scholarly journals Bill disparity and feeding strategies among fossil and modern penguins

Paleobiology ◽  
2020 ◽  
Vol 46 (2) ◽  
pp. 176-192 ◽  
Author(s):  
Martín Chávez-Hoffmeister
Keyword(s):  
Feeding Habits ◽  
Feeding Strategies ◽  
Aquatic Birds ◽  
Crown Group ◽  
Geometric Morphometric ◽  
Modern Analogue ◽  
Bill Morphology ◽  
Living Species ◽  
Western Grebe ◽  
Important Shift

AbstractOne of the most remarkable differences between Paleogene penguins and their living relatives is the shape and length of their beaks. Many of the Eocene and Oligocene penguins have a thin and elongated spear-like bill, which contrasts with the proportionally shorter and more robust bill of most living species. These differences suggest an important shift in their feeding strategies. This study explores the morphological disparity on the skull of penguins, emphasizing bill morphology and it relationship with feeding habits. For this, the skulls of 118 species of aquatic birds, including 21 fossil and living penguins, were analyzed using two-dimensional geometric morphometric. The results show that, unlike what has been reported for modern birds overall, in penguins and Aequornithes, bill elongation is related to a reduction of the braincase. The discriminant analysis shows that there are significant differences between penguins that feed near or far from the coast and between those that consume nectonic and planktonic prey, identifying Madrynornis as the only extinct form with a possibly planktonic diet. Additionally, it is clear that Paleogene penguins occupy a region of morphospace unexplored by most diving birds, with the western grebe being their closest modern analogue. This is consistent with the hypothesis that giant penguins hunted by harpooning and not by biting as living forms do, signaling a significant change in the habits of those birds leading to the emergence of their crown group.

scholarly journals Can mandible morphology help predict feeding habits in Antarctic amphipods?

2020 ◽  
Vol 32 (6) ◽  
pp. 496-507
Author(s):  
Loïc N. Michel ◽  
Fabienne L. Nyssen ◽  
Patrick Dauby ◽  
Marie Verheye
Keyword(s):  
Functional Groups ◽  
Trophic Ecology ◽  
Feeding Habits ◽  
Gut Contents ◽  
Ecological Niches ◽  
Feeding Strategies ◽  
Generalist Predators ◽  
Dietary Specialization ◽  
Important Place ◽  
Antarctic Amphipod

AbstractIn Antarctica, amphipods form a highly diverse group, occupy many different ecological niches and hold an important place in food webs. Here, we aimed to test whether differences in Antarctic amphipod feeding habits were reflected in their mandible morphology, and if mouthpart specialization could be used to describe amphipod trophic ecology. To do so, we compared mandible morphology in nine species spanning seven families and five functional groups (grazers, suspension feeders, generalist predators, specialist predators and scavengers). Mandible morphology adequately depicted some aspects of amphipod trophic ecology, such as the trophic level at which animals feed or their degree of dietary specialization. On the other hand, links between mandible morphology and amphipod diet were seldom unambiguous or straightforward. Similar adaptations were found in distinct functional groups. Conversely, mandible morphology could vary within a single functional group, and phylogenetic effects sometimes complicated the interpretation of form-function relationships. Overall, mandible morphology on its own was generally not sufficient to precisely predict amphipod feeding strategies. However, when combined with other methods (e.g. gut contents, trophic markers), it constitutes a valuable source of information for integrative studies of amphipod ecological diversity in the Southern Ocean.

scholarly journals A revision of the genus Olivancillaria (Mollusca: Olividae) from the southwestern Atlantic

Zootaxa ◽  
2011 ◽  
Vol 2889 (1) ◽  
pp. 1 ◽  
Author(s):  
VALERIA TESO ◽  
GUIDO PASTORINO
Keyword(s):  
Geographic Distribution ◽  
Morphometric Analysis ◽  
Field Observations ◽  
Southwestern Atlantic ◽  
Sem Images ◽  
Geometric Morphometric ◽  
Size And Shape ◽  
Egg Capsules ◽  
Living Species ◽  
Geometric Morphometric Analysis

