Oviposition and development in the glass frog Hyalinobatrachium orientale (Anura: Centrolenidae)

Oviposition and development in the glass frog Hyalinobatrachium orientale (Anura: Centrolenidae). Oviposition and external embryonic developmental features are described in the Tobago glass frog, Hyalinobatrachium orientale. Egg clutches are nearly always laid on the undersides of leaves (one exception); usually leaves of Heliconia sp. are used, but Philodendron and palms may be used in the absence of Heliconia. Clutches contain 28.0 ± 5.3 eggs (mean ± SD) and eggs are 1.86 ± 0.11 mm in diameter. The behavior of one amplectant pair was followed for more than five hours; the pair rotated several times around a small area of the leaf depositing eggs in a tight spiral formation. External embryonic features were observed by scanning electron microscopy. Surface ciliation is extensive up to the time of hatching when it is lost; external gills are short and a cement gland is absent. Hatching gland cells were detectable on the anterodorsal surface of the head from Day 4 after deposition and persisted until at least Day 10, and hatching occurred between Days 9 and 16. During this period, progressive development in tail length, surface pigmentation, intestinal coiling, and oral disc features was observed. Post-hatching larvae reared for six weeks grew 37% in length and tripled in weight, but remained at Gosner Stage 25

Natural history contributions of the University of Glasgow Exploration Society to Scotland and the World

Expeditions with a natural history focus have been organised by University of Glasgow staff and students since the 1930s. The educational benefits of such expeditions to students have been reported by Harper et al. ( Journal of Biological Education 51, 3- 16; 2017). Here, we present a short history of these expeditions, concentrating on their scientific achievements. In addition to expedition reports, a large number of PhD theses, masters and honours project reports and scientific papers have been based on expedition work. Many biological specimens have been deposited in museums, including some new species. We provide case histories of four expedition locations, to demonstrate the variety of work done, and the value of returning many times to the same place: Scotland, Trinidad and Tobago, North Cyprus and Ecuador. A major problem for expeditions is funding. For many years, the Carnegie Trust for the Universities of Scotland ran a funding stream that was crucial to the viability of Scottish university expeditions, but this has sadly now closed. For Glasgow University expeditions, the Blodwen Lloyd Binns Bequest has provided a reliable source since 1994, and we hope that it will continue to do so

Evaluation of tree frog tracking methods using Phyllomedusa trinitatis (Anura: Phyllomedusidae)

