Morphological and Genetic Recovery of Coral Polyps After Bail-Out

Contemporary advances in microfluidic and molecular techniques have enabled coral studies to shift from reef and colony scales to polyp- and molecular-level investigations. Polyp bail-out provides an alternative approach to acquire solitary polyps for studies at finer scales. Although induction of polyp bail-out has been reported in several studies, polyp health after bail-out has not been investigated. In this study, we monitored morphological and genetic changes in Pocillopora acuta polyps after bail-out induced by hyperosmosis. In isosmotic conditions, over 80% of bailed-out polyps survived, of which half regenerated normal polyp morphology within 5 days, including a polarized polyp body, extended tentacles, and a distinguishable oral disk. In contrast, the remaining polyps degenerated into tissue ball-like structures that resemble multicellular aggregates reported in earlier studies. In morphologically recovered polyps, transcriptomic analysis showed that ∼87% of genes altered during bail-out induction recovered from stress status, suggesting resumption of metabolism, cell division, and immunity, while in degenerated polyps, only ∼71% of genes recovered. Quantitative polymerase chain reaction data further demonstrated that genetic recovery of energy production, cell proliferation, and immune response was achieved in morphologically recovered polyps within 3 days after bail-out, but was not fully accomplished in degenerated polyps even after 5 days. Our findings indicate that solitary polyps generated by hyperosmosis-induced bail-out can recover rapidly from physiological stress under laboratory conditions, suggesting that bailed-out polyps could be used as new models for coral research.

Tadpole morphology of the white-eyed toad Leptobrachium leucops Stuart, Rowley, Tran, Le & Hoang 2011 (Anura: Megophryidae) in Bidoup – Nui Ba National Park, Lam Dong province

We describe the tadpole morphology of the white-eyed megophryd, Leptobrachium leucops Stuart, Rowley, Tran, Le & Hoang 2011 based on specimens originating from Bidoup – Nui Ba National Park, Lam Dong Province, Vietnam. The description is based on larva in developmental stages 25 - 41, which were bred at the University of Science, Vietnam National University-Ho Chi Minh City. Tadpoles of Leptobrachium leucops live in slow-flowing water - benthic with the body color from brown-black to black. Body oval shape in lateral view, dorsolaterally positioned eyes. Spiracle sinistral and leftlateral positioned. Vent tube medially located at body end, ventrally positioned. Oral disk ventrally positioned and bordered by a papillae row, in general, the keratodont row formulae of the is 1(5+5)/(4+4)1. Body length and oral disk width increase during developmental stages while tooth density decreases gradually and disappeare at the stage of 41.

Diversity, external morphology and ‘reverse taxonomy’ in the specialized tadpoles of Malagasy river bank frogs of the subgenus Ochthomantis (genus Mantidactylus)

We provide detailed morphological descriptions of the tadpoles of Malagasy river bank frogs of the subgenera Ochthomantis and Maitsomantis (genus Mantidactylus, family Mantellidae), and data on relative abundance and habitat preferences of Ochthomantis species from Ranomafana National Park in southeastern Madagascar. Our study includes the tadpoles of six described and four undescribed candidate species. Eight of these larvae were previously unknown. Tadpoles were identified by DNA barcoding. Due to the very rudimentary taxonomic knowledge on Ochthomantis, we followed a ‘reverse taxonomy’ approach in which adult classification was to a great part determined on the basis of larval differences. By this procedure we even identified one candidate species whose adults remain still unknown. The majority of tadpoles in Ochthomantis and Maitsomantis have a rather similar body shape and they usually have similar habitat requirements. However, on the basis of the structure of their oral disk we identified three distinct groups: the first includes the femoralis-like tadpoles of Mantidactylus femoralis, M. ambreensis, M. zolitschka, M. argenteus, and of the candidate species named M. sp. 42, M. sp. 43 and M. sp. 47. They all have a reduced oral disk with poorly keratinized jaw sheaths and labial teeth. The mocquardi-like tadpoles of M. mocquardi and M. sp. 64 are placed in the second group and are characterized by a further reduction of oral disk structures, i.e. a complete lack of labial teeth. The third group includes only M. majori and is characterized by the transformation of the upper jaw sheath into three thorn-shaped projections. Based on a preliminary molecular phylogenetic analysis the reduction of keratinized oral structures in M. majori may have occurred convergently to that in M. mocquardi. The ecological data indicate that the tadpoles of the three most abundant species in Ranomafana (M. femoralis, M. majori and M. sp. 47) do not obviously differ in their choice of microhabitat although the differences in their oral structures indicate that they might use different food resources. They all show a preference for the stream areas with slow current and leaf litter substrate.

