scholarly journals The atlas-axis complex of the Late Paleozoic Diadectomorpha and basal amniotes: defining the primitive condition of the atlas-axis complex of amniotes

1992 ◽  
Vol 6 ◽  
pp. 283-283
Author(s):  
Stuart S. Sumida ◽  
R. Eric. Lombard ◽  
David S Berman
Keyword(s):  
Phylogenetic Analyses ◽  
Dorsal Surface ◽  
Sister Group ◽  
Ventral Surface ◽  
Late Paleozoic ◽  
Neural Spine ◽  
Neural Arch ◽  
Primitive Condition ◽  
Paleozoic Tetrapods

During the past decade, phylogenetic analyses of Late Paleozoic tetrapods have consistently demonstrated that the Permo-Pennsylvanian tetrapod suborder Diadectomorpha is closely related to more traditionally defined amniotes. Recent analyses provide two competing hypotheses of relationship: 1) the Diadectomoropha is the sister group of all amniotes, or 2) the Diadectomorpha and Synapsida comprise the most primitive clade within the Amniota. Subsequently more derived groups within the Amniota are: the reptilian family Captorhinidae, and the Protorothyrididae plus the Diapsida. The availability of well preserved atlas-axis complexes for all of the better known genera of diadectomorphs now allow a determination of the primitive condition of the atlas-axis complex for the Amniota. Further, accepted hypotheses of phylogenetic relationships among Late Paleozoic tetrapods allow mapping of features of the atlas-axis complex onto predefined topologies so that the transformations of the complex may be analyzed.The diadectomorph atlas-axis complex may be characterized in the following manner: paired, well developed proatlases and atlantal neural arches; lack of proatlantal and atlantal neural spines with only posteriorly directed epipophyses present; an extremely robust atlantal intercentrum; tight articulation of the atlantal pleurocentrum with the dorsal aspect of the axial intercentrum preventing exposure of the former on the ventral surface of the vertebral column; a large, anteriorly directed midline projection of the axial intercentrum; a tall and well-developed axial neural spine, presumably for attachment of strong occipital muscles and ligaments. Except for the anterior projection of the axial intercentrum (which is an autapomorphic feature of diadectomorphs), basal amniotes share all of these features with diadectomorphs. Shared, derived features of the atlas-axis complex of diadectomorphs plus other basal amniotes include: 1) fusion of the axial centrum and neural arch, 2) small epipophyses of the atlantal neural arch and, with the exception of Tseajaia, 3) fusion of the atlantal pleurocentrum to the dorsal surface of the axial intercentrum.The morphology of the atlas-axis complex alone is not sufficient to generate hypotheses of relationship between diadectomorphs and other basal amniotes. However, the atlas-axis complexes of diadectomorphs and other basal amniotes are clearly more similar to one-another than to those of other taxa.

Morphology of the atlas-axis complex of the late Palaeozoic tetrapod suborders Diadectomorpha and Seymouriamorpha

1992 ◽  
Vol 336 (1277) ◽  
pp. 259-273 ◽  
Keyword(s):  
Posterior Margin ◽  
Dorsal Surface ◽  
Neural Spine ◽  
Neural Arch ◽  
Total Height ◽  
Late Palaeozoic

The atlas-axis complexes of the better-known genera of the Permo-Pennsylvanian tetrapod suborder Diadectomorpha are described and compared with those of other late Palaeozoic tetrapods. One new synapomorphy of the Diadectomorpha is identified: a large, anteriorly directed, midventral, projection of the axial intercentrum that articulates with a midventral furrow on the posterior margin of the atlantalintercentrum . Within the Diadectomorpha diadectids are apomorphic in possessing a large, anteriorly tapering axial neural spine, that accounts for approximately 40% of the total height of the axis; Limnoscelis is apomorphic in having divided parapophyseal facets of the atlantal intercentrum and anteriorly directed ventral processes of the atlantal intercentrum . Relative to the atlas-axis complex in the more primitive amphibian suborder Seymouriamorpha, that of diadectomorphs and other basal amniotes share two derived features: the atlantal pleurocentrum is fused to the dorsal surface of the axial intercentrum , except in Tseajaia where the elements are not fused but are positioned similarly; and the axial pleurocentrum and neural arch are fused in all observable stages of ontogeny. Reinterpretation of the atlantal neural arch in Seymouria indicates that it does not possess neural spines, a feature it shares with the Diadectomorpha and basal amniotes.