Evaluation of tree frog tracking methods using Phyllomedusa trinitatis (Anura: Phyllomedusidae). Investigating the behaviors of small, inconspicuous and cryptic animals can be helped by tracking their movements. The effectiveness of different tracking methods can be very dependent on behavior and ecology; radio-telemetry and thread bobbins have been widely used over a range of environments and taxa, but each presents problems. Phyllomedusa trinitatis is a tree frog found in Trinidad and Venezuela and has mostly been studied for its nest building and breeding behavior, but little is known about its behavior away from breeding ponds. This study aimed to identify the strengths and weaknesses, including impacts on the welfare of these frogs, of different tracking methods, thread bobbins and radio-telemetry, when used to track them in a dense rainforest environment. A pilot study found that fuorescent dyes were unsuitable for this species. Individuals were tested in laboratory conditions to determine the application time for each tracker and to test on this species the tracker 10% weight rule. The rule was found to be too restrictive for this frog; trackers up to 15% of body weight were used with no signifcant impacts on distances travelled. Frogs became lethargic when bearing trackers longer than two days, so we limited tracking in the feld to one overnight period. Of the 26 frogs tracked in the feld (nine radio-tags, 17 bobbins), 16 were successful (six radio-tags, 10 bobbins) and six untracked frogs were found in the feld during the day as controls. Bobbins were cheaper and allowed visualization of the detailed path taken, including substrates used, but caused more bruising due to entanglement, and individuals tracked with this method were less likely to return on following nights to the breeding ponds. Radio-tags had no threat of entanglement but were much more expensive and the signal was interrupted by the dense vegetation preventing some individuals from being found. There were no signifcant differences in the distances travelled by tracked or control frogs, from which we infer that these tracking methods did not impact signifcantly on movement. It appears that neither of these tracking methods work perfectly for Phyllomedusa in a densely vegetated environment, and that both incur welfare problems. Our study emphasizes the need to test out tracking methods on each species in each habitat.Avaliação de métodos de rastreamento de pererecas usando Phyllomedusa trinitatis (Anura: Phyllomedusidae). A investigação do comportamento de animais pequenos, inconspícuos e crípticos pode ser auxiliada pelo rastreamento de seus movimentos. A efciência de diferentes métodos de rastreamento pode ser muito dependente de seu comportamento e ecologia; rádiotelemetria e bobinas de rastreamento têm sido largamente utilizadas com uma variedade de ambientes e táxons, mas cada uma dessas técnicas apresenta problemas. Phyllomedusa trinitatis é uma perereca encontrada em Trinidad e na Venezuela e tem sido estudada principalmente no que se refere a seu comportamento reprodutivo e de construção de ninhos, mas pouco se sabe sobre seu comportamento longe das lagoas reprodutivas. Este estudo teve como objetivo identifcar vantagens e desvantagens de diferentes métodos de rastreamento (bobinas de rastreamento e rádio-telemetria), incluindo impactos no bem-estar desses anuros, quando usados para rastreá-los em um ambiente de foresta pluvial densa. Um estudo-piloto mostrou de tintas fuorescentes foram inadequadas para essa espécie. Indivíduos werforam testados em condições laboratoriais para determinar o tempo de aplicação de cada rastreador e para testar nessa espécie a regra dos 10% do peso. A regra mostrou-se muito restritiva para essa perereca; rastreadores com até 15% do peso corpóreo foram usados sem impactos signifcativos sobre a distância percorrida. Os animais tornaram-se letárgicos quando portavam rastreadores por mais de dois dias, de forma que limitamos o rastreamento no campo a um período de uma noite. Dos 26 indivíduos rastreados no campo (nove com radiotransmissores, 17 com bobinas), 16 foram bem-sucedidos (seis com radiotransmissores, 10 com bobinas) e seis indivíduos não-rastreados foram encontrados no campo durante o dia como controles. As bobinas são mais baratas e permitem a visualização detalhada do caminho percorrido, incluindo os substratos utilizados, mas causam mais injúrias devido ao entrelaçamento, e os indivíduos rastreados com este método eram menos propensos a retornar nas noites seguintes para as lagoas de reprodução. Os radiotransmissores não ofereciam a ameaça de emaranhamento, mas são muito mais caros, e o sinal era interrompido pela densa vegetação, impedindo que alguns indivíduos fossem encontrados. Não houve diferenças signifcativas nas distâncias percorridas por indivíduos rastreados e animaiscontrole, do que inferimos que esses métodos de rastreamento não tiveram impacto signifcativo sobre o movimento. Parece que nenhum desses métodos de rastreamento funciona perfeitamente para Phyllomedusa em um ambiente com vegetação densa e que ambos geram problemas de bem-estar. Nosso estudo enfatiza a necessidade de testar métodos de rastreamento para cada espécie em cada habitat

Observations on metamorphosing tadpoles of Hyalinobatrachium orientale (Anura: Centrolenidae)

Observações sobre girinos de Hyalinobatrachium orientale (Anura: Centrolenidae) em metamorfose. A metamorfose, processo em que os anfíbios anuros reabsorvem suas caudas e remodelam suas partes bucais e órgãos internos, é um estágio vulnerável de sua história de vida. Durante a transformação de larvas em adultos, os girinos não estão bem adaptados à vida aquática nem à vida terrestre ativa. Estudos anteriores examinaram a duração da metamorfose em diversas espécies com relação ao tamanho do girino, habitat e outros fatores; entretanto, a duração da metamorfose em relação ao local onde esta ocorre não foi relatada pantrolenídeos. Em Hyalinobatrachium orientale, a metamorfose ocorre nas superfícies superiores das folhas das plantas de sub-bosque baixo e dura de 3,5 a 4,0 dias, um pouco mais do que o esperado para um girino desse tamanho de corpo. Os indivíduos recém-metamorfoseados parecem mudar seus poleiros de folha para folha aleatoriamente. Não há diferenças significativas na temperatura ou umidade relativa das superfícies superior e inferior das folhas no sub-bosque da floresta; assim, o uso das superfícies superiores das folhas pode fornecer-lhes umidade da vegetação do estrato superior após as chuvas e protegê-los de predadores terrestres.Observations on metamorphosing tadpoles of Hyalinobatrachium orientale (Anura: Centrolenidae). Metamorphosis, when anuran amphibians resorb their tails and remodel their mouthparts and internal organs, is a vulnerable stage in the frog’s life history. As larvae metamorphose from tadpoles to adult frogs, they are neither suited to aquatic life nor ready for active terrestrial life. Previous studies have examined the duration of metamorphosis in a range of species, with respect to tadpole size, habitat, and other factors; however, the duration of metamorphosis relative to where it takes place has not been reported in centrolenids. In Hyalinobatrachium orientale, metamorphosis takes place on the upper surfaces of the leaves of low understory plants and lasts 3.5–4.0 days, a little longer than expected for the tadpole of this body size. Metamorphs seem to shift their perches from leaf to leaf randomly. There are no significant differences in the temperature or relative humidity of the upper and lower surfaces of leaves in the forest understory; thus, the presence of the metamorphs on the upper surfaces of leaves may provide moisture from the upper story vegetation after rain and protect them from terrestrial predators

