Multi-Segmented Arthropods from the Middle Cambrian of British Columbia (Canada)

2013 ◽  
Vol 87 (3) ◽  
pp. 493-501 ◽  
Author(s):  
David Legg
Keyword(s):  
British Columbia ◽  
National Park ◽  
Cladistic Analysis ◽  
Sister Group ◽  
Sister Group Relationship ◽  
Crown Group ◽  
Middle Cambrian ◽  
New Family ◽  
Stem Lineage ◽  
Shale Formation

A new arthropod, Kootenichela deppi n. gen. n. sp., is described from the Stanley Glacier exposure of the middle Cambrian (Series 3, Stage 5) Stephen Formation in Kootenay National Park (British Columbia, Canada). This taxon possesses a number of primitive arthropod features such as an elongate, homonomous trunk (consisting of at least 29 segments), poorly sclerotised trunk appendages, and large pedunculate eyes associated with an anterior (ocular) sclerite. The cephalon encompasses a possible antenna-like appendage and enlarged raptorial appendages with a bipartite peduncle and three spinose distal podomeres, indicative of megacheiran (“great-appendage” arthropod) affinities. The relationships of megacheirans are controversial, with them generally considered as either stem-euarthropods or a paraphyletic stem-lineage of chelicerates. An extensive cladistic analysis resolved Kootenichela as sister-taxon to the enigmatic Worthenella cambria from the middle Cambrian (Series 3, Stage 5), Burgess Shale Formation in Yoho National Park (British Columbia), which is herein reinterpreted as a megacheiran arthropod. Based on their sister-group relationship, both taxa were placed in the new family Kootenichelidae, to which Pseudoiulia from the Chengjiang biota is also tentatively assigned. All of these taxa possess an elongate, multi-segmented body and subtriangular exopods. This family occupies a basal position within a paraphyletic Megacheira, the immediate outgroup of Euarthropoda (crown-group arthropods). The resultant topology indicates that analyses that have resolved megacheirans as stem-chelicerates have done so because they have rooted on inappropriate taxa, e.g., trilobitomorphs and marrellomorphs.

Visceral anatomy of the Malaysian snake genus Xenophidion, including a cladistic analysis and allocation to a new family (Serpentes: Xenophidiidae)

1998 ◽  
Vol 19 (4) ◽  
pp. 385-405 ◽  
Author(s):  
Van Wallach ◽  
Rainer Günther
Keyword(s):  
Phylogenetic Analysis ◽  
Cladistic Analysis ◽  
Sister Group ◽  
Neotropical Region ◽  
Sister Group Relationship ◽  
Internal Anatomy ◽  
New Family ◽  
Visceral Anatomy

AbstractThe internal anatomy of Xenophidion is described and compared with that of members of other snake families. A suite of primitive characters eliminates Xenophidion as a possible member of the Caenophidia; only two characters could conceivably suggest a relationship to the Caenophidia and both are examples of losses and thus of low phylogenetic value in assessing relationships. However, among lower snakes a sister group relationship is demonstrated with the Tropidophiidae of the Neotropical region. Besides possessing nearly identical viscera and topographical arrangement thereof, Xenophidion shares several characters with the Tropidophiidae. A new family is created to contain the genus, the Xenophidiidae. The Xenophidiidae share one synapomorphy with both the Tropidophiidae and Bolyeriidae. Therefore, it is proposed that these three families be united in the superfamily Tropidophioidea. A phylogenetic analysis of 52 characters results in the following preferred hypothesis of relationships: (Boinae, (((Bolyeria, Casarea), (Xenophidion, ((Exiliboa, Ungaliophis), (Trachyboa, Tropidophis)))), Acrochordus)).

scholarly journals A Small Representative of the Phalacrocoracoidea (Cormorants and Anhingas) from the Late Oligocene of Germany

The Condor ◽  
2007 ◽  
Vol 109 (4) ◽  
pp. 929-942
Author(s):  
Gerald Mayr
Keyword(s):  
New Species ◽  
Fossil Record ◽  
Sister Group ◽  
Sister Group Relationship ◽  
Late Oligocene ◽  
Crown Group ◽  
Stem Lineage ◽  
Early Neogene ◽  
Fossil Site ◽  
A New Species

