Paedomorphosis and skull structure in Malagasy chamaeleons (Reptilia: Chamaeleoninae)

The phylogenetic analysis of skull characteristics, along with data derived from lung and hemipenial morphology, does not support monophyly of the predominantly terrestrial chamaeleons, Brookesiinae ( Brookesia plus Rhampholeon ), as sister-taxon of a monophyletic clade of arboreal chamaeleons, the Chamaeleoninae. Instead, the phylogenetic interrelationships of chamaeleonine lizards are ( Brookesia ("Rhampholeon" (Bradypodion, Chamaeleo) ). The monophyly of the genus Rhampholeon is not demonstrated. The arboreal chamaeleons form a monophyletic group comprising two genera, Bradypodion and Chamaeleo. Bradypodion may be placed as sister-group of the genus Chamaeleo , but its phyletic position and monophyly cannot at present be corroborated.
This study documents that there is a high degree of intraspecific variability in skull characters which may be due to paedomorphic reduction in the skull, especially of small species. Characters affected by a variable degree of ossification include the separation of a prefrontal fontanelle, the contact of the squamosal with the parietal, the size and position of the fenestra vestibuli, the degree of ossification in the basicranial rim of the fenestra, the extent of ossification of the pterygoid wing, and the shape of the skull roof as indicated by the bones forming the dorsal margin of the orbit. The closure of the lateral aperture of the occipital recess might indicate that miniaturization, and concomitant paedomorphosis, may have played a role in the initial phases of chamaeleonine phylogeny.     

Molecular phylogenetics and mitochondrial genomic evolution in the chamaeleonidae (Reptilia,Squamata)

A phylogenetic hypothesis for the lizard family Chamaeleonidae is generated from 1503 aligned base positions (883 parsimony-informative) of mitochondrial DNA for specimens representing 59 species (57 ingroup and two outgroup). Sequences are reported for a genomic segment encoding eight transfer RNAs, NADH dehydrogenase component 2 (ND2), and portions of NADH dehydrogenase component 1 (ND1) and cytochrome c oxidase subunit 1 (COI). Newly reported genomic rearrangements and duplications support the hypothesis that mitochondrial gene order and content are destabilized by phylogenetic loss of a functional origin for light-strand replication between the genes encoding tRNA(Asn) and tRNA(Cys). A novel gene order characterizes all sampled Brookesia except B. nasus. Brookesia nasus, the apparent sister taxon of a clade formed by all other Brookesia, has the ancestral gene order but contains a large tandem duplication. An apparently noncoding 220 base pair insertion between the genes encoding ND2 and tRNA(Trp) is reported for Bradypodion tavetanum. Phylogenetic analysis identifies nine clades whose ancestral lineages diverged early in chamaeleonid evolutionary history: (1) Brookesia (possibly excluding B. nasus), (2) Chamaeleo subgenus Chamaeleo (excluding C. namaquensis), (3) Chamaeleo subgenus Trioceros, (4) viviparous Bradypodion, (5) oviparous Bradypodion, (6) genus Furcifer (except F. balteatus), and (7-9) three distinct clades of Calumma. Chamaeleo namaquensis, Brookesia nasus, Furcifer balteatus, Rhampholeon brevicaudatus, and R. spectrum represent ancient lineages dating to approximately the same time. Multiple independent losses and a possible secondary gain of horns are inferred for Trioceros. Viviparity has at least two separate origins in chameleons, one in Bradypodion and     

Systematics, speciation and biogeography of the dwarf chameleons (Brookesia; Reptilia, Squamata, Chamaeleontidae) of northern Madagascar

Brookesia dwarf chameleons, endemic to Madagascar, were surveyed at the following localities in northern Madagascar (north of 16°S): Montagne d'Ambre, Ankarana, Manongarivo, Tsaratanana, Marojejy and Masoala. A total of 15 species occur in this region. Six new species are described and five new synonyms are identified. The genus Brookesia , the most speciose chamaeleontid genus in Madagascar, contains 23 species.
Almost all the northern Brookesia species are restricted to rainforest and occupy a relatively narrow elevational range. Although the northern rainforests represent just one-third of the total rainforest and about 5% of the total island area, 65% of the Brookesia species occur in this region, and 52% are endemic to the northern rainforest. Five new biogeographic regions of the northern rainforest are identified based on centres of Brookesia endemicity: Montagne d'Ambre, Northwest, Tsaratanana, Northeast and East. Speciation is thought to have been facilitated in the north through geographic isolation, with the Tsaratanana mountain range and the dry forests south of Montagne d'Ambre forming barriers to dispersal, and the Tsaratanana mountains acting as a centre of isolation. The fragmented distribution of several Brookesia species of low altitude rainforest suggests a period in Madagascar's history when the climate was wetter and low altitude rainforest much more widespread.     

