scholarly journals New austrolimulid from Russia supports role of Early Triassic horseshoe crabs as opportunistic taxa

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e11709
Author(s):  
Russell D.C. Bicknell ◽  
Dmitry E. Shcherbakov
Keyword(s):  
Horseshoe Crab ◽  
New Taxon ◽  
Geometric Morphometric ◽  
The Family ◽  
Horseshoe Crabs ◽  
New Material ◽  
Permian Extinction ◽  
Geometric Morphometric Analysis ◽  
Taxonomic Examination

Horseshoe crabs are extant marine euchelicerates that have a fossil record extending well into the Palaeozoic. Extreme xiphosurid morphologies arose during this evolutionary history. These forms often reflected the occupation of freshwater or marginal conditions. This is particularly the case for Austrolimulidae—a xiphosurid family that has recently been subject to thorough taxonomic examination. Expanding the austrolimulid record, we present new material from the Olenekian-aged Petropavlovka Formation in European Russia and assign this material to Attenborolimulus superspinosus gen. et sp. nov. A geometric morphometric analysis of 23 horseshoe crab genera illustrates that the new taxon is distinct from limulid and paleolimulid morphologies, supporting the assignment within Austrolimulidae. In considering Triassic austrolimulids, we suggest that the hypertrophy or reduction in exoskeletal sections illustrate how species within the family evolved as opportunistic taxa after the end-Permian extinction.

scholarly journals Xiphosurid from the Tournaisian (Carboniferous) of Scotland confirms deep origin of Limuloidea

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Russell D. C. Bicknell ◽  
Stephen Pates
Keyword(s):  
Fossil Record ◽  
Evolutionary History ◽  
Horseshoe Crab ◽  
New Taxon ◽  
Geometric Morphometric ◽  
Lower Carboniferous ◽  
Morphometric Analyses ◽  
Lower Ordovician ◽  
Horseshoe Crabs ◽  
History Of

AbstractHorseshoe crabs are archetypal marine chelicerates with a fossil record extending from the Lower Ordovician to today. The major horseshoe crab groups are thought to have arisen in the middle to late Palaeozoic. Here we present the oldest known limuloid from the lower Carboniferous (Tournaisian stage, c. 350 million years ago) of Scotland: Albalimulus bottoni gen. et sp. nov. A comprehensive phylogenetic analysis supports the placement of A. bottoni as a representative of the extant family Limulidae and 100 million years older than any other limulid taxon. The use of geometric morphometric analyses corroborate the erection of the new taxon and illustrates the exploitation of morphospace by xiphosurids. This new taxon highlights the complex evolutionary history of xiphosurids and the importance of documenting these unique Palaeozoic individuals.

A new limulid genus from the Strelovec Formation (Middle Triassic, Anisian) of northern Slovenia

2019 ◽  
Vol 156 (12) ◽  
pp. 2017-2030 ◽  
Author(s):  
Russell D. C. Bicknell ◽  
Jure Žalohar ◽  
Primož Miklavc ◽  
Bogomir Celarc ◽  
Matija Križnar ◽  
...  
Keyword(s):  
Middle Triassic ◽  
Ecological Niches ◽  
New Taxon ◽  
New Genus And Species ◽  
Quantitative Evidence ◽  
The Family ◽  
Low Diversity ◽  
Horseshoe Crabs ◽  
Permian Extinction ◽  
Systematic Palaeontology

AbstractHorseshoe crabs are an archetypal chelicerate group with a fossil record extending back to Early Ordovician time. Although extensively studied, the group generally has a low diversity across the Phanerozoic Eonothem. Here, we expand the known diversity of true horseshoe crabs (Xiphosurida) by the description of a new taxon from the Middle Triassic Strelovec Formation of the Slovenian Alps. The mostly complete fossil is preserved as an external mould and assigned to the family Limulidae Zittel, 1881 as Sloveniolimulus rudkini, n. gen., n. sp. The use of landmark and semilandmark geometric morphometrics is explored to corroborate the systematic palaeontology and suggests that the new genus and species are valid. We also provide the first quantitative evidence for the extensive diversity of Triassic horseshoe crabs. We suggest that Triassic horseshoe crabs likely filled many ecological niches left vacant after the end-Permian extinction.

