Osteology and relationships of Thaiichthys nov. gen.: a Ginglymodi from the Late Jurassic – Early Cretaceous of Thailand

Abstract: The osteology of Thaiichthys buddhabutrensis, nov. gen., from the Late Jurassic – Early Cretaceous of Thailand is described on the basis of a collection of well‐preserved specimens. The mode of preservation of the material allows describing the external anatomy, as well as some elements of the internal anatomy (braincase, elements of the vertebral column). Most of the cranial and postcranial skeleton shows a rather conservative anatomy for ‘semionotiformes’, but the jaw apparatus displays specializations. Variations observed in the ossification pattern of the skull roof and of the cheek, in the morphology of the median dorsal scales and in fin rays’ count indicate that caution should be applied when these characters are used in diagnoses and in phylogenetic analyses. A phylogenetic analysis including a set of gars, of ‘semionotiformes’, of Macrosemiiformes and of Halecomorphi shows the following features: (1) the monophyly of Holostei; (2) sister‐pair relationships between Tlayuamichin/Semiolepis, Isanichthys/’Lepidotes’ latifrons and Araripelepidotes/Pliodetes; (3) the latter pair, together with Thaiichthys and possibly ‘Lepidotes’ mantelli, are resolved as stem Lepisosteiformes; and (4) the ‘semionotiformes’ (a group gathering species of Semionotus and Lepidotes) do not form a clade.     

The origin of a ‘true’ worker caste in termites: phylogenetic evidence is not decisive

The phylogenetic study of the origin of a ‘true’ worker caste in termites by Thompson et al. [J. Evol. Biol. 13 (2000) 869] did not take into account all possibilities of character coding and character optimization on the phylogenetic tree. Actually, contrary to the authors' statements, the phylogenetic evidence presented does not permit to answer decisively most of the questions asked concerning the origin and evolution of worker castes in termites. Particular attention was paid to assumptions implied by the coding of the characters of interest, namely concerning the homology between pseudergates and a ‘true’ worker caste and the kind of the cockroach life type.     

Comparative vegetative anatomy and classification of Diseae (Orchidaceae)

The leaf, stem, root, tuber and dropper anatomy of the orchid tribe Diseae (including the subtribes Satyriinae, Disinae, Brownlecinac, Huttonaeinae and Coryciinae) is reviewed. The study is largely based on investigations of 123 species, and data from several previous publications have also been incorporated. Two characters were identified as being taxonomically valuable: (1) the presence of sclerenchyma caps associated with leaf vascular bundles, and (2) the degree of dissection of the siphonostele of the tuber (‘polystelic’ or ‘monostelic’). The phylogenetic analysis shows that anatomical characters do not change the basic structure of a cladogram that is based on morphological characters. The taxa of Diseae are discussed on the basis of anatomical data. Subtribes Satyriinae (excluding the anatomically unusual genus Pachites), Brownleeinae, Huttonaeinae, and Coryciinae are uniform in. critical anatomical characters. However, subtribe Disinae is rather diverse in vegetative anatomy. Disa sect. Micranthae differs from the rest of the genus in its leaf anatomy. The occurrence of foliar sclerenchyma bundle caps and ‘polystelic’ tubers supports the incorporation of Herschelianthe in Disa sect. Stenocarpa.     

Four new species of dwarfgobies (Teleostei: Gobiidae: Eviota) from the Austral,Gambier, Marquesas and Society Archipelagos,French Polynesia

Four new species of Eviota (Teleostei: Gobiidae) are described from French Polynesia. Eviota hinanoae occurs from the Gambier, Austral and Society Archipelagos and differs from its closest relatives primarily in sensory pore pattern, having cuplike male urogenital papilla, and in lacking prominent dark pigmentation on the base of the pectoral fin. Three other new species, E. dorsimaculata, E. lacrimosa and E. deminuta, are known only from the Marquesas Islands and are distinguished from congeners by differences in pigmentation, sensory pore pattern, urogenital papilla shape, the number of rays in the dorsal and anal fins, and the length of the fifth pelvic-fin ray. Eviota deminuta represents one of the smallest known species of Eviota and features reductions in several morphological characters, including the loss of all head pores. Three of the new species are included in a phylogenetic analysis based on mitochondrial cytochrome c oxidase-I, along with 21 additional species of Eviota.     

