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Schweizer, M., Guntert, M. & Hertwig, S. T. (2012). Out of the Bassian province: historical biogeography of the Australasian platycercine parrots (Aves, Psittaciformes). —Zoologica Scripta, 42, 13–27. Aridification from mid-Miocene onwards led to a fragmentation of mesic biomes in Australia and an expansion of arid habitats. This influenced the diversification of terrestrial organisms, and the general direction of their radiations is supposed to have been from mesic into drier habitats. We tested this hypothesis in the platycercine parrots that occur in different habitats in Australia and also colonized Pacific islands. We inferred their temporal and spatial diversification patterns using a Bayesian relaxed molecular clock approach based on three nuclear and two mitochondrial genes and model-based biogeographic reconstructions. The Bassian biota was found to be the centre of origin of platycercine parrots and diversification within two of their three clades coincided with the beginning of aridification of Australia. The associated habitat changes may have catalysed their radiation through adaptation to arid environments and vicariance because of the fragmentation of non-arid habitats. The small oceanic islands of Melanesia contributed as stepping stones for the colonization of New Zealand from Australia.

Hertwig, S.T., Das, I., Schweizer, M., Brown, R., & Haas, A. (2012). Phylogenetic relationships of the Rhacophorus everetti-group and implications for the evolution of reproductive modes in Philautus (Amphibia: Anura: Rhacophoridae). —Zoologica Scripta, 41, 29–46. This study presents the first phylogenetic analysis of the enigmatic Rhacophorus everetti species group and the first description of its unique tadpole. A total sample of 95 12S and 16S mitochondrial rDNA sequences were compiled including new sequence data from 28 rhacophorid species. Based on 1332 and 1407 bp, respectively, and on the gap coding method applied, a new hypothesis about the phylogeny of rhacophorid tree frogs from Sundaland was obtained. While Rhacophorus was uncovered as a polyphyletic assemblage, the monophyly of the Bush Frogs of the genus Philautus, including the Rhacophorus everettigroup, is robustly supported. We, therefore, transfer the everetti-group to the genus Philautus. As a second step, we recognise Philautus macroscelis (comb. nov.) from Borneo and P. everetti (comb. nov.) from Palawan as distinct allopatric species. Molecular and morphological evidence clearly indicates that each is a distinct lineage with a unique ancestry and discrete evolutionary fate. Moreover, close phylogenetic relationships of several Philautus species from Borneo to taxa from outside Borneo were recovered; P. everetti and P. macroscelis being the only one example. These findings indicate a complex biogeographical history of Sundaland Bush Frogs, which can only be explained by repeated dispersal and vicariance events between the Asian mainland and the Sunda islands. Finally, a single tadpole discovered on Gunung Kinabalu was matched genetically to P. macroscelis. Features of its peculiar external morphology suggest that this larva is endotrophic and possibly nidicolous. A comparable reproductive biology was formerly unknown in rhacophorid tree frogs. The presence of a free-swimming tadpole in Philautus challenges the notion that terrestrial direct development represents an apomorphic character unambiguously shared by all members of this genus. The implications for the evolution of reproductive modes in Bush Frogs are discussed in a phylogenetic context.

Aim Parrots are thought to have originated on Gondwana during the Cretaceous. The initial split within crown group parrots separated the New Zealand taxa from the remaining extant species and was considered to coincide with the separation of New Zealand from Gondwana 82-85 Ma, assuming that the diversification of parrots was mainly shaped by vicariance. However, the distribution patterns of several extant parrot groups cannot be explained without invoking transoceanic dispersal, challenging this assumption. Here, we present a temporal and spatial framework for the diversification of parrots using external avian fossils as calibration points in order to evaluate the relative importance of the influences of past climate change, plate tectonics and ecological opportunity. Location Australasian, African, Indo-Malayan and Neotropical regions. Methods Phylogenetic relationships were investigated using partial sequences of the nuclear genes c-mos, RAG-1 and Zenk of 75 parrot and 21 other avian taxa. Divergence dates and confidence intervals were estimated using a Bayesian relaxed molecular clock approach. Biogeographic patterns were evaluated taking temporal connectivity between areas into account. We tested whether diversification remained constant over time and if some parrot groups were more species-rich than expected given their age. Results Crown group diversification of parrots started only about 58 Ma, in the Palaeogene, significantly later than previously thought. The Australasian lories and possibly also the Neotropical Arini were found to be unexpectedly species-rich. Diversification rates probably increased around the Eocene/Oligocene boundary and in the middle Miocene, during two periods of major global climatic aberrations characterized by global cooling. Main conclusions The diversification of parrots was shaped by climatic and geological events as well as by key innovations. Initial vicariance events caused by continental break-up were followed by transoceanic dispersal and local radiations. Habitat shifts caused by climate change and mountain orogenesis may have acted as a catalyst to the diversification by providing new ecological opportunities and challenges as well as by causing isolation as a result of habitat fragmentation. The lories constitute the only highly nectarivorous parrot clade, and their diet shift, associated with morphological innovation, may have acted as an evolutionary key innovation, allowing them to explore underutilized niches and promoting their diversification.