AbstractI describe a skeleton of a cormorant-like bird from Enspel, a late Oligocene (24.7 mya) fossil site in Germany, which is assigned to a new species, ?Borvocarbo stoeffelensis, sp. nov. The specimen constitutes the earliest described and most completely preserved fossil record of the Phalacrocoracoidea, the clade including Anhingidae (anhingas) and Phalacrocoracidae (cormorants). ?B. stoeffelensis shares derived features with cormorants that are absent in anhingas. Despite its cormorant-like overall morphology, an assignment to the stem lineage of Phalacrocoracidae is not straightforward, because the new species is also distinguished from crown group representatives of the clade (Anhingidae + Phalacrocoracidae) by presumably plesiomorphic features. The morphology displayed by ?B. stoeffelensis places a caveat on the assignment to the Phalacrocoracidae of other less completely known Paleogene and early Neogene taxa. Plesiomorphic features shared by ?B. stoeffelensis and extant “microcormorants” (sensu Siegel-Causey 1988) support a sister group relationship between “Microcarbo” spp. and all other extant Phalacrocoracidae.

scholarly journals Discovery of a new family of amphibians from northeast India with ancient links to Africa

2012 ◽  
Vol 279 (1737) ◽  
pp. 2396-2401 ◽  
Author(s):  
Rachunliu G. Kamei ◽  
Diego San Mauro ◽  
David J. Gower ◽  
Ines Van Bocxlaer ◽  
Emma Sherratt ◽  
...  
Keyword(s):  
Dna Sequences ◽  
Nuclear Dna ◽  
Phylogenetic Analyses ◽  
Sister Group ◽  
Northeast India ◽  
Sister Group Relationship ◽  
New Family ◽  
Ancient Lineage ◽  
Molecular Phylogenetic ◽  
Threatened Habitats

The limbless, primarily soil-dwelling and tropical caecilian amphibians (Gymnophiona) comprise the least known order of tetrapods. On the basis of unprecedented extensive fieldwork, we report the discovery of a previously overlooked, ancient lineage and radiation of caecilians from threatened habitats in the underexplored states of northeast India. Molecular phylogenetic analyses of mitogenomic and nuclear DNA sequences, and comparative cranial anatomy indicate an unexpected sister-group relationship with the exclusively African family Herpelidae. Relaxed molecular clock analyses indicate that these lineages diverged in the Early Cretaceous, about 140 Ma. The discovery adds a major branch to the amphibian tree of life and sheds light on both the evolution and biogeography of caecilians and the biotic history of northeast India—an area generally interpreted as a gateway between biodiversity hotspots rather than a distinct biogeographic unit with its own ancient endemics. Because of its distinctive morphology, inferred age and phylogenetic relationships, we recognize the newly discovered caecilian radiation as a new family of modern amphibians.

The phylogenetic position of the tuatara, Sphenodon (Sphenodontida, Amniota), as indicated by cladistic analysis of the ultrastructure of spermatozoa

1992 ◽  
Vol 335 (1274) ◽  
pp. 207-219 ◽  
Keyword(s):  
Cladistic Analysis ◽  
Sister Group ◽  
Sister Taxon ◽  
Phylogenetic Position ◽  
Sister Group Relationship ◽  
Usual Concept ◽  
Cladistic Analyses ◽  
Relationship Of

Sphenodon has traditionally been regarded as a little changed survivor of the Permo-Triassic thecodont or eosuchian ‘stem reptiles’ but has alternatively been placed in the Lepidosauria as the plesiomorphic or even apomorphic sister-taxon of the squamates. A cladistic analysis of 16 characters from spermatozoal ultrastructure of Sphenodon and other amniotes unequivocally confirms its exceedingly primitive status. The analysis suggests that monotremes are the sister-group of birds; squamates form the sister-group of a bird + monotreme clade while the three sister-groups successively below the bird + monotreme + squa- mate assemblage are the caiman, the tuatara and the outgroup (turtles). The monotreme + bird couplet, supports the concept of the Haemothermia, but can only be regarded heuristically. The usual concept of mammals as a synapsid-derived outgroup of all other extant amniotes is not substantiated spermatologically. All cladistic analyses made, and a separate consideration of apomorphies, indicate that Sphenodon is spermatologically the most primitive amniote, excepting the Chelonia. It is advanced (apomorphic) for the amniotes in only two of the 16 spermatozoal characters considered. A close, sister-group relationship of Sphenodon with squamates is not endorsed.

On a new species of Ericaella Bonaldo (Araneae, Miturgidae, Eutichurinae), with a cladistic analysis of the genus

Zootaxa ◽  
2005 ◽  
Vol 835 (1) ◽  
pp. 1
Author(s):  
ALEXANDRE B. BONALDO ◽  
ANTONIO D. BRESCOVIT ◽  
CRISTINA A. RHEIMS
Keyword(s):  
New Species ◽  
Cladistic Analysis ◽  
Sister Group ◽  
Sister Group Relationship ◽  
Outgroup Species ◽  
Optimal Tree ◽  
Fourth Species ◽  
A New Species

A fourth species of Ericaella, E. florezi n. sp., is described based on males and a female from Cauca, Colombia. A cladistic analysis of all known species of Ericaella, plus two outgroup species (Radulphius camacan Bonaldo and Eutichurus luridus Simon) is presented. The single optimal tree obtained depicted a sister group relationship between Ericaella longipes Chickering plus E. florezi sp. n. and E. samiria Bonaldo plus E. kaxinawa Bonaldo.