An integrative approach to species delineation incorporating different species concepts: a case study of Limnadopsis (Branchiopoda: Spinicaudata)

The unambiguous delineation and identification of species remain central problems in systematic and taxonomic studies. Species delineation depends on the data utilized and the species concept applied. In recent years, morphology‐based species delineation has been complemented by DNA sequence data, leading to an integrative taxonomy. Such integrative approaches, however, are hampered by the partial incongruence of the various data types with certain species concepts. In this study, we delineated Australian Limnadopsis species employing one mitochondrial (cytochrome c oxidase subunit I, COI) and one nuclear (elongation factor 1α, EF1α) marker and a morphological character apparently part of the specific mate recognition complex, and therefore potentially indicative of reproductive isolation. By integrating the data over various species concepts (e.g. the ‘biological’, ‘Hennigian’, ‘recognition’, ‘phylogenetic’ and ‘evolutionary’ species concepts), the delineation of most species becomes straightforward and unambiguous. Conflicts are particularly interesting as they reveal different aspects of speciation considering the various species concepts. Our study emphasizes the benefits of a truly integrative approach to taxonomy. By combining molecular data with morphological characters indicative of reproductive isolation, it is possible to delineate species integrating not only different data types, but also different underlying species concepts. Overall, 11 Limnadopsis species could be delineated, including all eight currently recognized species, and three so far undescribed species. Most species were congruently delineated under all species concepts. A strict application of the evolutionary species concept, however, would have further split L. parvispinus into two species on the basis of the COI data. In addition, Limnadopsis tatei is consistently split into two sympatrically occurring species under all applied species concepts. © 2011 The Linnean Society of London, Biological Journal of the Linnean Society, 2011, 104 , 575–599.     

An investigation of the cranial evolution of Asian pitvipers (Serpentes: Crotalinae), with comments on the phylogenetic position of Peltopelor macrolepis

Guo, P., Jadin, R.C., Malhotra, A. and Li, C. 2009. An investigation of the cranial evolution of Asian pitvipers (Serpentes: Crotalinae), with comments on the phylogenetic position of Peltopelor macrolepis—Acta Zoologica (Stockholm) 91 : 402–407. We investigated the evolution of 12 cranial characters of 31 species of Asian pitvipers by examining the character state changes on a consensus tree modified from broadly consistent molecular results. We found that these characters appear stable with only one intraspecific polymorphism. Nine of the 12 characters form useful synapomorphies, whereas three are ambiguous and evolutionarily plastic. Clades that are supported with numerous apomorphies are the Trimeresurus group [consisting of the recently defined genera Trimeresurus sensu Malhotra and Thorpe (2004) , Parias, Popeia, Viridovipera, Himalayophis, and Cryptelytrops] and the genera Protobothrops, Parias, and Viridovipera. Two species previously considered as congeners but now known to be distantly related, Ovophis monticola and ‘Ovophis’okinavensis, have nearly identical character states, demonstrating substantial convergence in cranial characters. Finally, we attempt to infer the phylogenetic position of Peltopelor macrolepis by comparing its cranial features with that of other pitvipers.     

An assessment of the status of Polycirridae genera (Annelida: Terebelliformia) and evolutionary transformation series of characters within the family

A phylogenetic analysis was performed to determine the monophyly of non‐monotypic genera of the terebelliform family Polycirridae, i.e. Polycirrus, Amaeana, Lysilla, and Hauchiella, and the evolution of characters among members of this clade. The monotypic genera, Enoplobranchus and Biremis, were also included, together with members of both known species in Hauchiella. Representative species were included for remaining genera: 14 species of Polycirrus, six species of Amaeana, and six species of Lysilla. Out‐groups consisted of representatives of Spionidae, Cirratulidae, and Sabellariidae, as well as several species of Telothelepodidae. A total of 40 in‐ and out‐group species were coded for 50 subjects (‘characters’) and 117 subject–predicate relationships (‘states’). Although results are consistent with recent phylogenetic studies within Terebelliformia that suggest Polycirridae monophyly, only Hauchiella was found to be monophyletic, albeit part of the more inclusive clade comprising remaining polycirrid genera. Evolutionary transformation series are discussed for selected characters in relation to the non‐monophyly of Polycirrus, Lysilla, and Amaeana. Implications for the use of supraspecific taxa as ‘taxonomic surrogates’ are highlighted. The definition of Polycirridae is emended. © 2015 The Linnean Society of London     

Phylogenetic analysis of the tribe Macropelopiini (Chironomidae: Tanypodinae): adjusting homoplasies