The genus Olivancillaria is revised and restricted to eight living species: O. deshayesiana, O. carcellesi, O. urceus, O. contortuplicata, O. orbignyi, O. teaguei, O. auricularia and O. vesica. The last two species were previously considered as subspecies. The name O. uretai is a junior synonym of O. orbignyi. The genus Olivancillaria is endemic to the southwestern Atlantic, ranging from Bahia state, Brazil (~12°S) to Chubut province (42°37’S), Argentina, intertidal to 70 m depth. It is a clear representative of the Argentine Malacological province. Redescriptions and re-illustration of types were done for each species. Shell ultrastructure, radulae, penes, siphon papillae and egg capsules are described and illustrated by SEM images. A geometric morphometric analysis was carried out to confirm shell variation on size and shape among species. The geographic distribution of each species is provided based on field observations as well as on museum records.

scholarly journals Genomic consequences of dietary diversification and parallel evolution due to nectarivory in leaf-nosed bats

GigaScience ◽  
2020 ◽  
Vol 9 (6) ◽  
Author(s):  
Yocelyn T Gutiérrez-Guerrero ◽  
Enrique Ibarra-Laclette ◽  
Carlos Martínez del Río ◽  
Josué Barrera-Redondo ◽  
Eria A Rebollar ◽  
...  
Keyword(s):  
Positive Selection ◽  
Evolutionary Dynamics ◽  
Feeding Habits ◽  
Parallel Evolution ◽  
Gene Families ◽  
Feeding Strategies ◽  
Phylogenomic Analysis ◽  
Glucose Content ◽  
Nectar Feeding ◽  
Dietary Diversification

Abstract Background The New World leaf-nosed bats (Phyllostomids) exhibit a diverse spectrum of feeding habits and innovations in their nutrient acquisition and foraging mechanisms. However, the genomic signatures associated with their distinct diets are unknown. Results We conducted a genomic comparative analysis to study the evolutionary dynamics related to dietary diversification and specialization. We sequenced, assembled, and annotated the genomes of five Phyllostomid species: one insect feeder (Macrotus waterhousii), one fruit feeder (Artibeus jamaicensis), and three nectar feeders from the Glossophaginae subfamily (Leptonycteris yerbabuenae, Leptonycteris nivalis, and Musonycteris harrisoni), also including the previously sequenced vampire Desmodus rotundus. Our phylogenomic analysis based on 22,388 gene families displayed differences in expansion and contraction events across the Phyllostomid lineages. Independently of diet, genes relevant for feeding strategies and food intake experienced multiple expansions and signatures of positive selection. We also found adaptation signatures associated with specialized diets: the vampire exhibited traits associated with a blood diet (i.e., coagulation mechanisms), whereas the nectarivore clade shares a group of positively selected genes involved in sugar, lipid, and iron metabolism. Interestingly, in fruit-nectar–feeding Phyllostomid and Pteropodids bats, we detected positive selection in two genes: AACS and ALKBH7, which are crucial in sugar and fat metabolism. Moreover, in these two proteins we found parallel amino acid substitutions in conserved positions exclusive to the tribe Glossophagini and to Pteropodids. Conclusions Our findings illuminate the genomic and molecular shifts associated with the evolution of nectarivory and shed light on how nectar-feeding bats can avoid the adverse effects of diets with high glucose content.

Dimorphisme sexuel et régime alimentaire de l'hermine dans un agrosystème du Québec

1984 ◽  
Vol 62 (4) ◽  
pp. 594-600 ◽  
Author(s):  
Michel Raymond ◽  
Jean-Marie Bergeron ◽  
Yves Plante
Keyword(s):  
Feeding Habits ◽  
Microtus Pennsylvanicus ◽  
Feeding Strategies ◽  
Important Food ◽  
Meadow Voles ◽  
Blarina Brevicauda ◽  
Food Components ◽  
Dimorphisme Sexuel ◽  
Sorex Cinereus ◽  
Males And Females

