scholarly journals Cryptic niche switching in a chemosymbiotic gastropod

2018 ◽  
Vol 285 (1882) ◽  
pp. 20181099 ◽  
Author(s):  
Chong Chen ◽  
Katrin Linse ◽  
Katsuyuki Uematsu ◽  
Julia D. Sigwart
Keyword(s):  
Marine Animals ◽  
Internal Organs ◽  
Growth Series ◽  
Energy Dynamics ◽  
Pelagic Larvae ◽  
Body Change ◽  
Trophic Shift ◽  
Body Sizes ◽  
Sudden Transition ◽  
Sexually Mature

Life stages of some animals, including amphibians and insects, are so different that they have historically been seen as different species. ‘Metamorphosis’ broadly encompasses major changes in organism bodies and, importantly, concomitant shifts in trophic strategies. Many marine animals have a biphasic lifestyle, with small pelagic larvae undergoing one or more metamorphic transformations before settling into a permanent, adult morphology on the benthos. Post-settlement, the hydrothermal vent gastropod Gigantopelta chessoia experiences a further, cryptic metamorphosis at body sizes around 5–7 mm . The terminal adult stage is entirely dependent on chemoautotrophic symbionts; smaller individuals do not house symbionts and presumably depend on grazing. Using high-resolution X-ray microtomography to reconstruct the internal organs in a growth series, we show that this sudden transition in small but sexually mature individuals dramatically reconfigures the organs, but is in no way apparent from external morphology. We introduce the term ‘cryptometamorphosis’ to identify this novel phenomenon of a major body change and trophic shift, not related to sexual maturity, transforming only the internal anatomy. Understanding energy flow in ecosystems depends on the feeding ecology of species; the present study highlights the possibility for adult animals to make profound shifts in biology that influence energy dynamics.

Bone histology of two pareiasaurs from Russia (Deltavjatia rossica and Scutosaurus karpinskii) with implications for pareiasaurian palaeobiology

2019 ◽  
Author(s):  
Elizaveta A Boitsova ◽  
Pavel P Skutschas ◽  
Andrey G Sennikov ◽  
Valeriy K Golubev ◽  
Vladimir V Masuytin ◽  
...  
Keyword(s):  
Initial Period ◽  
Growth Strategy ◽  
Upper Permian ◽  
Long Bone ◽  
Ontogenetic Changes ◽  
Growth Series ◽  
Body Sizes ◽  
Porous Microstructure ◽  
Cyclical Growth ◽  
Similar Growth

Abstract Pareiasaurs were one of the main clades of large herbivorous tetrapods in Middle–Late Permian continental ecosystems. Despite abundant pareiasaur material, many aspects of their biology remain poorly known. This paper provides a description of ontogenetic changes in long-bone and rib microanatomy/histology of two Upper Permian pareiasaurs from Russia, Deltavjatia rossica and Scutosaurus karpinskii. Analysis of a growth series of bones of Deltavjatia and Scutosaurus revealed rapid and cyclical growth early in ontogeny (as indicated by fast-growing fibrolamellar bone with lines of arrested growth). This was followed by a change in the growth pattern (as indicated by an outer avascular layer of lamellar bone in the cortex) and a decrease in the growth rate after 50% of maximum body size was reached in Deltavjatia and 75% in Scutosaurus (larger body sizes in Scutosaurus were attained through an extended initial period of fast skeletal growth). The study confirms that the bones of all pareiasaurs are histologically and microanatomically uniform [spongious (porous) microstructure and a very thin compact cortex] and indicate a similar growth strategy (a short initial period of rapid and cyclical growth followed by a long period of slow growth). The microanatomical characteristics of pareiasaurs do not provide a clear indication of their lifestyle.

Use of bone histology in estimating the age of frogs (Rana perezi) from a warm temperate climate area

1996 ◽  
Vol 74 (10) ◽  
pp. 1914-1921 ◽  
Author(s):  
Marisa Esteban ◽  
Mario García-París ◽  
Jacques Castanet
Keyword(s):  
Bone Growth ◽  
Extended Period ◽  
Temperate Climate ◽  
Water Frogs ◽  
Wide Range ◽  
Body Sizes ◽  
Males And Females ◽  
Warm Temperate ◽  
Sexually Mature ◽  
Rana Perezi