Acanthocephalans from some frogs and toads (Anura) and chameleons (Squamata) from Tanzania with the description of a new species

The following Acanthocephala, all Echinorhynchidae, were found on examination of 229 amphibians and 191 reptiles collected in the Eastern Arc Range, Tanzania: Acanthocephalus bufonis from the frogs Arthroleptis stenodactylus and Arthroleptides martiensseni, the toad Nectophnyroides viviparous, and the chameleon Rhampholeon brevicaudatus; Pseudoacanthocephalus betsileo from the frogs Probreviceps macrodactylus and Ptychadero anchietae; and Pseudoacanthocephalus rhampholeontos n. sp. from the chameleons Rhampholeon sp. and Rhampholeon uluguruensis. Pseudoacanthocephalus rhampholeontos differs from the only other acanthocephalan occurring in chameleons, Pseudoacanthocephalus bigueti, in being a larger worm with fewer, smaller hooks in the proboscis armature. The status of the Acanthocephalus and Pseudoacanthocephalus is still problematic and requires further attention and study.     

A phylogenetic review of the African leaf chameleons: genus Rhampholeon (Chamaeleonidae): the role of vicariance and climate change in speciation

The phylogenetic associations among 13 currently recognized African leaf chameleon species were investigated by making use of mitochondrial and nuclear DNA sequence data (44 taxa and 4145 characters). The gene tree indicates two divergent clades within Rhampholeon; this finding is congruent with previous morphological suggestions. The first clade (I) comprises three taxa (R. kerstenii, R. brevicaudatus and R. brachyurus) and is widely distributed in lowland forest and or non-forest biomes. The second clade (II) comprises the remaining Rhampholeon species and can be subdivided into three subclades. By contrast, most taxa belonging to clade II are confined to relict montane forest biotopes. Based on geographical, morphological and molecular evidence, it is suggested that the taxonomy of Rhampholeon be revised to include two genera (Rieppeleon and Rhampholeon) and three subgenera (Rhampholeon, Bicuspis and Rhinodigitum). There is a close correlation between geographical distribution and phylogenetic relatedness among Rhampholeon taxa, indicating that vicariance and climate change were possibly the most influential factors driving speciation in the group. A relaxed Bayesian clock suggests that speciation times coincided both with the northern movement of Africa, which caused the constriction of the pan African forest, and to rifting in east Africa ca. 20 Myr ago. Subsequent speciation among taxa was probably the result of gradual desiccation of forests between 20 and 5 Myr ago.     

Field observations on some dwarf chameleons (Brookesia spp.) from rainforest areas of Madagascar, with description of a new species

Six species of Brookesia dwarf chameleons were recorded during two rainforest expeditions in Madagascar. One of these is described as a new species Brookesia valerieae based on the arrangement of the nine pairs of dorso-lateral spines, the lack of a pelvic shield, and dorsal chevron markings. Observations were made on the defence and roosting behaviours shown by these six species. Aspects concerning the evolution and conservation in Madagascar are discussed for this poorly studied group of endemic Malagasy reptiles.     

THE PHYLOGENETIC RELATIONSHIPS AMONG REQUIEM AND HAMMERHEAD SHARKS: INFERRING PHYLOGENY WHEN THOUSANDS OF EQUALLY MOST PARSIMONIOUS TREES RESULT

Abstract— Protein variation among 37 species of carcharhiniform sharks was examined at 17 presumed loci. Evolutionary trees were inferred from these data using both cladistic character and a distance Wagner analysis. Initial cladistic character analysis resulted in more than 30 000 equally parsimonious tree arrangements. Randomization tests designed to evaluate the phylogenetic information content of the data suggest the data are highly significantly different from random in spite of the large number of parsimonious trees produced. Different starting seed trees were found to influence the kind of tree topologies discovered by the heuristic branch swapping algorithm used. The trees generated during the early phases of branch swapping on a single seed tree were found to be topologically similar to those generated throughout the course of branch swapping. Successive weighting increased the frequency and the consistency with which certain clades were found during the course of branch swapping, causing the semi-strict consensus to be more resolved. Successive weighting also appeared resilient to the bias associated with the choice of initial seed tree causing analyses seeded with different trees to converge on identical final character weights and the same semi-strict consensus tree.
The summary cladistic character analysis and the distance Wagner analysis both support the monophyly of two major clades, the genus Rhizoprionodon and the genus Sphyrna. . The distance Wagner analysis also supports the monophyly of the genus Carcharhinus . However, the cladistic analysis suggests that Carcharhinus is a paraphyletic group that includes the blue shark Prionace glauca .     

