scholarly journals Feeding behaviour in a ‘basal’ tortoise provides insights on the transitional feeding mode at the dawn of modern land turtle evolution

Author(s):  
Nikolay Natchev ◽  
Nikolay Tzankov ◽  
Ingmar Werneburg ◽  
Egon Heiss

Almost all extant land turtles are highly associated with terrestrial habitats and the few tortoises with high affinity to aquatic environment are found within the genus Manouria. Manouria belongs to a clade which forms the sister taxon to all remaining tortoises and is suitable to be used as a model for studying evolutionary transitions from water to land within modern turtles. We analysed the feeding behaviour of M. emys and due to its phylogenetic position, we hypothesise that the species might have retained some ancestral characteristics associated to aquatic lifestyle. We tested whether M. emys is able to feed both in aquatic and terrestrial environments as mud turtles do. In fact, M. emys repetitively tried to reach submerged food items in water, but always failed to grasp them and no suction feeding mechanism was applied. When feeding on land, M. emys showed another peculiar behaviour; it grasped food items by its jaws – a behaviour typical for aquatic or semiaquatic turtles – and not by the tongue as in the typical feeding mode in all tortoises studied so far. In M. emys, the hyolingual complex remained retracted during all food uptake sequences, but the food transport was entirely lingual based. The kinematical profile significantly differed from those described for other tortoises and from those proposed from the general models on the function of the feeding systems in lower tetrapods. We conclude that the feeding behaviour of M. emys might reflect a remnant of the primordial condition expected in the aquatic ancestor of tortoises.

2015 ◽  
Author(s):  
Nikolay Natchev ◽  
Nikolay Tzankov ◽  
Ingmar Werneburg ◽  
Egon Heiss

Almost all extant land turtles are highly associated with terrestrial habitats and the few tortoises with high affinity to aquatic environment are found within the genus Manouria. Manouria belongs to a clade which forms the sister taxon to all remaining tortoises and is suitable to be used as a model for studying evolutionary transitions from water to land within modern turtles. We analysed the feeding behaviour of M. emys and due to its phylogenetic position, we hypothesise that the species might have retained some ancestral characteristics associated to aquatic lifestyle. We tested whether M. emys is able to feed both in aquatic and terrestrial environments as mud turtles do. In fact, M. emys repetitively tried to reach submerged food items in water, but always failed to grasp them and no suction feeding mechanism was applied. When feeding on land, M. emys showed another peculiar behaviour; it grasped food items by its jaws – a behaviour typical for aquatic or semiaquatic turtles – and not by the tongue as in the typical feeding mode in all tortoises studied so far. In M. emys, the hyolingual complex remained retracted during all food uptake sequences, but the food transport was entirely lingual based. The kinematical profile significantly differed from those described for other tortoises and from those proposed from the general models on the function of the feeding systems in lower tetrapods. We conclude that the feeding behaviour of M. emys might reflect a remnant of the primordial condition expected in the aquatic ancestor of tortoises.


2015 ◽  
Author(s):  
Nikolay Natchev ◽  
Nikolay Tzankov ◽  
Ingmar Werneburg ◽  
Egon Heiss

Almost all extant land turtles are highly associated with terrestrial habitats and the few tortoises with high affinity to aquatic environment are found within the genus Manouria. Manouria belongs to a clade which forms the sister taxon to all remaining tortoises and is suitable to be used as a model for studying evolutionary transitions from water to land within modern turtles. We analysed the feeding behaviour of M. emys and due to its phylogenetic position, we hypothesise that the species might have retained some ancestral characteristics associated to aquatic lifestyle. We tested whether M. emys is able to feed both in aquatic and terrestrial environments as mud turtles do. In fact, M. emys repetitively tried to reach submerged food items in water, but always failed to grasp them and no suction feeding mechanism was applied. When feeding on land, M. emys showed another peculiar behaviour; it grasped food items by its jaws – a behaviour typical for aquatic or semiaquatic turtles – and not by the tongue as in the typical feeding mode in all tortoises studied so far. In M. emys, the hyolingual complex remained retracted during all food uptake sequences, but the food transport was entirely lingual based. The kinematical profile significantly differed from those described for other tortoises and from those proposed from the general models on the function of the feeding systems in lower tetrapods. We conclude that the feeding behaviour of M. emys might reflect a remnant of the primordial condition expected in the aquatic ancestor of tortoises.