The structure and the histological expression of annual bone growth marks of Iberian water frogs (Rana perezi) from a warm temperate climate region (southwestern Spain) differ markedly from the pattern observed in colder climate populations. Forty-eight percent of winter growth marks appeared to be annuli; 52% are lines of arrested growth but 20% of these are weakly expressed. Annuli or lines of arrested growth were very diffuse or absent in 7% of the 103 individuals studied, suggesting that variations in climate have a stronger influence on growth-mark formation than was previously considered. Males and females are sexually mature in their second year, although some males mature at 1 year of age and some females at 3 years. The oldest males were 4 years old, 1 year younger than males from northern populations. The oldest female was 6 years old. The wide range of body sizes among the 1-year-old froglets can be explained by the extended period of metamorphosis, from July to November.

Populations of Cane Toad, Bufo-Marinus, in Relation to Time Since Colonization

1986 ◽  
Vol 13 (2) ◽  
pp. 321 ◽  
Author(s):  
WJ Freeland
Keyword(s):  
Population Density ◽  
Average Density ◽  
Young Population ◽  
Cane Toad ◽  
Body Sizes ◽  
Capture Recapture ◽  
Single Night ◽  
Fat Bodies ◽  
Toad Bufo ◽  
Sexually Mature

A repeatable index of population density for cane toads active around permanent water in the dry season showed that, in the lowlands of the Gulf of Carpentaria, local populations rapidly increased in size following colonization, and remained high (up to 2138 ha-1 on a single night) for at least 19 years. Long-established populations ( ~ 47 years) around Townsville have declined to an average density of 82 ha-1 on a single night. In this area toads are in poor body condition, are smaller, and have a lower proportion of reproductive males than do younger populations. The sizes of fat bodies, and the numbers of ova carried by females, do not appear to have declined in the Townsville populations. The index of population density was found to represent approximately 20% of a Jolly-Seber, capture-recapture estimate of population density for a 2.5-year-old cane toad population. The Jolly-Seber estimate for this young population is up to 45 times the densities of native cane toads in Panama. The numbers of toads captured, toad body sizes and proportions of sexually mature toads in the Townsville populations are very similar to those in Panama.

On growth of the octopus Eledone cirrhosa

1982 ◽  
Vol 62 (2) ◽  
pp. 277-296 ◽  
Author(s):  
P. R. Boyle ◽  
Daniela Knobloch
Keyword(s):  
The Body ◽  
The North ◽  
Preliminary Information ◽  
In Captivity ◽  
Body Sizes ◽  
The North Sea ◽  
Wet Weight ◽  
The Mean ◽  
Specific Growth Rates ◽  
Sexually Mature

The growth of the octopus Eledone cirrhosa has been studied in a population from the North Sea off Aberdeen. Data are presented for the growth of individuals isolated in aquarium conditions; the growth of size classes in thefieldpopulation; and preliminary information on the growth relationships of gonad, somatic, cardiac and brain components of the body.At 15 °C Eledone cirrhosa is capable of growing from 10 to 1000 g in 270 days. From octopuses which feed readily in captivity, weight specific growth rates of up to about 3–5 % day-1 for animals of 100 g body weight are recorded, falling to a maximum of about 1–5 % day-1 at body sizes above 500 g. Females stop growing when sexually mature, but in the sample captured they were consistently larger than males, a feature which may account for the 7:1 bias towards the incidence of females. On a wet-weight basis, the mean food incorporation into growth is 37 % of the food ingested, which is 49% of the gross weight of crabs killed. Field data for 1978/79 suggest that animals recruited to the population at the beginning of the year grew steadily until December, overwintered without growing, then grew rapidly for several months in the subsequent year before disappearing from the samples. The estimated average age of those animals and by implication, the life span, is 20 months.

scholarly journals Large trilobites in a stress-free Early Ordovician environment

2020 ◽  
pp. 1-10 ◽  
Author(s):  
Farid Saleh ◽  
Muriel Vidal ◽  
Lukáš Laibl ◽  
Pierre Sansjofre ◽  
Pierre Gueriau ◽  
...  
Keyword(s):  
Body Size ◽  
Cold Water ◽  
Water Environment ◽  
Core Material ◽  
Storm Events ◽  
Geological Time ◽  
Marine Animals ◽  
Lower Ordovician ◽  
Body Sizes

