Amphibious Habits Research Articles

Water wisteria genome reveals environmental adaptation and heterophylly regulation in amphibious plants.

Heterophylly is a phenomenon whereby an individual plant dramatically changes leaf shape in response to the surroundings. Hygrophila difformis (Acanthaceae; water wisteria), has recently emerged as a model plant to study heterophylly because of its striking leaf shape variation in response to various environmental factors. When submerged, H. difformis often develops complex leaves, but on land it develops simple leaves. Leaf complexity is also influenced by other factors, such as light density, humidity, and temperature. Here, we sequenced and assembled the H. difformis chromosome-level genome (scaffold N50: 60.43 Mb, genome size: 871.92 Mb), which revealed 36 099 predicted protein-coding genes distributed over 15 pseudochromosomes. H. difformis diverged from its relatives during the Oligocene climate-change period and expanded gene families related to its amphibious habit. Genes related to environmental stimuli, leaf development, and other pathways were differentially expressed in submerged and terrestrial conditions, possibly modulating morphological and physiological acclimation to changing environments. We also found that auxin plays a role in H. difformis heterophylly. Finally, we discovered candidate genes that respond to different environmental conditions and elucidated the role of LATE MERISTEM IDENTITY 1 (LMI1) in heterophylly. We established H. difformis as a model for studying interconnections between environmental adaptation and morphogenesis.

Unique and fragile diversity emerges from Brazilian caves – two new amphibious species of Xangoniscus Campos-Filho, Araujo & Taiti, 2014 (Oniscidea, Styloniscidae) from Serra do Ramalho karst area, state of Bahia, Brazil

Two new troglobitic species of Xangoniscus are described from two caves of Serra do Ramalho karst area, Bambuí geomorphological group, state of Bahia. Xangoniscus lapaensissp. nov. is described from Gruna Boca da Lapa cave, and X. loboisp. nov. from Gruna da Pingueira II cave. Both species are blind and depigmented and show amphibious habits, as observed for all species of Xangoniscus described until now. Xangoniscus lapaensissp. nov. occurs in travertine pools fed by water of the upper aquifer, and X. loboisp. nov. occurs in a small stream, an upper vadose tributary. Both species occur in fragile microhabitats. Ecological and behavioral data, conservation remarks, and IUCN conservation assessments are included to provide background data for conservation efforts in this unique karst area.

How Did Seal Lice Turn into the Only Truly Marine Insects?

Simple SummarySucking lice are permanent and obligate ectoparasites throughout their whole life cycle. Echinophthiriids escorted their mammal hosts during their passage from fully terrestrial to amphibian life. Seal lice synchronize their reproduction cycle with that of their mammalian hosts. Echinophthiriids tolerate long immersion periods and extreme hydrostatic pressures. Diving lice can reach kilometers under the surface and survive, during the months their hosts remain in the open ocean. In the present work, we describe and discuss how some of these adaptations allow seal lice to cope with the amphibious habits of their hosts and how they can help us to understand why insects are so rare in the ocean.Insects are the most evolutionarily and ecologically successful group of living animals, being present in almost all possible mainland habitats; however, they are virtually absent in the ocean, which constitutes more than 99% of the Earth’s biosphere. Only a few insect species can be found in the sea but they remain at the surface, in salt marshes, estuaries, or shallow waters. Remarkably, a group of 13 species manages to endure long immersion periods in the open sea, as well as deep dives, i.e., seal lice. Sucking lice (Phthiraptera: Anoplura) are ectoparasites of mammals, living while attached to the hosts’ skin, into their fur, or among their hairs. Among them, the family Echinophthiriidae is peculiar because it infests amphibious hosts, such as pinnipeds and otters, who make deep dives and spend from weeks to months in the open sea. During the evolutionary transition of pinnipeds from land to the ocean, echinophthiriid lice had to manage the gradual change to an amphibian lifestyle along with their hosts, some of which may spend more than 80% of the time submerged and performing extreme dives, some beyond 2000 m under the surface. These obligate and permanent ectoparasites have adapted to cope with hypoxia, high salinity, low temperature, and, in particular, conditions of huge hydrostatic pressures. We will discuss some of these adaptations allowing seal lice to cope with their hosts’ amphibious habits and how they can help us understand why insects are so rare in the ocean.