Phylogenetic systematics of the colorful, cyanide-producing millipedes of Appalachia (Polydesmida, Xystodesmidae, Apheloriini) using a total evidence Bayesian approach

Here, we provide an exemplar-approach phylogeny of the xystodesmid millipede tribe Apheloriini with a focus on genus-group relationships-particularly of the genus Brachoria. Exemplars for the phylogenetic analysis were chosen to represent the maximum breadth of morphological diversity within all nominal genera in the tribe Apheloriini, and to broadly sample the genus Brachoria. In addition, three closely related tribes were used (Rhysodesmini, Nannariini, and Pachydesmini). Morphological and DNA sequence data were scored for Bayesian inference of phylogeny. Phylogenetic analysis resulted in polyphyletic genera Brachoria and Sigmoria, a monophyletic Apheloriini, and a "southern clade" that contains most of the tribal species diversity. We used this phylogeny to track morphological character histories and reconstruct ancestral states using stochastic character mapping. Based on the findings from the character mapping study, the diagnostic feature of the genus Brachoria, the cingulum, evolved independently in two lineages. We compared our phylogeny against prior classifications using Bayes factor hypothesis-testing and found that our phylogenetic hypothesis is inconsistent with the previous hypotheses underlying the most recent classification. With our preferred total-evidence phylogeny as a framework for taxonomic modifications, we describe a new genus, Appalachioria; supply phylogenetic diagnoses of monophyletic taxa; and provide a phylogeny-based classification for the tribe Apheloriini.     

色季拉山区高山寒带种子植物区系研究

通过对西藏色季拉山高山寒带进行实地野外调查,鉴定统计得到种子植物285种,分属于33科103属,其中双子叶植物有26科、77属、236种,裸子植物有1科、1属、4种,中国特有植物125种。对该区域种子植物区系从科、属、种三级水平统计分析,初步探讨了其植物区系的性质和基本特点。地理成分简单,但特有现象明显,在种类上缺乏古老、原始的类型;从科、属和种的分布类型统计分析,基本上都是温带成分,反映出典型的温带区系特征和区系的年青性,因而具有高寒区系的显著特色。在区系成分中存在较多中国-喜马拉雅成分,表明了该区系具有明显的高原及高山植物区系的特色。     

Molecular Phylogeny of Microsporidians with Particular Reference to Species that Infect the Muscles of Fish

Ribosomal DNA from eight species of microsporidians infecting fish have been sequenced. Seven of these species infect the skeletal muscle of fish ( Pleistophora spp.) and one species infects migratory mesenchyma cells ( Glugea anomala ). These sequences, in addition to other available microsporidian rDNA sequences from a broad range of host taxa, have been used in phylogenetic analysis. This analysis revealed that muscle-infecting microsporidians from fish are a polyphyletic group, indicating that characters supposed to be important in the classification of the genus Pleistophora have to be re-evaluated. One character that probably has a polyphyletic origin is the amorphous coat, which has been extensively used in the definition of this genus. Furthermore, our results showed that the insect parasitizing Pleistophora spp. are not related to the true pleistophorans parasitic in skeletal muscle of fish. Phylogenetic analysis of small subunit rDNA sequences revealed disagreements between the molecular phylogeny and classifications based upon ultrastruclure. Many of the morphological characters claimed to be important in microsporidian classifications appeared to have arisen several times during evolution: for example, the diplokaryon and sporophorous vesicles.     

Evolutionary patterns and processes in the genus Rosa (Rosaceae) and their implications for host-parasite co-evolution

The genus Rosa (Rosaceae) is a remarkable genus with respect to systematic biology. Multiple reproductive strategies ranging from apomixis to outcrossing including hybridisation, as well as different modes of character inheritance like matroclinal, paternal or sex unrelated ones. This complexity makes the genus a model in which simple concepts of radiation, speciation and taxonomy come to their limits. Analyses of the evolutionary patterns and processes in Rosa give clear evidence for the stochastic character of this specific evolutionary scenario.     

The use of mitochondrial and nuclear sequence data in assessing the taxonomic status of the endangered Uluguru Bush Shrike Malaconotus alius

The endangered Uluguru Bush Shrike Malaconotus alius is a large, black-headed bush shrike, strictly endemic to the Uluguru Mountains in Tanzania. It has recently been suggested that this species has been misplaced within the genus Malaconotus and might instead be related to Malagasy Vangidae. To assess its systematic affinities, we analysed 1518 bp of sequence data obtained from a nuclear intron (myoglobin intron-2) and a mitochondrial protein-coding gene (ND2) using parsimony, maximum likelihood and Bayesian inference. Both genes strongly support the traditional placement within the genus Malaconotus , suggesting that similarities between the Uluguru Bush Shrike and the Vangidae are due to convergence. These results caution that taxonomic changes should not be made without a proper character analysis (i.e. assignment of character homology).     

