scholarly journals Osteohistology of Late Triassic prozostrodontian cynodonts from Brazil

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e5029 ◽  
Author(s):  
Jennifer Botha-Brink ◽  
Marina Bento Soares ◽  
Agustín G. Martinelli

The Prozostrodontia includes a group of Late Triassic-Early Cretaceous eucynodonts plus the clade Mammaliaformes, in which Mammalia is nested. Analysing their growth patterns is thus important for understanding the evolution of mammalian life histories. Obtaining material for osteohistological analysis is difficult due to the rare and delicate nature of most of the prozostrodontian taxa, much of which comprises mostly of crania or sometimes even only teeth. Here we present a rare opportunity to observe the osteohistology of several postcranial elements of the basal prozostrodontid Prozostrodon brasiliensis, the tritheledontid Irajatherium hernandezi, and the brasilodontids Brasilodon quadrangularis and Brasilitherium riograndensis from the Late Triassic of Brazil (Santa Maria Supersequence). Prozostrodon and Irajatherium reveal similar growth patterns of rapid early growth with annual interruptions later in ontogeny. These interruptions are associated with wide zones of slow growing bone tissue. Brasilodon and Brasilitherium exhibit a mixture of woven-fibered bone tissue and slower growing parallel-fibered and lamellar bone. The slower growing bone tissues are present even during early ontogeny. The relatively slower growth in Brasilodon and Brasilitherium may be related to their small body size compared to Prozostrodon and Irajatherium. These brasilodontids also exhibit osteohistological similarities with the Late Triassic/Early Jurassic mammaliaform Morganucodon and the Late Cretaceous multituberculate mammals Kryptobaatar and Nemegtbaatar. This may be due to similar small body sizes, but may also reflect their close phylogenetic affinities as Brasilodon and Brasilitherium are the closest relatives to Mammaliaformes. However, when compared with similar-sized extant placental mammals, they may have grown more slowly to adult size as their osteohistology shows it took more than one year for growth to attenuate. Thus, although they exhibit rapid juvenile growth, the small derived, brasilodontid prozostrodontians still exhibit an extended growth period compared to similar-sized extant mammals.

Fossil Record ◽  
2018 ◽  
Vol 21 (1) ◽  
pp. 137-157 ◽  
Author(s):  
Nicole Klein ◽  
Eva Maria Griebeler

Abstract. Bone tissue, microanatomy, and growth are studied in humeri of the pachypleurosaurs Dactylosaurus from the early Anisian of Poland and of aff. Neusticosaurus pusillus from the Lettenkeuper (early Ladinian) of southern Germany. Histology and modeled growth curves are compared to already published data of other pachypleurosaurs. Therefore, we herein established growth curves for Anarosaurus from the middle Anisian of Winterswijk (the Netherlands) and for pachypleurosaurs from the Anisian/Ladinian of the Alpine Triassic (i.e., Neusticosaurus spp. and Serpianosaurus). Humeri of Dactylosaurus, Anarosaurus, and aff. N. pusillus, all from the Germanic Basin, usually display an inner ring of (pre-)hatchling bone tissue. In some samples this tissue is surrounded by a layer of perpendicularly oriented fine fibers, which could indicate the start of active locomotion for foraging or might be related to viviparity. However, pachypleurosaurs from the Alpine Triassic do not show this tissue. This in turn could be related to overall differences in the environments inhabited (Germanic Basin vs. Alpine Triassic). Histological comparison revealed distinct taxon-specific differences in microanatomy and bone tissue type between Anarosaurus on the one hand and Dactylosaurus and the Neusticosaurus–Serpianosaurus clade on the other hand. Microanatomical differences imply a different degree in secondary adaptation to an aquatic environment. Life-history traits derived histologically and obtained from modeling growth were in general rather similar for all studied pachypleurosaurs. Onset of sexual maturation was within the first third of life. Asymptotic ages (maximum life span) considerably exceeded documented and modeled ages at death in all pachypleurosaur taxa. All traits modeled (more or less) matched values seen in similar-sized extant reptiles. Growth curves revealed differences in growth and maturation strategies within taxa that could indicate sexual dimorphism expressed in different adult sizes and a different onset of sexual maturation. Differences in gender size and morphology is well documented for the Chinese pachypleurosaur Keichousaurus and for Neusticosaurus spp. from the Alpine Triassic. Birth-to-adult size ratios of herein studied pachypleurosaurs were consistent with those seen in other viviparous Sauropterygia, other viviparous extinct taxa as well as extant viviparous reptiles. Anarosaurus had the highest maximum growth rates of all pachypleurosaurs studied, which best conformed to those seen in today's similar-sized reptiles and is expected from its bone tissue type. The other pachypleurosaur taxa had lower rates than the average seen in similar-sized extant reptiles. We hypothesize from our data that the considerably higher asymptotic ages compared to ages at death, early onset of maturation compared to asymptotic age, and viviparity reflect that pachypleurosaurs lived in predator-dominated environments.