Morphological Plasticity in the Endemic Isoëtes Species from Serra dos Carajás, Amazonia, Brazil

Isoëtes cangae and Isoëtes serracarajensis (Isoetaceae) are species endemic to Carajás (Pará State, Brazil) that grow on iron-rich substrates of the Amazon basin under a seasonal rainfall regime. In addition to a few distinctive morphological traits, the species differ in terms of habitat and geographical distribution. The influence of the seasonality and habitat characteristics on quillwort morphology is poorly understood. To assess this influence, specimens from one population of I. cangae, and four populations of I. serracarajensis, were sampled in dry and rainy seasons to investigate variation among vegetative and reproductive characters. The megasporangium color, megaspore ornamentation, alae length, velum length and coverage (%), morphometry of sporangial wall cells, and polar/equatorial diameter ratio of megaspores provide consistent characters for species delimitation. The presence of stomata in I. serracarajensis is a new discovery and is related to its amphibious habit. Some characters that have been used in Isoëtes species descriptions, such as the number of leaves, leaf length, sporangium size, number of megaspores, and megaspore diameter were found to be variable. The current findings provide further information on the biology of the species and show the influence of seasonality and habitat characteristics on the morphological diversity of these lycophytes.

An outbreak of canine schistosomiasis in Utah: Acquisition of a new snail host (Galba humilis) by Heterobilharzia americana, a pathogenic parasite on the move

Parasites with complex life cycles engaging multiple host species living among different environments well-exemplify the value of a cross-cutting One Health approach to understanding fundamental concerns like disease emergence or spread. Here we provide new information regarding a pathogenic schistosome trematode parasite of both wild and domestic mammals that has recently expanded its known range from mesic/wet environments of the southeastern United States to the arid southwest. In 2018, 12 dogs living near a man-made pond in Moab, Utah, were found positive for Heterobilharzia americana, the most westerly report of this endemic North American schistosome, and the first from Utah. Raccoon scats collected near the pond were positive for H. americana eggs, and snails living near the pond's water line identified as Galba humilis shed H. americana cercariae, the first indication of natural infections in this widespread North American snail species. The susceptibility of G. humilis to H. americana was confirmed experimentally. Our studies support the existence of two variants of H. americana and emphasize the need for further investigations of lymnaeids and their compatibility with H. americana, to better define the future potential for its spread. Capture of a new species of intermediate host vector snail and construction of man-made habitats suitable for this snail have created the potential for a much more widespread animal health problem, especially for dogs and horses. H. americana will prove difficult to control because of the role of raccoons in maintaining transmission and the amphibious habits of the snail hosts of this pathogenic schistosome.

The Plants associated with aquatic and marshy environments in the state of Paraíba, northeastern Brazil

We present a list of aquatic and wetland plant species from the state of Paraíba, Brazil, based on the collections deposited in national and international herbaria. We identified 290 species belonging to 61 families. The checklist includes habit, localities of the collections in the state of Paraíba, and geographic distribution of each species. The amphibious habit was the most prevalent and the Sertão (semiarid inland region) was the region with the greatest collection effort. New occurrences have been registered for the state (14 species). Although our data reveal a high plant richness, we relate this richness to increased field expeditions.

Functional adaptive landscapes predict terrestrial capacity at the origin of limbs.

The acquisition of terrestrial, limb-based locomotion during tetrapod evolution has remained a subject of debate for more than a century1,2. Our current understanding of the locomotor transition from water to land is largely based on a few exemplar fossils such as Tiktaalik3, Acanthostega4, Ichthyostega5 and Pederpes6. However, isolated bony elements may reveal hidden functional diversity, providing a more comprehensive evolutionary perspective7. Here we analyse 40 three-dimensionally preserved humeri from extinct tetrapodomorphs that span the fin-to-limb transition and use functionally informed ecological adaptive landscapes8-10 to reconstruct the evolution of terrestrial locomotion. We show that evolutionary changes in the shape of the humerus are driven by ecology and phylogeny and are associated with functional trade-offs related to locomotor performance. Two divergent adaptive landscapes are recovered for aquatic fishes and terrestrial crown tetrapods, each of which is defined by a different combination of functional specializations. Humeri of stem tetrapods share a unique suite of functional adaptations, but do not conform to their own predicted adaptive peak. Instead, humeri of stem tetrapods fall at the base of the crown tetrapodlandscape, indicating that the capacity for terrestrial locomotion occurred with the origin of limbs. Our results suggest that stem tetrapods may have used transitional gaits5,11 during the initial stages of land exploration, stabilized by the opposing selective pressures of their amphibious habits. Effective limb-based locomotion did not arise until loss of the ancestral 'L-shaped' humerus in the crown group, setting the stage for the diversification of terrestrial tetrapods and the establishment of modern ecological niches12,13.