The sesquiterpenoids and their chemotaxonomic implications in Senecio L. (Asteraceae)

Sesquiterpenoids are important characteristic compounds in Asteraceae plants. These compounds have been proposed to be potential chemotaxonomic markers, but this application has not been comprehensively investigated. In this paper, sesquiterpenoids from 149 species of the genus Senecio were investigated to assess their taxonomic utility. The presence and absence were encoded as binary taxonomic characteristics and subsequently utilised in a clustering analysis. The previously biosynthesis pathway of sesquiterpenoids was taken into account to explore the relationship among these species contained different sesquiterpenoid types. In addition, the DNA phylogeny was also considered to explore the distribution and evolution of sesquiterpenoids in genus Senecio further. As a result, seven chemical major sections within the Senecio were recognised based on the chemical character. Although with several exceptions, the biosynthesis pathway, molecular phylogeny and the geographical origin of these sesquiterpenoid were found to be related to the chemical sections, which largely confirmed the validity of our chemo-classification for genus Senecio. In conclusion, we suggest that the sesquiterpenoid character in Senecio has some value for the genus taxonomy but should be analysed carefully and critically.     

Rivaling the world's smallest reptiles: discovery of miniaturized and microendemic new species of leaf chameleons (Brookesia) from northern Madagascar

Background

One clade of Malagasy leaf chameleons, the Brookesia minima group, is known to contain species that rank among the smallest amniotes in the world. We report on a previously unrecognized radiation of these miniaturized lizards comprising four new species described herein.

Methodology/Principal Findings

The newly discovered species appear to be restricted to single, mostly karstic, localities in extreme northern Madagascar: Brookesia confidens sp. n. from Ankarana, B. desperata sp. n. from Forêt d''Ambre, B. micra sp. n. from the islet Nosy Hara, and B. tristis sp. n. from Montagne des Français. Molecular phylogenetic analyses based on one mitochondrial and two nuclear genes of all nominal species in the B. minima group congruently support that the four new species, together with B. tuberculata from Montagne d''Ambre in northern Madagascar, form a strongly supported clade. This suggests that these species have diversified in geographical proximity in this small area. All species of the B. minima group, including the four newly described ones, are characterized by very deep genetic divergences of 18–32% in the ND2 gene and >6% in the 16S rRNA gene. Despite superficial similarities among all species of this group, their status as separate evolutionary lineages is also supported by moderate to strong differences in external morphology, and by clear differences in hemipenis structure.

Conclusion/Significance

The newly discovered dwarf chameleon species represent striking cases of miniaturization and microendemism and suggest the possibility of a range size-body size relationship in Malagasy reptiles. The newly described Brookesia micra reaches a maximum snout-vent length in males of 16 mm, and its total length in both sexes is less than 30 mm, ranking it among the smallest amniote vertebrates in the world. With a distribution limited to a very small islet, this species may represent an extreme case of island dwarfism.     

The systematic relationships of the snake genus Anomochilus

Phylogenetic analysis of 38 skeletal characters, 12 muscular characters and 15 visceral characters in 17 major snake clades plus Anomochilus suggests that Anomochilus is the sister taxon of all other living alethinophidian snakes. However, skeletal, muscular and visceral character sets analysed separately or in pairs give four groups of nonconcordant tree topologies. Based on the cladogram derived from the total evidence, two families are erected to prevent the existing family Uropeltidae from becoming paraphyletic: Anomochilidae, for the Malaysian and Indonesian genus Anomochilus , and Cylindrophiidae, for the Sri Lankan, Southeast Asian and Indonesian genus Cylindrophis and the Upper Eocene fossil Eoanilius.     

A cladistic analysis ofAnisopappus (Asteraceae: Inuleae)

A cladistic analysis of the genusAnisopappus (Asteraceae: Inuleae) has been undertaken. A hypothesis of species interrelationships in the genus is presented for the first time. The analysis also includedArctotis (Arctoteae), used as outgroup, and five additional genera from theInuleae: Geigeria, Calostephane, Asteriscus, Buphthalmum, Pulicaria, andInula. It is concluded thatAnisopappus is a monophyletic group situated at the base of the tribe, diagnosed by, e.g., their obtuse stylar sweeping-hairs. The species with acute sweeping-hairs were found to be derived within the genus. Problems concerning species delimitation, biogeography and character evolution in the genus are briefly discussed.