Zootaxa ◽  
2021 ◽  
Vol 5051 (1) ◽  
pp. 346-386
Author(s):  
SÜPHAN KARAYTUĞ ◽  
SERDAR SAK ◽  
ALP ALPER ◽  
SERDAR SÖNMEZ

An attempt was made to test if Lourinia armata (Claus, 1866)—as it is currently diagnosed—represents a species complex. Detailed examination and comparisons of several specimens collected from different localities suggest that L. armata indeed represents a complex of four closely related morphospecies that can be differentiated from one another by only detailed observations. One of the four species is identified as Lourinia aff. armata and the other three species are described as new to science and named as Lourinia wellsi sp. nov., L. gocmeni sp. nov., and L. aldabraensis sp. nov. Detailed review of previous species records indicates that the genus Lourinia Wilson, 1924 is distributed worldwide. Ceyloniella nicobarica Sewell, 1940, originally described from Nicobar Island and previously considered a junior subjective synonym of L. armata is reinstated as Lourinia nicobarica (Sewell, 1940) comb. nov. on the basis of the unique paddle-shaped caudal ramus seta V. It is postulated that almost all of these records are unreliable in terms of representing true Lourinia aff. armata described herein. On the other hand, the comparative evaluation of the illustrations and descriptions in the published literature indicates the presence of several new species waiting to be discovered in the genus Lourinia.                 It has been determined that, according to updated modern keys, the recent inclusion of the monotypic genus Archeolourinia Corgosinho & Schizas, 2013 in the Louriniidae is not justified since Archeolourinia shermani Corgosinho & Schizas, 2013 does not belong to this family but should be assigned to the Canthocamptidae. On the other hand, it has been argued that the exact phylogenetic position of the Louriniidae still remains problematic since none of the diagnostic characters supports the monophyly of the family within the Oligoarthra. It has also been argued that the close relationship between Louriniidae and Canthocamptidae is supported since both families share the homologous sexual dimorphism (apophysis) on P3 endopod. The most important characteristic that can possibly be used to define Louriniidae is the reduction of maxilliped.  


2007 ◽  
Vol 85 (9) ◽  
pp. 985-993 ◽  
Author(s):  
E.E. Fraser ◽  
M.B. Fenton

Eating behaviour can vary with age, experience, and gender, as well as food hardness. This variation can contribute to intraspecific dietary differences and may result in variable definitions of optimal foraging and decreased intraspecific competition. We quantified feeding behaviour of insectivorous bats eating hard and soft mealworm-based food items based on the bats’ ability to consume and manipulate food items, consumption time, chew frequency, and total chews to consume. Adult Myotis lucifugus (LeConte, 1831) were more successful at both consuming and manipulating mealworms and consumed mealworms more quickly, with greater chew frequency and in fewer chews, than did subadults. Adults chewed mealworm viscera more frequently than did subadults but showed no differences in the other variables. Adult Eptesicus fuscus (Beauvois, 1796) consumed mealworms more quickly and with fewer chews than did subadults but showed no differences in the other variables. There were no differences between adult and subadult E. fuscus when consuming mealworm viscera. Male and female M. lucifugus did not differ significantly when eating either mealworms or mealworm viscera. There was no change in subadult consumption time of mealworms over the summer. Age-based differences in eating abilities may play a role in defining optimal foraging and dietary composition in insectivorous bats.


2002 ◽  
Vol 7 (4) ◽  
pp. 61-65 ◽  
Author(s):  
B A Lopman ◽  
Y van Duynhoven ◽  
F X Hanon ◽  
M Reacher ◽  
M Koopmans ◽  
...  