Facilitation of amphibious habit by physiological integration in the clonal, perennial, climbing herb Ipomoea aquatica

Physiological integration of connected ramets of clonal plants can increase clonal performance when ramets grow in contrasting microenvironments within a habitat. In amphibious clonal species, integration of ramets in different habitats, terrestrial and aquatic, is possible. This may increase performance of amphibious clones, especially under eutrophic conditions. To test this, clonal fragments consisting of two ramets of the amphibious, perennial, climbing herb Ipomoea aquatica connected by a stem were placed such that the proximal ramet was rooted in a simulated riparian community of four other species, while the distal ramet extended into a simulated aquatic habitat with open water and sediment. The connection between ramets was either left intact or severed, and 0, 5, or 25mg N L−1 was added to the aquatic habitat to simulate different degrees of eutrophication. Without added N, fragments in which the original ramets were left connected accumulated two times more total mass than fragments in which the ramets were disconnected from one another. The positive effect of connection increased two-fold with increasing N. These results were consistent with the hypotheses that physiological integration between connected terrestrial and aquatic ramets can increase clonal performance in plants and that this effect can be greater when the aquatic ramet is richer in nutrients. Connection reduced root to shoot ratio in terrestrial ramets, but increased it in aquatic ones, suggesting that physiological integration induced a division of labor in which terrestrial ramets specialized for light acquisition and aquatic ramets specialized for acquisition of nutrients. This provides the first report of increase in clonal performance and induction of division of labor due to physiological integration between ramets in different habitats.

Quaternary mollusc assemblages from the lower basin of Salado River, Buenos Aires Province: Their use as paleoenvironmental indicators

Quaternary mollusc assemblages preserved in the Salado basin are described and analyzed in order to reconstruct past environments and evaluate spatial and temporal variations. Five localities were analyzed, in which 48,998 individuals of eight continental gastropod species were recovered: Heleobia parchappii, Antillorbis nordestensis, Biomphalaria peregrina, Drepanotrema heloicum, Uncancylus concentricus, Pomacea canaliculata, Succinea meridionalis and Miradiscops brasiliensis. As well, other species typical of marine-estuarine environments have been found, among which Heleobia australis is highlighted. Based on changes in the composition and abundance of the assemblages, different environments could be recognized. Quaternary mollusc assemblages have low taxonomic heterogeneity and spatial and temporal variations. Assemblages recovered from Late Pleistocene–Early Holocene sediments are characterized by low species richness and abundance, with a single species in numerous examples. In the Middle Holocene, the shells became more constant and more diverse. Late Holocene assemblages have high species richness, freshwater, terrestrial and amphibious habits, and show some differences among different localities. Several episodes of flooding have been identified through the record of fossiliferous horizons with high density of shells, mainly Heleobia parchappii. These events that affected the area of influence of the Salado River occurred at least during the Late Holocene.

Anatomical variations in scapes of Eleocharis minima Kunth (Cyperaceae, Poales) - amphibian and Kranz species

In Cyperaceae about 1/3 of the species have Kranz anatomy and some species of Eleocharis can either present Kranzanatomy or not according to the environmental conditions, whether terrestrial (emerged) or aquatic (partly or fully submerged). Eleocharis minima has emerged and submerged scapes in the same individual. To identify the possible differences and their correlation with the environment, the anatomy of these scapes was investigated. The emerged scape is quadrangular e has four vascular bundles, and the submerged is triangular with three bundles. Both scapes (emerged and submerged) show non-Kranz anatomy in the basal region and Kranz anatomy of the eleocharoid type in the median region. In the apical region of submerged scapes occur Kranz anatomy of eleocharoid types, but in this same region of the emerged scape was observed variations in the continuity of the inner bundle sheath and may be interpreted as eleocharoid or chlorocyperoid types. The plasticity of the Kranz anatomy in Eleocharis minima and in other species of the genus is probably related to the amphibious habit. Therefore, the use of characters related to Kranz anatomy in Eleocharis in phylogenetic and evolutionary approaches should be restricted and carefully analyzed in view of its plasticity.