Science ◽  
2018 ◽  
Vol 363 (6422) ◽  
pp. 78-80 ◽  
Author(s):  
Tomasz Sulej ◽  
Grzegorz Niedźwiedzki

Here, we describe the dicynodontLisowicia bojani, from the Late Triassic of Poland, a gigantic synapsid with seemingly upright subcursorial limbs that reached an estimated length of more than 4.5 meters, height of 2.6 meters, and body mass of 9 tons.Lisowiciais the youngest undisputed dicynodont and the largest nondinosaurian terrestrial tetrapod from the Triassic. The lack of lines of arrested growth and the highly remodeled cortex of its limb bones suggest permanently rapid growth and recalls that of dinosaurs and mammals. The discovery ofLisowiciaoverturns the established picture of the Triassic megaherbivore radiation as a phenomenon restricted to dinosaurs and shows that stem-group mammals were capable of reaching body sizes that were not attained again in mammalian evolution until the latest Eocene.


Author(s):  
Peng Bun Ngor ◽  
Ratha Sor ◽  
Leang Hour Prak ◽  
Nam So ◽  
Zeb S. Hogan ◽  
...  

Molluscs are important for ecological function, livelihoods and fisheries, but are often forgotten in research and management. Here, we investigated intra-annual variation in the landing and growth patterns of three mollusc species, i.e., Corbicula moreletiana, Pila virescens and Pila ampullacea, using one-year daily data on landing catches and values, recorded in Kampong Chhnang province of Tonle Sap (TS) Lake. Overall, 8330 tonnes with a first sale landing value of US$ 1.4 million for the three species were reported. Also, we found that C. moreletiana was abundant during the dry season with high temperature and less precipitation. By contrast, the two Pila species were abundant from the early rainy to early dry seasons when precipitation and water levels increase. The length–weight relationship analysis indicated that a faster growth in weight of Pila species occurred in the rainy season, and a general negative allometric growth was observed for the three species. This implies that their populations were intensively fished. Our preliminary results suggest that molluscs in the TS Lake (i) are important resources in support of people's livelihoods, (ii) respond differently to intra-annual variation in temperature, precipitation and hydrology and (iii) are being intensively exploited with significant reduction in growth rate. Therefore, it is necessary to conduct further comprehensive research describing status of mollusc stocks and their ecology to support long-term management and conservation of this important aquatic fauna. Our study contributes to establishing the first important baseline data and information on key mollusc species for the TS.


2006 ◽  
Vol 66 (1a) ◽  
pp. 85-93 ◽  
Author(s):  
M. I. Hamann

From December 1995 to November 2000, the seasonal maturation of Glypthelmins vitellinophilum Dobbin, 1958, in its definitive host, the frog Lysapsus limellus Cope, 1862, was studied in a subtropical permanent pond in northeastern Argentina. The objectives of this study were: 1) to determine the infrapopulation dynamics of the parasite, analyzing the seasonal maturation cycle throughout the years; and 2) to examine the relationship between the intensity of trematode infection in different developmental stages (recruitment, growth and maturation) and the host's body length. Of a total of 1,400 frogs examined over 60 months (5 years), 38% were found to be infected with G. vitellinophilum, and the intensity of infection was 1-15 trematodes per frog. Specimens of G. vitellinophilum were present in L. limellus throughout the years, but did not show a pronounced seasonal maturation cycle. Possible reasons for these findings are discussed with reference to climatic fluctuations and biotic factors. The infective period of the parasite (stage I) occurred in summer, autumn and spring, coinciding with the time each frog cohort appeared. These infections were found principally in small body sizes (classes 1 and 2) of L. limellus. Juvenile and nongravid specimens of worms (stage II and III) were found in frogs of different body sizes throughout the period of investigation. Gravid specimens of the parasite (stage IV) were generally recorded in autumn, winter and spring, mainly in the bodies of larger frogs. The body length of Trematodes in stages I and IV was significantly and positively correlated with that of the frogs.


2020 ◽  
Author(s):  
Scott Hotaling ◽  
Joanna L. Kelley ◽  
Paul B. Frandsen

AbstractAquatic insects comprise 10% of all insect diversity, can be found on every continent except Antarctica, and are key components of freshwater ecosystems. Yet aquatic insect genome biology lags dramatically behind that of terrestrial insects. If genomic effort was spread evenly, one aquatic insect genome would be sequenced for every ∼9 terrestrial insect genomes. Instead, ∼24 terrestrial insect genomes have been sequenced for every aquatic insect genome. This discrepancy is even more dramatic if the quality of genomic resources is considered; for instance, while no aquatic insect genome has been assembled to the chromosome level, 29 terrestrial insect genomes spanning four orders have. We argue that a lack of aquatic insect genomes is not due to any underlying difficulty (e.g., small body sizes or unusually large genomes) yet it is severely hampering aquatic insect research at both fundamental and applied scales. By expanding the availability of aquatic insect genomes, we will gain key insight into insect diversification and empower future research for a globally important taxonomic group.Simple SummaryAquatic insects comprise 10% of all insect diversity, can be found on every continent except Antarctica, and are key components of freshwater ecosystems. Yet aquatic insect genome biology lags dramatically behind that of terrestrial insects. If genomic effort was spread evenly, one aquatic insect genome would be sequenced for every ∼9 terrestrial insect genomes. Instead, ∼24 terrestrial insect genomes have been sequenced for every aquatic insect genome. We argue that the limited availability of aquatic insect genomes is not due to practical limitations—e.g., small body sizes or overly complex genomes—but instead reflects a lack of research interest. We call for targeted efforts to expand the availability of aquatic insect genomic resources to gain key molecular insight into insect diversification and empower future research.