This report describes a survey of national laboratory capabilities of diagnostics and surveillance databases for foodborne viruses among the "Foodborne Viruses in Europe" consortium. All the countries have laboratories that can test for HAV antibody in human serum. Eight of the ten surveyed European countries maintain a national database of HAV cases. Food can be tested for the presence of HAV in Finland, Italy, Spain, France and Denmark. All surveyed countries have at least one laboratory that tests for Norwalk-like virus (NLV) by reverse transcriptase-polymerase chain reaction and all also have the capability to use electron microscopy. Five countries maintain a national database of NLV cases and nine maintain a national database of NLV outbreaks. Almost all participant countries have laboratories that can test for NLV in food items including shellfish.


Behaviour ◽  
2004 ◽  
Vol 141 (8) ◽  
pp. 999-1020 ◽  
Author(s):  
◽  
◽  

AbstractHerbivorous ungulates live in a spatially heterogeneous environment making foraging decisions at a range of hierarchical scales, from bite size to landscape. We investigated the factors that control intake rate in Soay sheep (Ovis aries) when discrete items of food were sparsely distributed at the feeding station scale. Within the feeding station we varied the difficulty of accessing food, distance between items of food, difficulty of finding the food and complexity of the feeding station and recorded how intake rate responded in relation to body size, mouth size and the sex of the animal. Our findings demonstrated how increasing difficulty of accessing food, and increasing complexity of the feeding station negatively affected intake rate. The expected mechanistic response that smaller animals or animals with smaller mouth size were better at handling discrete small items of food, was overridden by individual and sexual differences in behaviour. We also considered that intake rate within a feeding station could be maximised by optimising the spatial pattern of offtake, and the results clearly indicated that both sexes tended to show clustered patterns of offtake. Animals of the same sex responded in a similar way to the difficulty in handling food items; males persevered more than females and consequently were less handicaped by having larger mouths. We discussed these results in relation to behavioural and body mass differences between the sexes and animals.


2020 ◽  
pp. 359-388
Author(s):  
Spyros Sfenthourakis ◽  
Alan A. Myers ◽  
Stefano Taiti ◽  
James K. Lowry

Among crustaceans, only Amphipoda, Isopoda, and Decapoda have invaded truly terrestrial environments, but only two groups show full adaptations to live on land: the family Talitridae among the Amphipoda and the suborder Oniscidea among the Isopoda. The Talitridae occur primarily in forest leaf litter, but a number of other habitats, including caves, are recorded. Talitrids are important ecological contributors to the litter fauna, often occurring in high densities. Their adaptations to a terrestrial way of life include the retention of the mitten-shaped second gnathopods, a neotenic condition among males; the first article of antenna 2 greatly enlarged and fixed to the side of the head; and enlarged gills and pleopods often reduced, sometimes to vestigial stumps. Talitrids have a skewed world distribution being at their most diverse in New Zealand, Tasmania, and Japan/Taiwan. They occur in the Caribbean and Central America but are absent from South and North America except as introduced taxa. Their distribution is largely a result of tectonic activity during the past 150 million years and of extinctions during the Tertiary due to increasing aridity of the climate. The Oniscidea (terrestrial isopods) are the only crustaceans that have managed to adapt to almost all habitat types on land and have become the most species-rich suborder of Isopoda. Although monophyly of the Oniscidea is generally accepted, current taxonomy, based almost entirely on morphological characters, needs extensive revision. Terrestrial isopods present a number of unique adaptations to life on land, some of which result from what can be considered as pre-adaptations of ancestral marine isopods, such as egg development in a marsupium, being dorso-ventrally oblate and having a pleopodal respiration. Other crucial adaptations of Oniscidea include the water-conducting system, the structure of their cuticle, and the “covered” type of pleopodal lungs, all of which are responses to the acute problem of desiccation. They are also among the most speciose taxa in caves, some species have even returned to an aquatic life, and a few species have evolved social behavior. Oniscidea are increasingly being used in biogeographical, phylogeographical, ecological, and evolutionary research and can become model organisms for a broad range of biological studies.