A basal ichthyosauriform with a short snout from the Lower Triassic of China.

The incompleteness of the fossil record obscures the origin of many of the more derived clades of vertebrates. One such group is the Ichthyopterygia, a clade of obligatory marine reptiles that appeared in the Early Triassic epoch, without any known intermediates. Here we describe a basal ichthyosauriform from the upper Lower Triassic (about 248 million years ago) of China, whose primitive skeleton indicates possible amphibious habits. It is smaller than ichthyopterygians and had unusually large flippers that probably allowed limited terrestrial locomotion. It also retained characteristics of terrestrial diapsid reptiles, including a short snout and body trunk. Unlike more-derived ichthyosauriforms, it was probably a suction feeder. The new species supports the sister-group relationships between ichthyosauriforms and Hupehsuchia, the two forming the Ichthyosauromorpha. Basal ichthyosauromorphs are known exclusively from south China, suggesting that the clade originated in the region, which formed a warm and humid tropical archipelago in the Early Triassic. The oldest unequivocal record of a sauropterygian is also from the same stratigraphic unit of the region.

Locomotor performance of three sympatric species of sea kraits (Laticauda spp.) from Orchid Island, Taiwan

Abstract Background Assuming that locomotion has a strong influence on animals’ fitness, we hypothesized that better locomotor performance would be associated with the most frequently utilized habitat. Laticauda colubrina, Laticauda laticaudata, and Laticauda semifasciata have different amphibious habits and microhabitat preferences at Orchid Island, Taiwan. We investigated the morphology and locomotor performance of the three sympatric species of sea krait. The measurements of body size, tail area, and body shape were compared in our study. Data on crawling and swimming speeds were gathered to investigate locomotor performance in terrestrial and aquatic environments. Results We found significant differences in the locomotor performances among the three species. L. colubrina was the most terrestrial species in habits and sprinted significantly faster than the others during terrestrial locomotion. On the other hand, L. semifasciata was the most aquatic species, and it swam significantly faster than the other two species. These results are consistent with our hypothesis that sea kraits move well in their respective primary environments. With respect to the highly aquatic L. semifasciata, its laterally compressed body form, large body size, and large area of compressed tail are considered to be beneficial to swimming in an aquatic environment. Conclusions More data are required to understand the superior terrestrial locomotion of L. colubrina, but this species may benefit from its more-cylindrical body form compared to L. semifasciata and from its greater muscle mass compared to L. laticaudata. L. laticaudata was intermediate in habits but exhibited the poorest performance in both swimming and terrestrial locomotion. The reasons for this remain unclear.

Mammalia, Rodentia, Sigmodontinae, Holochilus brasiliensis (Desmarest, 1819): distribution extention

We report the southernmost record for the marsh rats Holochilus brasiliensis 20 km S of Pedro Luro on Hwy 3, province of Buenos Aires, Argentina (39°41’31.13”S, 62°40’23.5”W) extending the range of the species ca. 110 km S. This represents the first contemporaneous record of H. brasiliensis in Patagonia, and also the only species of sigmodontine rodent with amphibious habits reported in Patagonia.

The cranial anatomy of Metarhinus (Mammalia, Perissodactyla, Brontotheriidae)

ABSTRACT An extraordinarily well-preserved skull of the Uintan brontothere genus Metarhinus, supplemented by a second, less complete specimen, permits a detailed description of the cranial anatomy, including aspects that have never before been described. Of particular interest is the structure of the nasal cavity and internal nares, which may be virtually unique among mammals. The normal air passageway, connecting the nasal cavity to the internal nares, is effectively blocked except for tiny apertures and the functional air passageway re-directed over the top of the vomer, which, itself, has an unusual morphology. The functional significance of so unusual a feature is uncertain, but may have to do with the supposed amphibious habits of this genus, or perhaps, was an adaptation enhancing olfaction. The brain of Metarhinus is found to be typical of early brontotheres, being of small size and consisting of a rectilinear succession of parts: forebrain, midbrain, and hindbrain. The cerebrum is small in size and the cerebellum proportionately large.