Variations in the diet of the ermin (Mustela erminea) were studied from 1978 to 1980 in relation to the relative availability of meadow voles (Microtus pennsylvanicus), the dominant mammal of Southern Quebec agrosystems. The analysis of 328 ermine scat samples showed that the vole does constitute the main prey item, but that the masked shrew (Sorex cinereus), the short-tailed shrew (Blarina brevicauda), and various birds are also important food components. Male ermins have more flexible feeding habits than females, who eat mostly meadow voles whatever their relative abundance. Both males and females fail to make full use of the shrews and avoid prey that weigh more than 50 g. Overlap of their realized alimentary niches is thus considerable except when small mammals are scarce. In that case, males and females use different feeding strategies; however, the hypothesis suggested by J. H. Brown and R. C. Lasiewsky (1972. Ecology, 53: 939–943) does not seem to be confirmed. The evolution of size dimorphism in this small mustelid is discussed; our results confirm the intra-sexual selection hypothesis proposed independantly by S. Erlinge (1979. Oikos, 33: 233–245) and P. J. Moors (1980. Oikos, 34: 147–158).[Journal translation]

scholarly journals First gut contents in a Cretaceous sea turtle

2005 ◽  
Vol 2 (1) ◽  
pp. 113-115 ◽  
Author(s):  
Benjamin P Kear
Keyword(s):  
Direct Evidence ◽  
Feeding Habits ◽  
Sea Turtles ◽  
Sea Turtle ◽  
Benthic Invertebrate ◽  
The Body ◽  
Gut Contents ◽  
Feeding Strategies ◽  
Shell Fragments ◽  
Correct Size

Modern sea turtles utilize a variety of feeding strategies ranging from herbivory to omnivory. In contrast, the diets of fossil sea turtles are poorly known. This study reports the first direct evidence: inoceramid bivalve shell pieces (encased in phosphatic material) preserved within the body cavities of several small protostegid turtles (cf. Notochelone ) from the Lower Cretaceous of Australia. The shell fragments are densely packed and approximately 5–20 mm across. Identical shell accumulations have been found within coprolite masses from the same deposits; these are of a correct size to have originated from Notochelone , and indicate that benthic molluscs were regular food items. The thin, flexible inoceramid shells (composed of organic material integrated into a prismatic calcite framework) appear to have been bitten into segments and ingested, presumably in conjunction with visceral/mantle tissues and encrusting organisms. Although protostegids have been elsewhere interpreted as potential molluscivores, their primitive limb morphology is thought to have limited them to surface feeding. However, the evidence here that at least some forms were able to utilize benthic invertebrate prey indicates that, like modern sea turtles, protostegids probably exhibited a much broader range of feeding habits.

scholarly journals Distribution of α amylase along the alimentary tract of two Mediterranean fish species, the parrotfish Sparisoma cretense L. and the stargazer, Uranoscopus scaber L

2003 ◽  
Vol 4 (2) ◽  
pp. 115 ◽  
Author(s):  
E.S. PAPOUTSOGLOU ◽  
A.R. LYNDON
Keyword(s):  
Fish Species ◽  
Alimentary Tract ◽  
Feeding Habits ◽  
Anterior Part ◽  
Alpha Amylase ◽  
Feeding Strategies ◽  
Posterior Intestine ◽  
Pyloric Caeca ◽  
Lack Of Information ◽  
Uranoscopus Scaber

There is very little information available for the only Mediterranean species of parrotfish ( Sparisoma cretense) and its feeding habits, especially since most other parrotfish species are associated with coral reefs. The same lack of information is true for another fish species, the stargazer ( Uranoscopus scaber), which is carnivorous, and important for local fisheries in the Mediterranean. Comparative information is presented concerning the digestive activity and capacity for alpha amylase for these species with completely different feeding strategies, as well as main location(s) of carbohydrate digestion along their digestive tract. Alphaamylase activity and capacity is significantly higher in S. cretensethan U. scaber(p<0.05). Activity in S. cretense is very high, comparable to levels reported for carp and tilapia. It is similar in anterior and posterior intestine, however, the posterior intestine comprises a more important role in alpha amylase capacity. In U. scaber, activity is present in pyloric caeca and intestine. Levels are very low, comparable to levels reported for other benthic marine carnivores. There is no difference between activities in intestine and pyloric caeca. However, activity is higher in the anterior part of the intestine, lower in the posterior intestine and absent in the stomach. Such information is thought to be beneficial for improving knowledge on the biology of the examined species, and the physiology of nutrition, as well as for assisting towards understanding these processes in other, more valuable species for aquaculture. Also, the possibility of using the stargazer alimentary tract, especially its pyloric caeca as a model system is discussed.