2008 ◽  
Vol 68 (2) ◽  
pp. 321-328 ◽  
Author(s):  
LM. Gomiero ◽  
AG. Manzatto ◽  
FMS. Braga

The purpose of this study was to characterize the diet of the fish Brycon opalinus (Characidae) seasonally and locally, allowing for the determination of its food items and trophic relations with the aquatic and terrestrial environments. The study area encompasses three rivers (Paraibuna, Ipiranga and Grande) in the basin of the Paraibuna, southeast Brazil. Twelve monthly collections were made from January to December 2004. The degree of stomachic repletion and of accumulated visceral fat was analyzed, as was the intestinal length in each class of total length. The frequency of occurrence and the degree of food preference (DFP) of the food items of Brycon opalinus were determined by separating the vegetal and animal items, autochthonous and allochthonous, by insect order and vegetal family consumed. The frequency of occurrence of items of animal origin was found to be equivalent to that of vegetal origin, thus characterizing the omnivorism of Brycon opalinus feeding.


2005 ◽  
Vol 65 (1) ◽  
pp. 1-8 ◽  
Author(s):  
F. G Araújo ◽  
C. C Andrade ◽  
R. N Santos ◽  
A. F. G. N Santos ◽  
L. N Santos

We assessed spatial and seasonal changes in the diet of Oligosarcus hepsetus in order to describe the strategy developed by this species that allows their very high abundance in Lajes reservoir, Rio de Janeiro, Brazil. Fish samplings were carried out using gill nets, deployed during ca. 12 and 24 hours, between April 2001 and May 2002. A total of 289 individuals were examined, of which 97 showed gut contents. We used the index of relative importance (IRI) to compare probable dietary shifts, and the frequency of occurrence (% OC) to analyze possible ontogenetic influences on feeding. O. hepsetus showed carnivorous habits, feeding preferably on fish and insects, the latter of which occurred in 71.0% of the guts presenting contents. O. hepsetus consumed different items along the three reservoir zones: insects (61.0% IRI) and Cichla monoculus (38.9% IRI) in the lower zone; Lepidoptera (57.0% IRI) in the middle zone; and C. monoculus (77.0% IRI) in the upper zone. Food items changed seasonally with C. monoculus predominating in autumn 2001, and Hymenoptera and Lepidoptera in the winter. In spring almost all food was Lepidoptera (99.8% IRI), while in the summer Hemiptera dominated in the diet. In autumn 2002 Hemiptera (97.0% IRI) was dominant, in significant contrast with the previous autumn. Individuals smaller than 190 mm SL fed heavily on insects, while fishes predominated in the diet of individuals larger than 190 mm SL. Shifts in prey-capture ability among length classes suggest decreasing intraspecific competition. A higher food plasticity seems to be the strategy employed by this opportunist species, which used food resources available in the reservoir.


2019 ◽  
Vol 94 (2) ◽  
pp. 366-377 ◽  
Author(s):  
Bryan M. Gee ◽  
Robert R. Reisz

AbstractNanobamus macrorhinus Schoch and Milner, 2014 is a small amphibamiform temnospondyl from the early Permian Arroyo Formation of Texas. It is most readily characterized by an elongate and partially subdivided naris. This condition is superficially reminiscent of that seen in the coeval trematopids, the group to which N. macrorhinus was originally referred to under an interpretation of the holotype as a larval form. This was discounted by later workers, but the amphibamiform affinities of the specimen were not formalized until recently. The specimen has never been described in the context of its amphibamiform affinities and remains poorly characterized, never having been sampled in a phylogenetic analysis. Here we present a complete, updated osteological description of N. macrorhinus, including an improved characterization of its unique mosaic of plesiomorphic and apomorphic features and clarification of the taxon's autapomorphies. Our analysis of the taxon's phylogenetic position within Amphibamiformes shows that N. macrorhinus was recovered as diverging after basal amphibamiforms, e.g., the micropholids, and before derived amphibamiforms, e.g., the amphibamids. This is supported by the unique mixture of retained plesiomorphies, e.g., nonforeshortened postparietals and an oval choana, and apomorphies, e.g., a narrow interorbital region and slender palatal rami of the pterygoid. These results reflect the complexity of terrestrial amphibamiform diversity and provide further insight into the evolutionary history of the lissamphibian stem in terrestrial environments.


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