The present study reports the discovery of the hitherto unknown breeding grounds of the large-billed reed warbler Acrocephalus orinus in the Badakhshan region of Tajikistan. A total of eight adult individuals were caught at three riverine woodland sites and breeding was confirmed at one locality. The identity of the birds was confirmed on the basis of partial sequences of the cytochrome b gene. Even among individuals sampled at the same locality, genetic diversity was surprisingly high. This was interpreted as the result of secondary contact between previously isolated or fragmented populations. The breeding range of the large-billed reed warbler is likely small and the species’ habitat is under intense pressure from the collection of firewood and fodder. Consequently, the large-billed reed warbler remains of considerable conservation concern.

The medaka, Oryzias latipes, is a model organism in experimental biology. Its ontogeny and osteology have been studied frequently, but no detailed description of its cranial anatomy exists. Based on manual dissections, histological slide sections, and 3D-reconstructions, we describe the anatomy of the jaw apparatus of O. latipes, focusing on musculature, connective tissue elements, and the nervous system. The soft tissue anatomy of the head of O. latipes is characterized by several derived characters that seem to be related to the modification of the upper jaw and a reduced mobility of its bones, which is an evolutionary novelty of the Beloniformes. These apomorphies could also be influenced by the small size of O. latipes. The maxilla is medial to the premaxilla. The presence of extensive connective tissue elements severely limits the mobility of both bones against each other and against the neurocranium. The external section of m. adductor mandibulae is partly fused with the internal section, originates from the quadrate, and inserts to the lower jaw. The intermediate head of the internal section is narrow and forms a bend along the ventral margin of the orbit. The intramandibular section is a separate narrow muscle between retroarcticular and dentary. These characters need to be verified in other representatives of Beloniformes to test their contribution to the disputed phylogenetic relationships within this taxon and to improve the understanding of the evolution of beak-like jaws in beloniform fishes.

This study presents a cladistic analysis of the Cyprinodontiformes based on a comparative anatomical examination of 95 species. Seventy-eight characters of musculature, connective tissue elements and nervous system of the jaw apparatus are described, in many cases for the first time. In order to investigate the contribution of such soft tissue traits, the new data have been analysed separately and in combination with an extensive data matrix of morphological, primarily osteological characters produced by Costa using the nona software. The inclusion of soft tissue characters led to the description of numerous additional apomorphies and to an improved resolution of the consensus topologies in the combined analysis. Though the consensus of the separate tree searches was limited in resolution due to a relatively high degree of homoplasy and probably to rapidly evolving adaptive transformations, phylogenetic hypotheses mostly congruent to recent phylogenetic studies were yielded. These findings are evidence for the usability of cranial soft tissue characters as a reliable additional source of information for cladistic studies of fish phylogeny. With regard to the highly contentious deep splitting events within the Cyprinodontiformes and the monophyly of the Aplocheilidae, the consideration of the new data supported a new hypothesis that agrees with the palaeogeographical framework of the break-up of Gondwana. The genus Aplocheilus from India represents the sister group to all remaining taxa of the Cyprinodontiformes, while the second branch separates the genus Pachypanchax from Madagascar. A comparable biogeographical pattern has been found congruently in different groups of teleostean freshwater fishes. The Valenciidae from Europe are closely related to the Nearctic taxon Funduloidea. The placement of the genus Fluviphylax remained unresolved because it is not only characterized by the possession of several derived characters but also by numerous plesiomorphic ones.

Aim The Neotropical parrots (Arini) are an unusually diverse group which colonized South America in the Oligocene. The newly invaded Neotropics may have functioned as an underused adaptive zone and provided novel ecological opportunities that facilitated diversification. Alternatively, diversification may have been driven by ecological changes caused by Andean uplift and/or climate change from the Miocene onwards. Our aim was to find out whether Arini diversified in a classical adaptive radiation after their colonization of South America, or whether their diversification occurred later and was influenced by more recent environmental change. Location Neotropics. Methods We generated a time-calibrated phylogeny of more than 80% of all Arini species in order to analyse lineage diversification. This chronogram was also used as the basis for the reconstruction of morphological evolution within Arini using a multivariate ratio analysis of three size measurements. Results We found a concentration of size evolution and partitioning of size niches in the early history of Arini consistent with the process of adaptive radia- tion, but there were no signs of an early burst of speciation or a decrease in speci- ation rates through time. Although we detected no overall temporal shifts in diversification rates, we discovered two young, unexpectedly species-rich clades. Main conclusions Arini show signs of an early adaptive radiation, but we found no evidence of the slowdown in speciation rate generally considered a feature of island or lake radiations. Historical processes and environmental change from the Miocene onwards may have kept diversification rates roughly constant ever since the colonization of the Neotropics. Thus, Arini may not yet have reached equilibrium diversity. The lack of diversity-dependent speciation might be a general feature of adaptive radiations on a continental scale, and diversification processes on continents might therefore not be as ecologically limited as in isolated lakes or on oceanic islands.