearly all subfamilies has been recently revised due to the findings of molecular phylogenetics. Here, we integrate morphology and molecular data to holistically address the evolution and classification of the ant genus Lasius, its tribe Lasiini, and their subfamily Formicinae. We accomplish this through a critical re-examination of morphology of extant and fossil taxa, molecular phylogenetic analyses, total-evidence dating under fossilized birth-death process, phylogeography, and ancestral state estimation. We use these results to provide revised taxonomic definitions for the Lasiini and select genera, and we provide a key to the genera of the Lasiini with emphasis on the Lasius genus group. We find that the crown Lasiini originated around the end of the Cretaceous on the Eurasian continent and is divisible into four morphologically distinct clades: Cladomyrma, the Lasius genus group, the Prenolepis genus group, and a previously undetected lineage we name XXXgen. n. The crown of the Lasius genus group is considerably younger than that of the Prenolepis genus group, indicating that extinction has played a major role in the evolution of the former clade. Lasius itself is divided into two well-supported monophyletic groups which are approximately equally speciose. We present evidence that temporary social parasitism and fungiculture arose in Lasius two times independently. Additionally, we recover the paraphyly of three Lasius subgenera and propose replacing all subgenera with an informal species group classification: Lasius = Acanthomyopssyn. rev., = Austrolasiussyn. n., = Cautolasiussyn. n., = Chthonolasius vsyn. n., = Dendrolasiussyn. n. Total-evidence analysis reveals that the Baltic-region amber fossil species Lasius pumilus and Pseudolasius boreus are misplaced to genus; we therefore designate XXXgen. n. for the former and XXXgen. n. for the latter. Further, we transfer XXX and Glaphyromyrmex out of the tribe, considering the former to be incertae sedis in the subfamily, and the latter a member of the Formicini (tribal transfer). Two final taxonomic actions are deemed necessary: synonymy of Lasius escamole Reza, 1925 with Liometopum apiculatum Mayr, 1870 syn. n. (subfamilial transfer), and transfer of Paratrechina kohli to Anoplolepis (tribal transfer, forming A. kohli (Forel, 1916) n. comb.).

New species and records from the Eocene of England and France support early diversification of the coral genus Acropora

2008 ◽  
Vol 82 (2) ◽  
pp. 313-328 ◽  
Author(s):  
Carden C. Wallace
Keyword(s):  
New Species ◽  
Natural History ◽  
Fossil Record ◽  
Species Group ◽  
Fossil Species ◽  
History Museum ◽  
Coral Genus ◽  
Rapid Speciation ◽  
Early Diversification ◽  
Species Groups

Five new species of the highly successful reef-building coral genus Acropora are described from Eocene locations in England and France (Acropora britannica, A. alvarezi, A. wilsonae, A. bartonensis, and A. proteacea) and additional records are given for six fossil species (A. deformis, A. anglica, A. solanderi, A. roemeri, A. lavandulina, and A. ornata), based on re-examination of material in the collections of the Natural History Museum, London. Specimens came from the Lutetian (49.0 to 41.3 Ma) of France, Bartonian (41.4 to 37.0 Ma) of England and France and Priabonian (36.0-34.2 Ma) of England. Included are the earliest record of a species with tabular or plate-like colonies similar to those in the modern “hyacinthus” species group (A. proteacea n. sp.) and the earliest records of simple hispidose forms (A. bartonensis n. sp. and A. roemeri), similar to those in the modern “florida” species group. The Priabonian material from southern England (A. brittanica n. sp. and A. anglica) shows the earliest occurrence of two sturdy species groups, the “humilis II” and “robusta” groups respectively, which now occur together on reef fronts throughout the modern Indo-Pacific. The new descriptions and records contribute to evidence that the genus diversified rapidly after its appearance in the fossil record. This diversification may have contributed to the rapid speciation and dispersal, observed in this genus during the Neogene, culminating in its extraordinary dominance of modern Indo-Pacific reefs.

The taxonomic placement of three fossil Fundulus species and the timing of divergence within the North American topminnows (Teleostei: Fundulidae)

Zootaxa ◽  
2017 ◽  
Vol 4250 (6) ◽  
pp. 577 ◽  
Author(s):  
MICHAEL J. GHEDOTTI ◽  
MATTHEW P. DAVIS
Keyword(s):  
Sequence Data ◽  
Divergence Time ◽  
Time Estimation ◽  
Species Group ◽  
Total Evidence ◽  
Morphological Data ◽  
Fossil Species ◽  
Divergence Time Estimation ◽  
Biogeographic History ◽  
Extant Species

The fossils species †Fundulus detillae, †F. lariversi, and †F. nevadensis from localities in the western United States are represented by well-preserved material with date estimations. We combined morphological data for these fossil taxa with morphological and DNA-sequence data to conduct a phylogenetic analysis and a tip-based divergence-time estimation for the family Fundulidae. The resultant phylogeny is largely concordant with the prior total-evidence phylogeny. The fossil species do not form a monophyletic group, and do not represent a discrete western radiation of Fundulus as previously proposed. The genus Fundulus diverged into subgeneric clades likely in the Eocene or Oligocene (mean age 34.6 mya, 53–23 mya), and all subgeneric and most species-group clades had evolved by the middle Miocene. †Fundulus lariversi is a member of subgenus Fundulus in which all extant species are found only in eastern North America, demonstrating that fundulids had a complicated biogeographic history. We confirmed †Fundulus detillae as a member of the subgenus Plancterus. †F. nevadensis is not classified in a subgenus but likely is related to the subgenera Plancterus and Wileyichthys. 

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