Influence of morphology and amphibious life‐style on the feeding ecology of the mudskipper Periophthalmus argentilineatus

The potential feeding advantages that are offered to the barred mudskipper Periophthalmus argentilineatus by its amphibious life‐style were investigated. To this end the feeding ecology of these fish, the position they occupy in the mangrove food web and the importance of different morphological factors for their diet were studied. Analysis of gut contents showed that the major component of the barred mudskipper diet changes during growth from small crustaceans (e.g. copepods and amphipods) to polychaetes to mangrove crabs. This dietary shift was found to be facilitated through enlargement of the mouth, as well as elongation of the gut. The use of stable isotope analysis revealed that barred mudskippers had a similar trophic position as other zoobenthivore fish species, but that their diet did not appear to be affected by competition for food with other zoobenthivores. The amphibious habits of the barred mudskipper provide specific advantages to its feeding ecology, such as access to an abundant food source of mangrove crabs, which are mostly inaccessible for other fish species.

ANATOMICAL REVISION OF THE GENUSMERYCOPOTAMUS(ARTIODACTYLA; ANTHRACOTHERIIDAE): ITS SIGNIFICANCE FOR LATE MIOCENE MAMMAL DISPERSAL IN ASIA

Abstract: New fossil remains of the anthracothere genusMerycopotamusFalconer and Cautley, are described. Most of them were discovered by the Harvard University and Geological Survey of Pakistan joint research project (Y‐GSP) in the well‐dated Middle and Late Miocene deposits of the Potwar Plateau in northern Pakistan. This new material led us to revise the systematics of the genus with the validation of three species,M. nanusFalconer (M. pusillusLydekker),M. dissimilisFalconer and Cautley, andM. medioximusLihoreauet al., and allowed us to determine precisely their chronological distributions in a continuous Neogene sequence. Other specimens reported from the late Miocene deposits of the Khorat Plateau in north‐east Thailand by the Department of Mineral Resources are the first remains ofMerycopotamusto have been discovered in that region and are attributed toM. medioximus. These discoveries indicate a wider geographical distribution of the genus in the early Late Miocene. Anatomical investigations highlight the evolution ofMerycopotamusthrough the Miocene towards more amphibious habits. Palaeobiogeographical and palaeoecological information forMerycopotamusstress the role of the Himalayan orogenesis as a dispersal barrier and the impact of a major global regression event on the evolution of Indian Subcontinent faunas from the Middle Miocene to the Late Pliocene.

Adaptations of amphibious fish for surviving life out of water

AbstractThere are a small number of fish species, both marine and freshwater, that exhibit a truly amphibious habit that includes periods of aerial exposure. The duration of emersion is reflected in the level of physical and physiological adaptation to an amphibious lifestyle. Fish that are only briefly out of water retain predominantly aquatic attributes whereas there are semi‐terrestrial species that are highly adapted to prolonged periods in the aerial habitat. Desiccation is the main stressor for amphibious fish and it cannot be prevented by physiological means. Instead, amphibious fish resist excessive water loss by means of cutaneous modification and behavioural response. The more terrestrially adapted fish species can tolerate considerable water loss and may employ evaporation to aid thermoregulation. The amphibious habit is limited to fish species that can respire aerially. Aerial respiration is usually achieved through modification to existing aquatic pathways. Freshwater air‐breathers may respire via the skin or gills but some also have specialized branchial diverticula. Marine species utilize a range of adaptations that may include modified gills, specialized buccopharyngeal epithelia, the intestine and the skin. Areas of enhanced respiratory activity are typified by increased vascularization that permits enhanced perfusion during aerial exposure. As with other adaptations the mode of nitrogenous elimination is related to the typical durations of emersion experienced by the fish. Intertidal species exposed on a regular cycle, and which may retain some contact with water, tend to remain ammoniotelic while reducing excretion rates in order to prevent excessive water loss. Amphibious fish that inhabit environments where emersion is less predictable than the intertidal, can store nitrogen during the state of emersion with some conversion to ureotelism or have been shown to tolerate high ammonia levels in the blood. Finally, the more amphibious fish are more adapted to moving on land and seeing in air. Structural modifications to the pectoral, pelvic, dorsal and anal fins, combined with a well‐developed musculature permit effective support and movement on land. For vision in air, there is a general trend for fish to possess close‐set, moveable, protruberant eyes set high on the head with various physical adaptations to the structure of the eye to allow for accurate vision in both air and water.