The behaviour of recently hatched Tobago glass frog tadpoles

Egg clutches of the Tobago glass frog Hyalinobatrachium orientale tobagoense were collected from streams around the north-east of Tobago and hatched into tanks of native stream water. Previously unreported behaviour of newly hatched tadpoles was observed. Observations were made through a series of tests for substrate preference (gravel, rocks or leaves), shelter or open water preference, and surfacing behaviour under different depths and turbulence levels. Tests found that tadpoles showed a preference for stream substrates over plastic tank floor, with the highest percentage of tadpoles found in gravel. Tadpoles preferred sheltered areas of the tank, and surfaced significantly less when water was turbulent, with depth having no significant effect on surfacing behaviour

Stable individual variation in ventral spotting patterns in Phyllomedusa trinitatis (Anura: Phyllomedusidae) and other Phyllomedusa species: a minimally invasive method for recognizing individuals

Variação individual estável no padrão de manchas ventrais em Phyllomedusa trinitatis (Anura: Phyllomedusidae) e em outras espécies de Phyllomedusa: um método minimamente invasivo para o reconhecimento de indivíduos. Descrevemos aqui um padrão distintivo de “ilhas” e pontos brancos individualmente variáveis nas superfícies ventrais das regiões da garganta e do antebraço de machos e fêmeas de Phyllomedusa trinitatis. Crucialmente, a partir de indivíduos criados em cativeiro relatamos que esses padrões são ontogeneticamente estáveis. Usamos esses padrões para reconhecer pererecas individuais em populações de 60 ou mais indivíduos. O exame das superfícies ventrais de outras espécies de Phyllomedusa em espécimes de museus e de relatos publicados sugere que o uso desses padrões fornece um método de reconhecimento minimamente invasivo e geralmente útil nesse gênero. Descobrimos que espécies anteriormente classifcadas como Phyllomedusa, mas agora consideradas pertencentes a diferentes gêneros, não possuem esses padrões.Stable individual variation in ventral spotting patterns in Phyllomedusa trinitatis (Anura: Phyllomedusidae) and other Phyllomedusa species: a minimally invasive method for recognizing individuals. We describe a distinctive pattern of individually variable white ‘islands’ and dots on the ventral surfaces of the throat and forearm regions of male and female Phyllomedusa trinitatis. Crucially, we report from captive-reared individuals that these patterns are ontogenetically stable. We have used these patterns to recognize individual frogs in populations of 60 and more. Examination of the ventral surfaces of other Phyllomedusa species in museum specimens and from published accounts suggests that use of these patterns provides a generally useful, minimally invasive recognition method in this genus. We fnd that species previously classed as Phyllomedusa but now regarded as belonging to different genera lack these patterns

Turning into frogs: asymmetry in forelimb emergence and escape direction in metamorphosing anurans:Lateralised forelimb emergence and turning

There is considerable debate about the pattern and origin of laterality in forelimb emergence and turning behaviour within amphibians, with the latter being poorly investigated in tadpoles around metamorphic climax. Using 6 species of metamorphosing anurans, we investigated the effect of asymmetrical spiracle location, and disturbance at the time of forelimb emergence, on the pattern of forelimb emergence. Turning behaviour was observed to assess whether motor lateralization occurred in non-neobatrachian anurans and was linked to patterns of forelimb emergence. Biases in forelimb emergence differed among species, supporting the hypothesis that asymmetrical spiracle position results in the same asymmetry in forelimb emergence. However, this pattern only occurred when individuals were undisturbed. Therefore, context at the time of the emergence of the forelimbs may be important, and might explain some discrepancies in the literature. Turning biases, unconnected to forelimb emergence, were found in Pipidae and Bombinatoridae, confirming the basal origin of lateralized behaviour among anurans. Turning direction in our metamorphs differed from the leftward bias commonly observed in tadpoles, but may be analogous to the prevalent right-“handedness” among adult anurans. Therefore, the transitions occurring during metamorphosis may affect lateralized behaviour and metamorphosis may be fruitful for understanding the development of lateralization