2017 ◽  
pp. 5
Author(s):  
Emmanuel Rincón ◽  
Pilar Huante ◽  
Mariana Álvarez-Añorve

The objective of this study is to assess the biomass allocation pattern s and growth characteristics of three species of Caesalpinia (Leguminosae) from the highly diverse and seasonal Chamela tropical deciduous forest , where the plant growth period is restricted to the rainy season. The studied species, although they are phylogenetically related, presented different biomass al location patterns and RGR during growth, in order to carry out a differential exploitation of resources and to promote their coexistence. There were differences in relative growth rate (RGR), root to shoot ratio (R/ S), net assimilation rate (E), biomass allocation patterns and total biomass and leaf area attained among the studied species. Caesalpinia eriostachys and C. platyloba showed similar growth patterns between them but contrasting with those of C. sclerocarpa. This suggests a temporal uncuopling of their maximum resource demand. RGR was determined to a greater extent by parameters related with E than by parameters related with the specific leaf area (SLA).


1995 ◽  
Vol 32 (4) ◽  
pp. 282-289
Author(s):  
Minoru Arakaki ◽  
Shunichi Yamashita ◽  
Mehmet Mutaf ◽  
Shinji Naito ◽  
Tohru Fujii

We investigated how a new type of synthetic porous hydroxyapatite ceramic (HAP-TCP) acts when it is implanted in growing membranous bone. Seventy-six New Zealand White infant male rabbits (4-week-olds) were used. Rabbits received HAP-TCP block or silicone block implantation in their right nasal bone. The left nasal bone was used for a sham. Serial or cross-sectional examinations by morphometry, radiology, blood biochemistry, and histology were carried out. Both the HAP-TCP and silicone groups exhibited no systemic growth disturbance in terms of morphometry and blood biochemistry. Dual energy x-ray absorptiometry (DEXA) revealed, however, a decrease in the bone mineral content (BMC) of the right nasal bone in the silicone group. Histology revealed a superior affinity of HAP-TCP to bone tissue than that of silicone. When a HAP-TCP block was implanted under the periosteum it bonded directly to bone tissue. However, sinking of the implants into the bone tissue were noted both in the HAP-TCP and the silicone groups in longitudinal observation. These results suggest that although HAP-TCP has superior affinity to bone tissue, this by itself is not enough sufficient reason to believe that HAP-TCP can be effectively applied during the growth period.


The Condor ◽  
2002 ◽  
Vol 104 (4) ◽  
pp. 885-890 ◽  
Author(s):  
Rajarathinavelu Nagarajan ◽  
Krishinamoorthy Thiyagesan ◽  
Rajagopalan Natarajan ◽  
Ramalingam Kanakasabai

Abstract We examined nestling growth patterns of the Indian Barn-Owl (Tyto alba stertens) in Tamilnadu, Southern India, with reference to body mass, body length, bill length, bill width, wing length, wingspan, tail length, tarsus length, and middle claw length. Body mass reached an asymptote of 447.0 ± 6.8 g during week 7, which was 10% higher than the adult mass. Then it significantly declined to 437.0 ± 10.9 g at fledging. At the end of week 4, the body length, bill length, bill width, tarsus length, and middle toe length had surpassed 50% of adult sizes. The wingspan and tarsus length reached almost adult size by the time of fledging. A logistic growth curve was found to be a good fit for all the growth variables and explained between 71% (wing length) and 86% (body length) of the variance. Patrones de Crecimiento en Polluelos de Tyto alba stertens Resumen. Examinamos los patrones de crecimiento de polluelos de Tyto alba stertens en Tamilnadu, sudoeste de India, en relación al peso y el largo del cuerpo, el largo y el ancho del pico, el largo del ala y su envergadura, y el largo de la cola, los tarsos y de la garra mediana. El peso corporal alcanzó una asíntota de 447.0 ± 6.8 g durante la séptima semana, el cual fue un 10% mayor que el peso de los adultos. Posteriormente, durante el período de volantones, el peso corporal disminuyó hasta 437.0 ± 10.9 g. Al final de la cuarta semana, el largo del cuerpo, el largo y el ancho del pico, y los largos del tarso y del dedo mediano habían sobrepasado el 50% de los tamaños adultos. La envergadura del ala y el largo del tarso casi alcanzaron tamaños adultos durante el período de volantones. Se encontró que una curva de crecimiento logístico se ajustó bien a todas las variables de crecimiento y explicó un 71% (largo del ala) y un 86% (largo del cuerpo) de la varianza.


2019 ◽  
Vol 19 (1) ◽  
Author(s):  
Beatriz Diaz Pauli ◽  
Sarah Garric ◽  
Charlotte Evangelista ◽  
L. Asbjørn Vøllestad ◽  
Eric Edeline

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