Phylogenies and angiosperm diversification

Paleobiology ◽  
1993 ◽  
Vol 19 (2) ◽  
pp. 141-167 ◽  
Author(s):  
James A. Doyle ◽  
Michael J. Donoghue
Keyword(s):  
Early Cretaceous ◽  
Phylogenetic Trees ◽  
Sister Group ◽  
Late Triassic ◽  
Tectonic Activity ◽  
Crown Group ◽  
Extrinsic Factors ◽  
Angiosperm Diversification ◽  
Stem Lineage ◽  
Cladistic Analyses

Approaches to patterns of diversification based on counting taxa at a given rank can be misleading, even when all taxa are monophyletic. Such “rank-based” approaches are unable to reflect a hierarchy of evolutionary events because taxa of the same rank cannot be nested within one another. Phylogenetic trees specify an order of origination of characters and clades and can therefore be used in some cases to test hypotheses on causal relationships between characters and changes in diversity. “Tree-thinking” also clarifies discussions of the age of groups, by distinguishing between splitting of the stem-lineage from its sister group and splitting of the crown-group into extant clades.Cladistic evidence that Pentoxylon, Bennettitales, and Gnetales are the sister group of angiosperms implies that the angiosperm line (angiophytes) existed by the Late Triassic. The presence of primitive members of five basic angiosperm clades indicates that the crown-group (angiosperms) had begun to diversify by the mid-Early Cretaceous (Barremian-Aptian), but not necessarily much earlier. The greatest unresolved issue raised by cladistic analyses concerns the fact that the angiosperm tree can be rooted in two almost equally parsimonious positions. Trees rooted near Magnoliales (among “woody magnoliids”) suggest that the angiosperm radiation may have been triggered by the origin of intrinsic traits, e.g., a fast-growing, rhizomatous habit in the paleoherb and eudicot subgroup. However, trees rooted among paleoherbs, which are favored by rRNA data, imply that these traits are basic for angiosperms as a whole. This could mean that the crown-group originated not long before its radiation, or, if it did originate earlier, that its radiation was delayed due to extrinsic factors. Such factors could be a trend from environmental homogeneity and stability in the Jurassic to renewed tectonic activity and disturbance in the Early Cretaceous. Potentially relevant pre-Cretaceous fossils cannot be placed with confidence, but may be located along the stem-lineage (stem angiophytes); their generally paleoherb-like features favor the paleoherb rooting. The history of angiophytes may parallel that of Gnetales: some diversification of the stem-lineage in the Late Triassic, near disappearance in the Jurassic, and vigorous radiation of the crown-group in the Early Cretaceous.

DESCRIPTION OF THE LARVAE OF ELEVEN NEARCTIC SPECIES OF HYGROTUS STEPHENS (COLEOPTERA: DYTISCIDAE: HYDROPORINAE) WITH AN ANALYSIS OF THEIR PHYLETIC RELATIONSHIPS

1990 ◽  
Vol 122 (5) ◽  
pp. 985-1035 ◽  
Author(s):  
Y. Alarie ◽  
P.P. Harper ◽  
R.E. Roughley
Keyword(s):  
Abdominal Segment ◽  
Cladistic Analysis ◽  
Sister Group ◽  
Structural Features ◽  
Sister Group Relationship ◽  
Larval Morphology ◽  
Systematic Analysis ◽  
Third Instar Larvae

AbstractA systematic analysis of larvae of 11 Nearctic species of Hygrotus Stephens was undertaken. The larvae are described and characterized; a key for their discrimination and illustrations of structural features of representatives of first- and third-instar larvae are provided. Many structural features, especially detailed variations in the chaetotaxy of cephalic capsule, head appendages, legs, last abdominal segment, and urogomphi, were found to be useful for systematic and phylogenetic comparisons. Based on 21 larval characters, a cladistic analysis of the species studied was developed. A sister-group relationship between H. laccophilinus (LeConte) and the remaining available species is suggested. The less derived species, i.e. those without natatory setae on the legs, appear phylogenetically more closely related to the larvae of Hydroporus s.str. Hygrotus masculinus (Crotch) is the most derived species of the genus and, for many characters, seems more closely related to Hyphydrini. According to larval morphology, it is hypothesized that the genus Hygrotus diverged posteriorly to the genus Hydroporus Clairville.