Macropelopiini is a widely distributed tribe of Tanypodinae, with immature stages inhabiting cool seeps, springs, and small streams. The present study evaluated the monophyly and the supporting synapomorphies within a phylogenetic context for the first time for Macropelopiini. The monophyly and the intergeneric relationships were tested by morphological evidence in a cladistic framework, and the information gained from each homoplastic character was evaluated. The monophyly of Macropelopiini is corroborated through the objective synapomorphy ‘outer fringe decreasing from base to apex ending in small spines’ in the pupa, and the subjective synapomorphies ‘tibial spurs with main teeth and short lateral tooth’ in males and ‘dorsal setae arising from prominent tubercles’ in the pupa. Fittkauimyia Karunakaran, 1969 is excluded from Macropelopiini, Gressitius Sublette & Wirth, 1980 is established as a junior synonym of Alotanypus Roback, 1971, and the new combination A lotanypus antarcticus comb. nov. is proposed. Character combination, mainly through the use of the characters with informative taxonomical value, remains an efficient tool to diagnose the Macropelopiini genera. The new genus Paggipelopia gen. nov. for P aggipelopia spaccesii gen. et sp. nov. is erected and the emendation of the species diagnosis of Wuelkerella toncekensis Añón Suárez & Sublette, 2012 is conducted. © 2015 The Linnean Society of London     

Didymodon vulcanicus J.A.Jiménez,Hedd. & Frank Müll. (Pottiaceae), a new species from tropical Africa

Didymodon vulcanicus J.A.Jiménez, Hedd. & Frank Müll. is described and illustrated as a new species from volcanic regions of tropical Africa. The species is distinguished morphologically by its lanceolate or more rarely ovate-lanceolate leaves that are strongly incurved distally when dry, acute apices, upper and middle laminal cells arranged in longitudinal rows with a low dorsal papilla over the transverse walls which reaches the two immediate cells, basal cells not or hardly differentiated from the medial cells, and the presence of gemmae in the leaf axils. Drawings and light microscope photographs of the main characters are given, and possible confusion with other closely related taxa is discussed.     

External morphology of the male of Cyclestheria hislopi (Baird, 1859) (Crustacea, Branchiopoda, Spinicaudata), with a comparison of male claspers among the Conchostraca and Cladocera and its bearing on phylogeny of the 'bivalved' Branchiopoda

The adult male of Cyclestheria hislopi, sole member of the spinicaudate conchostracan clam shrimp family Cyclestheriidae and a species of potential phylogenetic importance, is described for the first time. Several previously unknown features are revealed. Among these are (1) the morphology of the dorsal organ, which is roughly similar in shape to the supposedly homologous structure in other clam shrimps but bears a relatively large, centrally located pore unique to the species; (2) an anterior cuticular pore presumably leading to the ‘internal’ space surrounding the compound eyes, and thereby homologous to the same pore in other clam shrimps and in the Notostraca; (3) the spination and setation of the antennae and thoracopods, and (4) the mature male first thoracopods (claspers). The male claspers are paired and essentially equal in size and shape on right and left sides of the body. The second pair of thoracopods are not modified as claspers, a situation different from all other spinicaudate families but shared (plesiomorphic we propose) with the laevicaudatans and most cladocerans. The claspers bear a field of special spine-like setae on the extremity of the ‘palm’; this setal type, previously unrecognized, is unique to Cyclestheria. The palm of the clasper also bears two palps (one very small), as in other conchostracan species (both laevicaudatans and spinicaudatans). The movable finger of the clasper, modified from the thoracopod endopod, bears a row of long setae along its outer extremity, also unique. Cyclestheria exhibits a mixture of characters, some unique and others typical of the Spinicaudata (Conchostraca). Cladoceran clasper types are briefly reviewed. as are the claspers in the Spinicaudata and Laevicaudata (Conchostraca). Morphology of the clasper of Cyclestheria shows typical spinicaudate characters. It is suggested that claspers on the first thoracopods may be a synapomorphy for the Conchostraca and the Cladocera. The possible role of Cyclestheria or a Cyclestheria-like ancestor in cladoceran phylogeny is briefly discussed in light of recent suggestions (Martin and Cash-Clark, 1995) of cladoceran monophyly and possible ancestral relationships with this genus. Some possibilities concerning the phylogenetic position of Cyclestheria–either as a sister group to the rest of the Spinicaudata or as a sister group to the Cladocera—are discussed.     