A new species of Limnonectes (Amphibia: Anura: Dicroglossidae) from Vietnam

Zootaxa ◽  
2020 ◽  
Vol 4894 (3) ◽  
pp. 387-402
Author(s):  
CUONG THE PHAM ◽  
DANG TRONG DO ◽  
MINH DUC LE ◽  
HANH THI NGO ◽  
LUAN THANH NGUYEN ◽  
...  
Keyword(s):  
New Species ◽  
Phylogenetic Analyses ◽  
Dorsal Surface ◽  
Ventral Surface ◽  
Diagnostic Characters ◽  
South Central ◽  
Central Vietnam ◽  
Medial Edge ◽  
A New Species

A new species of Limnonectes from Phu Yen Province, South-central Vietnam is described based on morphological and molecular differences. Morphologically, the new species is distinguishable from its congeners on the basis of a combination of the following diagnostic characters: SVL 49.8–77.9 mm in males, 40.8–61.8 mm in females; males with moderately enlarged head (HL/SVL 0.47, HW/SVL 0.48); head slightly broader than long (HL/HW 0.97 in males, 0.95 in females); vomerine teeth present; external vocal sacs absent; rostral length short (RL/SVL 0.15); tympanum invisible; dorsal surface of head, body and flanks with ridges and tubercles; dorsal surface of tibia and foot distinctly tuberculate, covered with moderately dense, small, low tubercles; supratympanic fold present; dorsolateral fold absent; Finger I with nuptial pad, composed of minute spines on dorsal surface and medial edge in males; toes webbed to distal of terminal phalanx, webbing formula I0–0II0–0III0–0IV0-–0V0; in life, dorsum yellowish brown with dark brown markings; ventral surface white with brown markings. In phylogenetic analyses, the new species from Vietnam and Limnonectes fastigatus as well as L. kiziriani form a clade, which is sister to L. fragilis from China, although the nodal support values for the set of relationships are insignificant from all analyses. 

The atlas-axis complex in the late Paleozoic genus Diadectes and the characteristics of the atlas-axis complex across the amphibian to amniote transition

1991 ◽  
Vol 65 (6) ◽  
pp. 973-983 ◽  
Author(s):  
Stuart S. Sumida ◽  
R. Eric Lombard
Keyword(s):  
Late Paleozoic ◽  
Neural Spine ◽  
Early Permian ◽  
Neural Arch ◽  
Exposure Fusion

The atlas-axis complex in the Early Permian diadectomorph Diadectes is shown to be similar to those of a variety of primitive amniotes. Diadectes does not possess elements in addition to the standard complement seen in advanced batrachosaurs and primitive amniotes as previously thought. Characteristics of the complex include: paired, well-developed proatlases and atlantal neural arches, lack of atlantal neural spines, an extremely robust atlantal intercentrum, fusion of the atlantal pleurocentrum and axial intercentrum, a large anterior projection of the axial intercentrum, exclusion of the atlantal pleurocentrum from ventral exposure, fusion of axial neural arch and pleurocentrum, and a robustly developed axial neural spine. An analysis of the transformations of the atlas-axis complex in advanced anthracosaurs and primitive amniotes indicates that many of the characteristics of the complex previously thought to be definitive of amniotes or reptiles appear to be conditions common to Diadectes plus Amniota.

A new species of Limnonectes (Amphibia: Anura: Dicroglossidae) from Vietnam

Zootaxa ◽  
2017 ◽  
Vol 4269 (4) ◽  
pp. 545
Author(s):  
CUONG THE PHAM ◽  
MINH DUC LE ◽  
TAO THIEN NGUYEN ◽  
THOMAS ZIEGLER ◽  
ZHENG JUN WU ◽  
...  
Keyword(s):  
New Species ◽  
Phylogenetic Analyses ◽  
Dorsal Surface ◽  
Ventral Surface ◽  
Sister Taxon ◽  
Diagnostic Characters ◽  
Large Size ◽  
Hind Limbs ◽  
Statistical Support ◽  
A New Species

A new species of Limnonectes is described from northeastern Vietnam based on morphological and molecular differences. Morphologically, the new species is distinguishable from its congeners on the basis of a combination of the following diagnostic characters: Large size (SVL 50.1–68.9 in males, 45.5–63.0 mm in females); males with moderately enlarged head (HL/SVL 0.48), head longer than wide; vomerine teeth present; external vocal sacs absent; rostral length short (RL/SVL 0.16 in males, 0.15 in females); tympanum distinct (TD/ED 0.63 in males, 0.60 in females); dorsal surface of head, body and flanks with flattened tubercles; dorsal surface of tibia possessing small tubercles; supratympanic fold present; dorsolateral fold absent; webbing formula I0–0II0–1/3III0–1/3IV1/2–0V; in life, dorsum yellowish brown with a dark brown marking; throat and chest white with dark brown marking; ventral surface of fore and hind limbs as well as belly white. In phylogenetic analyses, the new species is placed as the sister taxon to Limnonectes fujianensis with strong statistical support in all analyses.

scholarly journals A New Species of the Genus Zhangixalus (Amphibia: Rhacophoridae) from Vietnam