Abstract Understanding variations in body size is essential for deciphering the response of an organism to its surrounding environmental conditions and its ecological adaptations. In modern environments, large marine animals are mostly found in cold waters. However, numerous parameters can influence body-size variations other than temperatures, such as oxygenation, nutrient availability, predation or physical disturbances by storms. Here, we investigate trilobite size variations in the Lower Ordovician Fezouata Shale deposited in a cold-water environment. Trilobite assemblages dominated by small- to normal-sized specimens that are a few centimetres in length are found in proximal and intermediate settings, while those comprising larger taxa more than 20 cm in length are found in the most distal environment of the Fezouata Shale. Drill core material from distal settings shows that sedimentary rocks hosting large trilobites preserved in situ are extensively bioturbated with a high diversity of trace fossils, indicating that oxygen and nutrients were available in this environment. In intermediate and shallow settings, bioturbation is less extensive and shallower in depth. The rarity of storm events (minimal physical disturbance) and the lack of predators in deep environments in comparison to shallower settings would also have helped trilobites attain larger body sizes. This highly resolved spatial study investigating the effects of numerous biotic and abiotic parameters on body size has wider implications for the understanding of size fluctuations over geological time.

Ultrastructure of the basal body apparatus in epidermal cells of a sponge larva (Aplysilla SP: Demospongiae)

1992 ◽  
Vol 50 (1) ◽  
pp. 928-929
Author(s):  
R.L. Pinto ◽  
R.M. Woollacott
Keyword(s):  
Sodium Bicarbonate ◽  
Epoxy Resin ◽  
Basal Body ◽  
Phosphate Buffer ◽  
Similar Data ◽  
Basal Apparatus ◽  
Striated Rootlet ◽  
The Common ◽  
Basal Foot ◽  
Sexually Mature

The basal body and its associated rootlet are the organelles responsible for anchoring the flagellum or cilium in the cytoplasm. Structurally, the common denominators of the basal apparatus are the basal body, a basal foot from which microtubules or microfilaments emanate, and a striated rootlet. A study of the basal apparatus from cells of the epidermis of a sponge larva was initiated to provide a comparison with similar data on adult sponges.Sexually mature colonies of Aplysillasp were collected from Keehi Lagoon Marina, Honolulu, Hawaii. Larvae were fixed in 2.5% glutaraldehyde and 0.14 M NaCl in 0.2 M Millonig’s phosphate buffer (pH 7.4). Specimens were postfixed in 1% OsO4 in 1.25% sodium bicarbonate (pH 7.2) and embedded in epoxy resin. The larva ofAplysilla sp was previously described (as Dendrilla cactus) based on live observations and SEM by Woollacott and Hadfield.

Predicting changes in distribution of a large coastal shark in the face of the strengthening East Australian Current

2020 ◽  
Vol 642 ◽  
pp. 163-177 ◽  
Author(s):  
Y Niella ◽  
AF Smoothey ◽  
V Peddemors ◽  
R Harcourt
Keyword(s):  
Austral Summer ◽  
Conservation Strategies ◽  
Limiting Factor ◽  
Commercial Fisheries ◽  
East Australian Current ◽  
Spatial And Temporal Patterns ◽  
Marine Animals ◽  
Factors Affecting ◽  
Southeastern Australia ◽  
The Face

In the face of accelerating climate change, conservation strategies will need to consider how marine animals deal with forecast environmental change as well as ongoing threats. We used 10 yr (2009-2018) of data from commercial fisheries and a bather protection program along the coast of New South Wales (NSW), southeastern Australia, to investigate (1) spatial and temporal patterns of occurrence in bull sharks and (2) environmental factors affecting bull shark occurrence along the coast of NSW. Predicted future distribution for this species was modelled for the forecast strengthening East Australian Current. Bull sharks were mostly harvested in small to larger estuaries, with average depth and rainfall responsible for contrasting patterns for each of the fisheries. There was an increase in the occurrence of bull sharks over the last decade, particularly among coastal setline fisheries, associated with seasonal availability of thermal gradients >22°C and both westward and southward coastal currents stronger than 0.15 and 0.60 m s-1, respectively, during the austral summer. Our model predicts a 3 mo increase in the availability of favourable water temperatures along the entire coast of NSW for bull sharks by 2030. This coastline provides a uniquely favourable topography for range expansion in the face of a southerly shift of warmer waters, and habitat is unlikely to be a limiting factor for bull sharks in the future. Such a southerly shift in distribution has implications for the management of bull sharks both in commercial fisheries and for mitigation of shark-human interactions.

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