New information on the eggshell of ratites (Aves) and its phylogenetic implications

2003 ◽  
Vol 81 (6) ◽  
pp. 962-970 ◽  
Author(s):  
Darla K Zelenitsky ◽  
Sean P Modesto
Keyword(s):  
Cladistic Analysis ◽  
Sister Group ◽  
The Other ◽  
Data Matrix ◽  
Sister Taxon ◽  
Sister Group Relationship ◽  
New Information ◽  
Phylogenetic Implications ◽  
Skeletal Analysis ◽  
Large Living

A reappraisal of the eggshell of ratites clarifies aspects of its microstructure and ultrastructure. The phylogenetic usefulness of the eggshell data, consisting of discrete characters, is assessed using eggshell characters alone and by adding the eggshell characters to a data matrix from the literature based on skeletal characters. The resultant tree from the eggshell data alone yields Apteryx as the most basal ratite, dinornithids as the sister taxon of a clade of large living ratites, with Casuarius and Dromaius in a sister-group relationship. The combined eggshell and skeletal analysis revealed most groupings within Ratitae that were based on previous cladistic analysis of the skeletal characters alone, but also supports two equally parsimonious topologies: one identifies Dinornithidae and Apteryx as a clade at the base of Ratitae, and the other identifies Apteryx as the sister taxon of a clade consisting of all the other ratites. It is determined that the characteristics used to define the improperly named "ratite morphotype" in the current eggshell parataxonomy are not synapomorphies of the eggshell of Ratitae. An expanded cladistic analysis of the eggshells of avian and non-avian theropods is required to determine the phylogenetic usefulness of the characteristics of the ratite morphotype.

scholarly journals Cambrian bivalved arthropod reveals origin of arthrodization

2012 ◽  
Vol 279 (1748) ◽  
pp. 4699-4704 ◽  
Author(s):  
David A. Legg ◽  
Mark D. Sutton ◽  
Gregory D. Edgecombe ◽  
Jean-Bernard Caron
Keyword(s):  
Cladistic Analysis ◽  
Major Constituent ◽  
Burgess Shale ◽  
Sea Spiders ◽  
Horseshoe Crabs ◽  
Stem Lineage ◽  
Trunk Limbs ◽  
Shale Formation ◽  
Early Palaeozoic

Extant arthropods are diverse and ubiquitous, forming a major constituent of most modern ecosystems. Evidence from early Palaeozoic Konservat Lagerstätten indicates that this has been the case since the Cambrian. Despite this, the details of arthropod origins remain obscure, although most hypotheses regard the first arthropods as benthic predators or scavengers such as the fuxianhuiids or megacheirans (‘great-appendage’ arthropods). Here, we describe a new arthropod from the Tulip Beds locality of the Burgess Shale Formation (Cambrian, series 3, stage 5) that possesses a weakly sclerotized thorax with filamentous appendages, encased in a bivalved carapace, and a strongly sclerotized, elongate abdomen and telson. A cladistic analysis resolved this taxon as the basal-most member of a paraphyletic grade of nekto-benthic forms with bivalved carapaces. This grade occurs at the base of Arthropoda (panarthropods with arthropodized trunk limbs) and suggests that arthrodization (sclerotization and jointing of the exoskeleton) evolved to facilitate swimming . Predatory and fully benthic habits evolved later in the euarthropod stem-lineage and are plesiomorphically retained in pycnogonids (sea spiders) and euchelicerates (horseshoe crabs and arachnids).

scholarly journals New predatory cockroaches (Insecta: Blattaria: Manipulatoridae fam.n.) from the Upper Cretaceous Myanmar amber

2015 ◽  
Vol 66 (2) ◽  
pp. 133-138 ◽  
Author(s):  
Peter Vršanský ◽  
Günter Bechly
Keyword(s):  
Upper Cretaceous ◽  
Sister Group ◽  
Side Branch ◽  
Crown Group ◽  
New Family ◽  
Stem Group ◽  
Direct Ancestor

Abstract We describe a new extinct lineage Manipulatoridae (new family) of cockroaches from the Upper Cretaceous (Cenomanian) amber of Myanmar. Manipulator modificaputis gen. et sp. n. is a morphologically unique extinct cockroach that represents the first (of a total of 29 known worldwide) cockroach family reported exclusively from the Myanmar amber. This family represents an early side branch of the stem group of Mantodea (most probably a sister group of Eadiidae within Blattaria/Corydioidea) because it has some synapomorphies with the Mantodea (including the stem group and Eadiidae). This family also retains symplesiomorphies that exclude a position in the crown group, and furthermore has unique autapomorphies that exclude a position as a direct ancestor of Mantodea. The unique adaptations such as strongly elongated extremities and freely movable head on a long neck suggest that these animals were pursuit predators. Five additional specimens (including two immatures) reported from the Myanmar amber suggest that this group was relatively rare but belonged to the indigenous and autochthonous inhabitants of the ancient amber forest of the Myanmar region.

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