Phylogeny of Arvicolinae (Mammalia,Cricetidae): utility of morphological and molecular data sets in a recently radiating clade

Phylogenetic relationships within the Arvicolinae are examined based on two genes (mitochondrial cytb, nuclear GHR exon 10) and 296 morphological, developmental, behavioural, ecological and cytogenetic characters. To inspect the phylogenetic ‘behaviour’ of individual taxa, basic maximum‐parsimony and Bayesian phylogenetic analyses were accompanied by experiments based on different data‐partition combinations, ‘slow–fast’ character weighting, and inclusion/exclusion of individual problematic taxa. Ellobius, Prometheomys and Lagurus are the most basal arvicolines; Dicrostonyx, Phenacomys and Arborimus form a clade (Dicrostonychini s.lat.); the ‘core arvicolines’ include three subclades: Lemmini (Synaptomys, Lemmus, Myopus), Clethrionomyini (Eothenomys, Myodes) and Arvicolini (Arvicola, Chionomys, Stenocranius and Microtus, the last with six monophyletic subgenera: Alexandromys, ‘Neodon’, Mynomes, Lasiopodomys, Terricola, and Microtus s.str.). Position of Ondatra and Dinaromys is uncertain, probably compromised by highly homoplastic morphological characters.     

The phylogenetic relationships of sauropod dinosaurs

A data-matrix of 205 osteological characters for 26 sauropod taxa is subjected to cladistic analysis. Two most parsimonious trees are produced, differing only in the relationships between Euhelopus, Omeisaurus and Mamenchisaurus. The monophyly of the Euhelopodidae (including Shunosaurus) is supported by seven synapomorphies. The Cetiosauridae (Patagosaurus, Cetiosaurus and Haplocanthosaurus) is paraphyletic with respect to the Neosauropoda. The latter clade divides into two major radiations–the ‘Brachiosauria’ (Camarasaurus, brachiosaurids and titanosauroids), and the Diplodocoidea (nemegtosaurids, dicraeosaurids, diplodocids and Rebbachisaurus). Further evidence for the inclusion of Opisthocoelwaudia in the Titanosauroidea is presented. Phuwiangosaurus, a problematic sauropod from Thailand, may represent one of the most plesiomorphic titanosauroids. ‘Peg’-like teeth have evolved at least twice within the Sauropoda. The postspinal lamina, on the neural spines of middle and caudal dorsal vertebrae, represents a neomorph rather than a fusion of pre-existing structures. Forked chevrons may have evolved convergently in the Euhelopodidae and the diplodocid-dicraeosaurid clade, or they may have been acquired early in sauropod evolution and subsequently lost in the ‘Brachiosauria’. The strengths and weaknesses of the data-matrix and tree topologies are explored using bootstrapping, decay analysis and randomization tests. Several nodes are only poorly supported, but this seems to reflect the large proportion of missing data in the matrix (～46%), rather than an abnormally high level of homoplasy. The results of the randomization tests indicate that the ‘data-matrix’ probably contains a strong phylogenetic ‘signal’. The relationships of some forms, such as Haplocanthosaurus, are influenced by the inclusion or exclusion of certain taxa with unusual combinations of character states. Such a result suggests that there are dangers inherent in the view that ‘higher’ level sauropod phylogeny can be accurately reconstructed using only a small number of well-known taxa.     

Are Polyphaga (Coleoptera) really a basal neopteran lineage – a reply to Kazantsev

In a study on the mandible and mandibular articulation of larvae of the lycid genus Platerodrilus Kazantsev proposes a phylogenetic scheme with Polyphaga as a basal group of Neoptera and Lycidae as a basal group within Polyphaga. Here we point out different problems with his interpretation. The taxon sampling was not sufficient. The characters of endopterygote larvae cannot be compared to characters of adults in a phylogenetic context. The neotenic characters of female and adult male Lycidae are not sufficiently taken into account. A phylogenetic hypothesis should be based on multiple character systems and all available data must be considered. Kazantsev based his conclusions on a single isolated character complex. His hypothesis is in deep conflict with a phylogeny based on the molecular data, which clearly show that Lycidae are nested within Elateroidea. The molecular and morphological evidence also implies that females are aberrant neotenic forms and by no means ‘primitive’. Kazantsev's hypothesis is problematic because the presented data are insufficient and the character evaluation is not based on a numerical analysis.     