2020 ◽  
Author(s):  
Hoa Thi NINH ◽  
Tao Thien NGUYEN ◽  
Nikolai ORLOV ◽  
Truong Quang NGUYEN ◽  
Thomas ZIEGLER
Keyword(s):  
New Species ◽  
Phylogenetic Analyses ◽  
Dorsal Surface ◽  
Ventral Surface ◽  
Morphological Characters ◽  
Molecular Data ◽  
Species Number ◽  
White Stripe ◽  
Hind Limbs ◽  
A New Species

We describe a new species of the genus Zhangixalus Li, Jiang, Ren & Jiang, 2019 from Ha Giang Province, Vietnam based on morphological and molecular data. In the molecular phylogenetic analyses, the new species is nested in the Zhangixalus duboisi (Ohler, Marquis, Swan & Grosjean, 2000) group, where it is sister to Z. duboisi with a genetic distance of 2.51%. The new species, Zhangixalus franki sp. nov., differs from its congeners by a combination of the following morphological characters: size large, SVL 77.9–85.8 mm in males; finger webbing formula I1-1II0-1III½-0IV; dorsal surface of head and body green with dark brown spots; ventral surface grey or dark grey, white stripe along edge of jaw, insertion of limbs, and along lateral ridges of fore and hind limbs and flank, separating upper green part from lower grey part. The new species occurs in evergreen montane tropical forests at an elevation of ca 1300 m a.s.l. The new discovery brings the total number of known species in the genus Zhangixalus to 38 and the species number reported from Vietnam to nine.

scholarly journals A species of the genus Panophrys (Anura, Megophryidae) from southeastern Guizhou Province, China

ZooKeys ◽  
2021 ◽  
Vol 1047 ◽  
pp. 27-60
Author(s):  
Tao Luo ◽  
Yali Wang ◽  
Siwei Wang ◽  
Xueli Lu ◽  
Weifeng Wang ◽  
...  
Keyword(s):  
New Species ◽  
16S Rrna ◽  
Phylogenetic Analyses ◽  
Morphological Characteristics ◽  
Dorsal Surface ◽  
Ventral Surface ◽  
Genetic Distances ◽  
The Body ◽  
Guizhou Province ◽  
Upper Eyelid

Herein, we describe Panophrys congjiangensissp. nov. obtained from the Yueliangshan Nature Reserve, Congjiang County, Guizhou Province, China. Phylogenetic analyses based on the mitochondrial genes 16S rRNA and COI indicated that this new species represented an independent lineage, closely related to P. leishanensis. The uncorrected genetic distances between the new species and its closest congener, P. leishanensis, were 3.0% for 16S rRNA and 8.4% for COI. The new species is distinguished from its congeners by a combination of the following morphological characteristics (1) medium body size (SVL 28.6–33.4 mm in males and 38.4–40.2 mm in females); (2) a small horn-like tubercle at the edge of each upper eyelid; (3) the tympanum distinctly visible (TD/ED ratio 0.47–0.66); (4) vomerine teeth absent; (5) the tongue not notched behind; (6) a narrow and unobvious lateral fringe on toes; (7) relative finger lengths II < I < V < III; (8) rudimentary webs on toes; (9) hindlimbs slender, heels overlapping when thighs are positioned at right angles to the body; (10) two metacarpal tubercles on the palm, with the inner metatarsal tubercle long and oval-shaped; (11) the tibiotarsal articulation reaching the nostril when the leg is adpressed and stretched forward; (12) dorsal skin rough with numerous orange–red granules, ventral surface smooth; (13) a single internal subgular vocal sac present in males; and (14) in breeding males, weak gray-black nuptial pads with black nuptial spines present on the dorsal surface of the bases of the first and second fingers. To date, the new species is only known from the type locality.

A new species of Limnonectes (Amphibia: Anura: Dicroglossidae) from Vietnam

Zootaxa ◽  
2018 ◽  
Vol 4508 (1) ◽  
pp. 115 ◽  
Author(s):  
CUONG THE PHAM ◽  
MINH DUC LE ◽  
HANH THI NGO ◽  
THOMAS ZIEGLER ◽  
TRUONG QUANG NGUYEN
Keyword(s):  
New Species ◽  
Phylogenetic Analyses ◽  
Dorsal Surface ◽  
Ventral Surface ◽  
Sister Taxon ◽  
Undescribed Species ◽  
Diagnostic Characters ◽  
Central Vietnam ◽  
A New Species