Isozoanthus antumbrosus, a new species of zoanthid (Cnidaria: Anthozoa: Zoanthidea) symbiotic with Hydrozoa from the Caribbean, with a key to hydroid and sponge-symbiotic zoanthid species

Isozoanthus antumbrosus, a new species of zooxanthellate zoanthid, is described. Colonies associate with the arborescent hydroid Dentitheca dendritica in the Caribbean Sea at 1–60 m. The coenenchyme, column, and oral disk are seal brown. The tentacles are golden brown and number 30–38. The coloration of the oral disk and tentacles recalls an annular solar eclipse. Polyps are 4.1–8.9 mm long and 2.2–4.3 mm in diameter. Genetic, morphological, and ecological characters differentiate this species from other hydroid-symbiotic zoanthids. Assignment to the genus Isozoanthus is based on morphology, with the acknowledgment that the currently accepted genera may not reflect evolutionary relationships.

Descriptions of the tadpoles of seven species of Malagasy treefrogs, genus Boophis

The genus Boophis is a species-rich group of treefrogs within the family Mantellidae Laurent, endemic to Madagascar. The larval morphology of these frogs is an important trait to understand the evolution of reproductive modes and larval morphologies in the mantellid radiation and can provide important information to compare adaptations of tadpoles and adults, and elucidate possible covariation, and convergent evolution of these traits. We here assign seven previously unknown or insufficiently described Boophis tadpoles to species via DNA barcoding, and provide detailed morphological descriptions based mainly on the unambiguously identified DNA voucher specimens. All described tadpoles are stream-adapted, exotrophic tadpoles of a relatively generalized morphology. Applying our previous classification for stream-breeding Boophis based on relative oral disk width and the number of papillae and keratodonts we attempt an assignment of all species into ecomorphological guilds. Our results show that this previous definition of guilds (in Boophis) based on only three characters was an oversimplification, and that the variation in these tadpoles is more complex. In a phylogenetic context we found that species within at least two species groups of Boophis are heterogeneous in their assignment to the ecomorphological guilds confirming the probable non-monophyly of these groups.

Description of a new Lithoxus (Siluriformes: Loricariidae) from the Guayana Highlands with a discussion of Guiana Shield biogeography

Lithoxus jantjae, new species, is described from above Tencua Falls in headwaters of the Ventuari River, a white- to clearwater river flowing west from the Maigualida and Parima mountains in the Guayana Highlands of southern Venezuela. Lithoxus jantjae represents a nearly 600 km westward range expansion for a genus historically known only from Guyana, Suriname, French Guiana, and Brazil. Lithoxus jantjae shares with other species of Lithoxus a dorsoventrally depressed body and a large, papilose oral disk with small toothcups and few teeth. It can be distinguished from congeners by a unique combination of characters including 12 branched caudal-fin rays, medial premaxillary tooth cusps enlarged, and a convex posterior margin of the adipose-fin membrane. With the discovery of L. jantjae, Lithoxus becomes the most recent example of a growing list of rheophilic loricariid genera with disjunct distributions on east and west sides of the Guayana Highlands. A biogeographic hypothesis relying on the existence of a proto-Berbice River uniting the southern Guayana Highlands with rivers of the central Guiana Shield is advanced to partially explain the modern distribution of these species.

Description of the tadpole of Leptodactylus vastus (Anura: Leptodactylidae)

The Neotropical frog Leptodactylus vastus belongs to the L. pentadactylus group, a group that currently contains 14 species, and of which nine tadpoles have been described. The tadpoles of L. vastus described here are generally much smaller than tadpoles of the other species described. The oral disk of L. vastus tadpoles is almost anteriorly placed, similar to other tadpoles in the group except for L. lithonaetes and L. rugosus, and the rows of marginal papillae in L. vastus are different from those in the other species. The tadpoles of L. vastus have a 1/2(1) LTRF similar to that of L. labyrinthicus and amazonian L. pentadactylus, whereas other species in the group show different arrangements of the tooth rows. The internal oral characteristics of the tadpole of L. vastus differs from L. knudseni and L. pentadactylus by having four infralabial papillae, possess 4–5 prepocket papillae surrounded by postulations and the buccal roof arena is circular, surrounded by two long papillae and 4–6 smaller papillae. The tadpoles of L. vastus, in general, possess a set of morphological characteristics that are very similar to those of other species of the L. pentadactylus group, and some of them are probably related to tadpole ecology.

Description of the tadpole of Itapotihyla langsdorffii (Anura: Hylidae)

The tadpole of Itapotihyla langsdorffii is described and illustrated. Morphological data are compared with available information on tadpoles of casque-headed frogs occurring in the Atlantic Rainforest (genera Aparasphenodon and Trachycephalus), and also with Osteocephalus. The ontogenetic shift in tooth row formula and the great similarity on tadpole external morphology among these genera do not allow the use of the examined larval characters on generic diagnoses. However, we present some juvenile characters which may support the validity of Itapotihyla. The confrontation of the hypotheses concerning oral disk morphology and larval habitat types of the casque-headed tree frogs with the phylogeny of the Lophiohylini indicates that the ancestral larval habitat of this tribe was lentic and that the high number of tooth rows in this clade is not related to larval habitat.