Evolution of sperm morphology in potamid freshwater crabs (Crustacea: Brachyura: Potamoidea)

We investigated sperm cells and spermatophores of four species of Old World freshwater crabs belonging to three different genera of the subfamily Potaminae (family Potamidae). Characters previously believed to be apomorphic for the potamid subfamily Potamiscinae were also found to occur in the Potaminae. To infer the morphological ancestral character state combination of the Potamidae, ancestral character state analysis of four different sperm traits was performed, based on a 16S rDNA phylogeny of the investigated species. Comparing molecular phylogeny and character state distribution, several cases of convergent evolution could be identified. The densely packed, coenospermic spermatophores and the occurrence of a ‘tongue‐and‐groove’ connection between operculum and acrosomal zones are probably apomorphies for the whole Potamidae. The spermatozoa of Socotrapotamon socotrense show several unique characters. We also analysed the evolution of acrosome size. The sperm cells of the Potamidae and their sister‐group Gecarcinucidae only slightly overlap in acrosome size. Within the investigated species, the ‘East Asia’ subclade (subfamily Potamiscinae) developed significantly larger acrosomes than the subfamily Potaminae. Our results suggest that the use of brachyuran acrosome morphology for phylogenetic inference at the family level is strongly affected by small sample size, and by convergent character evolution. © 2010 The Linnean Society of London, Zoological Journal of the Linnean Society, 2010.     

Discrete and morphometric traits reveal contrasting patterns and processes in the macroevolutionary history of a clade of scorpions

Many palaeontological studies have investigated the evolution of entire body plans, generally relying on discrete character‐taxon matrices. In contrast, macroevolutionary studies performed by neontologists have mostly focused on morphometric traits. Although these data types are very different, some studies have suggested that they capture common patterns. Nonetheless, the tests employed to support this claim have not explicitly incorporated a phylogenetic framework and may therefore be susceptible to confounding effects due to the presence of common phylogenetic structure. We address this question using the scorpion genus Brachistosternus Pocock 1893 as case study. We make use of a time‐calibrated multilocus molecular phylogeny, and compile discrete and traditional morphometric data sets, both capturing the overall morphology of the organisms. We find that morphospaces derived from these matrices are significantly different, and that the degree of discordance cannot be replicated by simulations of random character evolution. Moreover, we find strong support for contrasting modes of evolution, with discrete characters being congruent with an ‘early burst’ scenario whereas morphometric traits suggest species‐specific adaptations to have driven morphological evolution. The inferred macroevolutionary dynamics are therefore contingent on the choice of character type. Finally, we confirm that metrics of correlation fail to detect these profound differences given common phylogenetic structure in both data sets, and that methods incorporating a phylogenetic framework and accounting for expected covariance should be favoured.     

DNA barcodes for the pipefish genus Corythoichthys (Actinopterygii: Syngnathiformes) from the Indian Ocean provide insights into cryptic diversity

The syngnathiform genus Corythoichthys comprises a group of taxonomically complex, tail-brooding (Syngnathinae) pipefishes widely distributed in the Indo-Pacific region. Due to the presence of overlapping interspecific morphological characters, reliable taxonomic information on Corythoichthys is still lacking. Using 52 CO1 sequences, including seven newly generated, a phylogenetic analysis was carried out to understand the genetic diversity, distribution and ‘species groups’ within the genus Corythoichthys. Species delimitation using Automatic Barcode Gap Discovery (ABGD) analysis confirmed the presence of 13 species which include ‘species-complexes’ previously considered as a single taxon. Our results revealed the presence of three species groups, ‘C. amplexus’, ‘C. conspicillatus’ and ‘C. haematopterus’ and four unidentified/undescribed species in the wider Indo-Pacific realm. Interestingly, 60 sequences and a mitogenome identified as Corythoichthys in GenBank are misidentified at the genus level. Based on our findings, we suggest that the taxonomy and systematics of Corythoichthys need to be re-examined and validated using integrative methods, and care should be taken while selecting specimens for genetic studies.     

MOLECULAR ANALYSIS REVEALS CRYPTIC DIVERSITY IN PORPHYRA (RHODOPHYTA)1

The small subunit ribosomal RNA (SSU rRNA) gene was amplified from 15 species of the red alga Porphyra and digested with restriction enzymes to generate data for species identification. The subset of species selected for phylogenetic analysis was P. cuneiforms (Setchell et Hus) Krishnamurthy, P. nereocystis anderson, P. schizophylla Hollenberg et Abbott, P. thuretii Setchell et Dawson and Porphyra 1674. Bangia sp. was used as an out-group. Restriction sites were mapped and used as characters in parsimony and maximum likelihood analysis. The phylogenetic hypotheses generated were compared statistically to possible alternative phylogenies based on traditional morphological taxonomic characters. The results indicate that the current subgenera in Porphyra do not represent monophyletic groups and that traditional morphological and ecological taxonomic characters alone may not be adequate for definitive species identification and cannot be relied on as an indication of Porphyra have large insertions in the SSU gene that are apparently splicesd from the final SSU rRNA molecule. The possible character, distribution and potential significance of these putative introns are discussed.