A new species of Limnonectes from central Vietnam is described based on morphological and molecular differences. Morphologically, the new species is distinguishable from its congeners on the basis of a combination of the following diagnostic characters: SVL 47.5–60.9 in males, 42.3–51.1 mm in females; males with moderately enlarged head (HL/SVL 0.48), head longer than wide; vomerine teeth present; external vocal sacs absent; rostral length short (RL/SVL 0.14 in males, 0.15 in females); tympanum invisible; dorsal surface of head, body, and flanks smooth; dorsal surface of tibia and foot distinctly tuberculate, covered with moderately dense, small, low tubercles; supratympanic fold present; dorsolateral fold absent; toes webbed to posterior of terminal phalanx; in life, dorsum with light yellowish brown markings, throat and chest white with brown markings, and ventral surface of abdomen white or white with brown markings. In phylogenetic analyses, the new species is the sister taxon to an undescribed species from Cambodia. 

scholarly journals Notes on the axial skeleton of the titanosaur Bonitasaura salgadoi (Dinosauria-Sauropoda)

2011 ◽  
Vol 83 (1) ◽  
pp. 235-246 ◽  
Author(s):  
Pablo A. Gallina
Keyword(s):  
Relative Position ◽  
Phylogenetic Analyses ◽  
Spatial Arrangement ◽  
Axial Skeleton ◽  
Neural Spine ◽  
Lateral Expansion ◽  
Dorsal Region ◽  
Spine Morphology ◽  
Posterior Elements

Sauropod axial anatomy is particularly important in understanding morphological features and phylogenetic analyses. Spatial arrangement of zygapophyses and rib articulations, as well as their complex laminar development, help to recognize the relative position of isolated vertebral elements. The presence of anterior, mid and posterior elements along the cervical, dorsal and caudal series in Bonitasaura salgadoi allows the analysis of several anatomical characteristics. These include the pattern of neurocentral closure with unfused, partially fused and completely fused elements in a peculiar temporal sequence, as well as several neural spine modifications and the laminar arrangement. The variations in neural spine morphology include a lateral expansion of the distal tip in cervico-dorsal region, different lateral constituents of these lateral expansions, and a marked deviation in spine angulation. The spinal inclination allows the division into three easily recognizable vertebral regions separated by two landmarks, which adds support in the determination of an accurate vertebral position for isolated elements. Finally, an analysis of the vertebral laminae reveals the importance of examining vertebral series in order to recognize laminar homologies and developmental series. Two vertebral laminae are analyzed here.

Scanning electron microscopy of the integument of schistosoma rodhaini

1986 ◽  
Vol 44 ◽  
pp. 132-133
Author(s):  
P. Evers ◽  
C. Schutte ◽  
C. D. Dettman
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Oral Sucker ◽  
Adult Male ◽  
Dorsal Surface ◽  
Ventral Surface ◽  
Sensory Receptors ◽  
East African ◽  
Dorsal Midline ◽  
Scanning Electron

S.rodhaini (Brumpt 1931) is a parasite of East African rodents which may possibly hybridize with the human schistosome S. mansoni. The adult male at maturity measures approximately 3mm long and possesses both oral and ventral suckers and a marked gynaecophoric canal. The oral sucker is surrounded by a ring of sensory receptors with a large number of inwardly-pointing spines set into deep sockets occupying the bulk of the ventral surface of the sucker. Numbers of scattered sensory receptors are found on both dorsal and ventral surfaces of the head (Fig. 1) together with two conspicuous rows of receptors situated symmetrically on each side of the midline. One row extends along the dorsal surface of the head midway between the dorsal midline and the lateral margin.

Diversification of the North American Doellingeria-Eucephalus Clade (Astereae: Asteraceae) Inferred from Molecular and Morphological Evidence

2019 ◽  
Vol 44 (4) ◽  
pp. 930-942
Author(s):  
Geraldine A. Allen ◽  
Luc Brouillet ◽  
John C. Semple ◽  
Heidi J. Guest ◽  
Robert Underhill
Keyword(s):  
North American ◽  
Sequence Data ◽  
Phylogenetic Analyses ◽  
Sister Group ◽  
Morphological Evidence ◽  
South American ◽  
New Combinations ◽  
The North ◽  
Hybridization Event ◽  
Ancient Hybridization

Abstract—Doellingeria and Eucephalus form the earliest-diverging clade of the North American Astereae lineage. Phylogenetic analyses of both nuclear and plastid sequence data show that the Doellingeria-Eucephalus clade consists of two main subclades that differ from current circumscriptions of the two genera. Doellingeria is the sister group to E. elegans, and the Doellingeria + E. elegans subclade in turn is sister to the subclade containing all remaining species of Eucephalus. In the plastid phylogeny, the two subclades are deeply divergent, a pattern that is consistent with an ancient hybridization event involving ancestral species of the Doellingeria-Eucephalus clade and an ancestral taxon of a related North American or South American group. Divergence of the two Doellingeria-Eucephalus subclades may have occurred in association with northward migration from South American ancestors. We combine these two genera under the older of the two names, Doellingeria, and propose 12 new combinations (10 species and two varieties) for all species of Eucephalus.

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