Macrófitas aquáticas da lagoa de Jijoca de Jericoacoara, Ceará, Brasil

A lagoa de Jijoca de Jericoacoara situa-se no litoral do Ceará, Nordeste do Brasil (2º50'10'' e 2º55'32''S - 40º28'32'' e 40º24'09''W), sendo bordejada em sua extremidade Norte por dunas e por vegetação de tabuleiro nas demais faces. Realizou-se o levantamento da composição florística e da estrutura da comunidade de macrófitas aquáticas presentes na lagoa. As amostras das plantas foram coletadas e depositadas no herbário EAC. Densidade, freqüência e cobertura das espécies foram amostradas em 10 transectos plotados em áreas com boas condições de conservação de suas margens, evitando-se áreas urbanas e de atividade agropecuária adjuntas à lagoa. Apresenta-se a lista de 45 espécies ocorrentes, suas formas biológicas e dados da estrutura da comunidade. As espécies com maior índice do valor de importância (IVI) foram Eleocharis mutata (L.) Roem. & Schult., Paspalidium geminatum Stapf, Eleocharis atropurpurea (Retz.) Kunth, Nymphoides indica (L.) Kuntze e Echinodorus tenellus (Mart.) Buchen. A forma de vida predominante foi "plantas enraizadas ao substrato - anfíbias tolerantes à seca". Em relação à profundidade, ocorre aumento da diversidade de espécies de áreas mais profundas para 0-0,5m de espessura da lâmina d'água.

Distribution and habitats of the snail Lymnaea truncatula, intermediate host of the liver fluke Fasciola hepatica, in South Africa.

This paper focuses on the geographical distribution and habitats of Lymnaea truncatula, the intermediate, snail host of the liver fluke, Fasciola hepatica, as reflected by the 723 samples in the database of the National Freshwater Snail Collection, Potchefstroom, South Africa. The 221 different loci (1/16-degree squares) on record reflect an extensive but discontinuous distribution, except in Lesotho and in parts of the Mpumalanga, Gauteng and North West provinces of South Africa. Although recorded from 12 different types of waterbody, it was mostly (42.0%) recovered from swamps. Most samples (45.8%) were collected in habitats with slow-flowing water. A muddy substratum was recorded for 62.5% of the samples. Most samples (86.3%) were collected in habitats with a mean annual air temperature of 10-20 degrees C, and more than 69% came from localities with a mean annual rainfall of 600-900 mm. An integrated decision tree constructed from the data indicated that temperature and types of waterbody play a decisive role in determining the presence of L. truncatula in a given area. A temperature index calculated for all mollusc species ranked L. truncatula second in a total of 53 species according to its association with low temperatures. It remains to be established whether its distribution is indeed discontinuous, and whether its preference for a particular habitat, amphibious habits and ability to aestivate could have resulted in some populations having been overlooked during surveys.

Lanceispora amphibia gen. et sp. nov., a new amphisphaeriaceous ascomycete inhabiting senescent and fallen leaves of mangrove

Lanceispora amphibia gen. et sp. nov. in the Amphisphaeriaceae is described from senescent and fallen leaves ofBruguiera gymnorrhiza in mangrove forests in the Southwest Islands, Japan. The fungus produces immersed ascomata in leaf tissue, cylindrical asci with an apical ring staining blue with iodine, and oblanceolate ascospores with a septum above the middle. Studies on the fungal succession on the mangrove leaves revealed thatL. amphibia infects senescent leaves on the tree and inhabits intertidal fallen leaves, showing the highest frequency of occurrence at the late stage of decomposition. In culture the optimal conditions for hyphal growth were 20 ppt salinity and 30°C, and those for sexual reproduction were 10 ppt salinity and 25°C. Growth at 0 ppt (fresh water) was depressed. The fungus has amphibious habits, growing on the tree and in intertidal water; and it is adapted to the high osmotic conditions in leaf tissues of the mangrove tree and to the subtropical, brackish water environment of mangrove forests.