Visual performance of horseshoe crabs day and night

1991 ◽  
Vol 7 (3) ◽  
pp. 179-189 ◽  
Author(s):  
Maureen K. Powers ◽  
Robert B. Barlow ◽  
Leonard Kass
Keyword(s):  
Horseshoe Crab ◽  
Average Distance ◽  
Natural Behavior ◽  
Object A ◽  
Circadian Changes ◽  
Horseshoe Crabs ◽  
Normal Environment ◽  
And Function ◽  
Daily Changes

AbstractA circadian clock modulates the structure and function of the lateral eyes of Limulus polyphemus, greatly increasing their sensitivity at night. During the mating season, male Limulus are visually attracted both day and night to females and objects that resemble females. This paper asks how well Limulus can see day and night, and whether the circadian changes in retinal sensitivity might influence the ability of these animals to find mates. We recorded the visual behavior of male and female horseshoe crabs in the vicinity of an object – a cement hemisphere (29.5 cm diameter) similar in size and shape to a female horseshoe crab – placed in a mating area near Mashnee Dike, Bourne, Massachusetts. Males oriented toward this target from an average distance of 0.94 m during the day and 0.88 m at night; and females appeared to avoid the target. We conclude that males can see potential mates at night almost as well as they can during the day. Apparently the circadian changes in the retina help compensate for the daily changes in illumination in the animal's normal environment. This study provides the first evidence for a role of visual circadian rhythms in an animal's natural behavior.

scholarly journals A new species of Prosyntexis Sharkey, 1990 (Hymenoptera: Sepulcidae) from the Lower Cretaceous Crato Formation of Brazil confirmed by geometric morphometric analysis

2021 ◽  
Vol 4 (2) ◽  
pp. 171-177
Author(s):  
CORENTIN JOUAULT ◽  
ANDRÉ NEL
Keyword(s):  
New Species ◽  
Morphometric Analysis ◽  
Lower Cretaceous ◽  
The Other ◽  
New Taxon ◽  
Additional Specimen ◽  
Geometric Morphometric ◽  
Geometric Morphometric Analysis ◽  
A New Species

Examination of new fossil specimens of Prosyntexis from the Lower Cretaceous Crato Formation of Brazil reveled a new species namely Prosyntexis sennlaubi sp. nov. To ensure the validity of the new taxon we examined previously described and figured specimens but we also figured an additional specimen of Prosyntexis gouleti Sharkey, 1990. The new species can be differentiated from the other Prosyntexis species of the Crato formation by its larger size but also in having the cell 2R1 small, the cell 2M small and short, the cell 3R1 narrow and the vein a directed toward wing apex. We performed a Geometric Morphometric Analysis (GMA) to estimate the variation in the forewing venation of the two species from the Crato Formation and ensure our placement.

scholarly journals New insights into the earlier evolutionary history of epiphytic macrolichens

2021 ◽  
Author(s):  
Qiuxia Yang ◽  
Yanyan Wang ◽  
Robert Lucking ◽  
H. Thorsten Lumbsch ◽  
Xin Wang ◽  
...  
Keyword(s):  
Morphometric Analysis ◽  
Evolutionary History ◽  
Terrestrial Ecosystems ◽  
Molecular Dating ◽  
Geometric Morphometric ◽  
New Family ◽  
Family Level ◽  
History Of ◽  
New Material ◽  
Geometric Morphometric Analysis

Lichens are well known as pioneer organisms colonizing bare surfaces such as rocks and therefore have been hypothesized to play a role in the early formation of terrestrial ecosystems. Given the rarity of fossil evidence, our understanding of the evolutionary history of lichen-forming fungi is primarily based on molecular dating approaches. These studies suggest extant clades of macrolichens diversified after the K-Pg boundary. Here we corroborate the mid-Mesozoic fossil Daohugouthallus ciliiferus as an epiphytic macrolichen that predates the K-Pg boundary by 100 Mys. Based on new material and geometric morphometric analysis, we demonstrate that the Jurassic fossil is morphologically most similar to Parmeliaceae, but cannot be placed in Parmeliaceae or other similar family-level clades forming macrolichens as these evolved much later. Consequently, a new family, Daohugouthallaceae, is proposed here to accommodate this fossil, which reveals macrolichens may have been diverse long before the Cenozoic diversification of extant lineages.