A phylogeny and timescale for the living genera of kangaroos and kin (Macropodiformes:Marsupialia) based on nuclear DNA sequences

2008 ◽  
Vol 56 (6) ◽  
pp. 395 ◽  
Author(s):  
Robert W. Meredith ◽  
Michael Westerman ◽  
Mark S. Springer
Keyword(s):  
Dna Sequences ◽  
Nuclear Dna ◽  
Late Eocene ◽  
Ancestral State ◽  
Crown Group ◽  
Protein Coding ◽  
Early Oligocene ◽  
Ecological Changes ◽  
Living Species ◽  
Divergence Estimates

Kangaroos and kin (Macropodiformes) are the most conspicuous elements of the Australasian marsupial fauna. The approximately 70 living species can be divided into three families: (1) Hypsiprymnodontidae (the musky rat kangaroo); (2) Potoroidae (potoroos and bettongs); and (3) Macropodidae (larger kangaroos, wallabies, banded hare wallaby and pademelons). Here we examine macropodiform relationships using protein-coding portions of the ApoB, BRCA1, IRBP, Rag1 and vWF genes via maximum parsimony, maximum likelihood and Bayesian methods. We estimate times of divergence using two different relaxed molecular clock methods to present a timescale for macropodiform evolution and reconstruct ancestral states for grades of dental organisation. We find robust support for a basal split between Hypsiprymnodontidae and the other macropodiforms, potoroid monophyly and macropodid monophyly, with Lagostrophus as the sister-taxon to all other macropodids. Our divergence estimates suggest that kangaroos diverged from Phalangeroidea in the early Eocene, that crown-group Macropodiformes originated in the late Eocene or early Oligocene and that the potoroid–macropodid split occurred in the late Oligocene or early Miocene followed by rapid cladogenesis within these families 5 to 15 million years ago. These divergence estimates coincide with major geological and ecological changes in Australia. Ancestral state reconstructions for grades of dental organisation suggest that the grazer grade evolved independently on two different occasions within Macropodidae.

The Origin and Evolutionary Biology of Pinnipeds: Seals, Sea Lions, and Walruses

2018 ◽  
Vol 46 (1) ◽  
pp. 203-228 ◽  
Author(s):  
Annalisa Berta ◽  
Morgan Churchill ◽  
Robert W. Boessenecker
Keyword(s):  
North Pacific ◽  
Evolutionary Biology ◽  
Breeding Systems ◽  
Feeding Strategies ◽  
Crown Group ◽  
Sea Lions ◽  
The North ◽  
Fur Seals ◽  
Body Sizes ◽  
The North Pacific

The oldest definitive pinniped fossils date from approximately 30.6–23 million years ago (Ma) in the North Pacific. Pinniped monophyly is consistently supported; the group shares a common ancestry with arctoid carnivorans, either ursids or musteloids. Crown pinnipeds comprise the Otariidae (fur seals and sea lions), Odobenidae (walruses), and Phocidae (seals), with paraphyletic “enaliarctines” falling outside the crown group. The position of extinct Desmatophocidae is debated; they are considered to be closely related to both otariids and odobenids or, alternatively, to phocids. Both otariids and odobenids are known from the North Pacific, diverging approximately 19 Ma, with phocids originating in the North Atlantic or Paratethys region 19–14 Ma. Our understanding of pinniped paleobiology has been enriched by studies that incorporate anatomical and behavioral data into a phylogenetic framework. There is now evidence for sexual dimorphism in the earliest pinnipeds, heralding polygynous breeding systems, followed by increased body sizes, diving capabilities, and diverse feeding strategies in later-diverging phocid and otarioid lineages.

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