scholarly journals Democracy, Human Rights, and Islamic Family Law in Post-Soeharto Indonesia

2015 ◽  
Vol 5 ◽  
Author(s):  
Mark Cammack ◽  
Adriaan Bedner ◽  
Stijn Van Huis
Keyword(s):  
Family Law ◽  
Law Reform ◽  
Constitutional Court ◽  
State Control ◽  
Reform Initiatives ◽  
The Family ◽  
New Material ◽  
Divorce Rates ◽  
Islamic Family Law

This article examines the developments in Indonesian family law in the aftermath of the political transition that occurred in 1998. Its focus is on the position of the Islamic courts and the role of the women’s movement as a driver of reform. Combining literature on gender, Islam, and the state in Indonesia with new material such as divorce rates, cases of the Constitutional Court, and law reform initiatives, the authors argue that the family law reform processes already underway before 1998 have not changed much and have continued to lead to more state control of Islamic family law. Yet, even though the reforms since 1998 have not directly targeted family law, they have unleashed processes of liberalization, democratization and decentralization that have emboldened Indonesian women in the exercise of their rights and have invigorated debates over further reform.

Anatomy, cranial ontogeny and phylogenetic relationships of the pareiasaurDeltavjatia rossicusfrom the Late Permian of central Russia

2013 ◽  
Vol 104 (2) ◽  
pp. 81-122 ◽  
Author(s):  
Linda A. Tsuji
Keyword(s):  
Bayesian Methods ◽  
Size Range ◽  
Bayesian Analyses ◽  
Geometric Morphometric ◽  
Skull Roof ◽  
Central Russia ◽  
New Material ◽  
Geometric Morphometric Analysis ◽  
Cranial Ontogeny ◽  
Wide Size Range

ABSTRACTNew material of the pareiasaurDeltavjatia rossicusfrom the Kotel'nich locality, Kirov Province, Russia, is described in detail. The taxon is characterised by a distinctive pattern of dermal sculpture and the exaggerated embayment of the posterior skull roof, resulting in the dorsal exposure of the braincase. Postcranially,Deltavjatiashares some aspects of its morphology with basal pareiasaurs, including the osteoderm pattern. Features such as the forward-slanting and pointed iliac blade are shared with stratigraphically younger, more derived forms. Well-preserved material of the taxon spans a wide size-range, allowing an assessment of ontogenetic trends. A geometric morphometric analysis of the skull roof ofDeltavjatiareveals an allometric increase in snout length and postorbital area, a result that can serve as a basis for examining morphological trends within pareiasaurs. A reassessment of pareiasauromorph relationships, using both parsimony and Bayesian methods of phylogenetic inference, recovers similar topologies in both cases. Four Bayesian analyses were completed, with and without a gamma-shaped parameter and with and without the inclusion of autapomorphies. Despite differing taxon and outgroup selection, the recovered topologies are similar to previous phylogenies of pareiasaurian relationships, withDeltavjatiaappearing as a relatively basal taxon.

Non-Normative Events and Family Functioning: The Role of the Family Psychologist

1993 ◽  
Author(s):  
Michele Harway ◽  
◽  
Nancy Boyd-Franklin ◽  
Robert Geffner ◽  
Marsali Hansen ◽  
...  
Keyword(s):  
Family Functioning ◽  
The Family

Mental Health of War-Affected Youth in Two Conflicts: The Role of the Family, Community and Classroom

2008 ◽  
Author(s):  
Ivelina Borisova ◽  
Theresa Betancourt ◽  
Wietse Tol ◽  
Ivan Komproe ◽  
Mark Jordans ◽  
...  
Keyword(s):  
Mental Health ◽  
The Family
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