Gracilis Complex Research Articles

Morphology, vocalizations, and mitochondrial DNA suggest that the Graceful Prinia is two species

Abstract Prinias (Cisticolidae: Prinia) are resident warblers of open areas across Africa and Asia and include many polytypic species whose species limits have not been seriously reevaluated recently. Based on an integrative taxonomic analysis of morphology, song, and mitochondrial DNA (mtDNA), we suggest that 2 species should be recognized in the Graceful Prinia (Prinia gracilis) complex. In addition, our morphological analyses show the existence of a well-marked undescribed form in southeastern Somalia, which we name herein as a new subspecies. Prinia gracilis is a small, drab, long-tailed species with streaking above and plain pale underparts that has been suggested to fall into 2 groups: the southwestern nominate group (from Egypt to Oman) and the northeastern lepida group (from Turkey through India). However, the characters presented to justify this grouping are variable and show a mosaic pattern, and whether genetic and vocal differences exist is unknown. We found consistent between-group song differences, with the nominate group giving consistently longer inter-phrase intervals, whereas the members of the lepida group sing an essentially continuous reel. An mtDNA tree suggests a deep split between the nominate and lepida groups, with a coalescence time between these clades of ~ 2.2 million years ago. Vocal and mtDNA analyses provided evidence that the northeastern Arabian Peninsula taxon carpenteri belongs to the lepida group. We found that, of all the morphological characters proposed, only proportions and tail barring and spotting relatively consistently distinguish the 2 groups. However, these characters strongly suggest that the eastern Arabian Peninsula is populated by taxa of both the gracilis and lepida groups, in different areas, but we lack genetic and bioacoustic data to corroborate this. Although further study is needed in potential contact zones, we suggest that 2 species should be recognized in the P. gracilis complex, and we propose the retention of the English name Graceful Prinia for P. gracilis sensu stricto, while we suggest that P. lepida be known as Delicate Prinia.

A new blind snake of the genus Letheobia (Serpentes: Typhlopidae) from Rwanda with redescriptions of L. gracilis (Sternfeld, 1910) and L. graueri (Sternfeld, 1912) and the introduction of a non-invasive preparation procedure for scanning electron microscopy in zoology.

A new species of blind snake in the genus Letheobia is described from Akagera National Park in eastern Rwanda. The new species is most similar to species of the L. gracilis complex, particularly L. gracilis and L. graueri. It differs from all other species of the genus by a unique combination of morphological characters, including the highest number of middorsal scale rows (834) and the most extreme elongation (total-length/midbody-width ratio 131) of all species in the genus and of any species of snake in the world; 22-22-22 longitudinal scale rows; snout in dorsal profile rounded, in lateral profile bluntly rounded with an angular horizontal edge ventrally; rostral broad, posteriorly rounded; eyes invisible; supralabial imbrication pattern T-0; tail short (1.3 percent of total length) with an apical spine; and a pink life colouration. The holotype of the new species was collected in gallery forest at a lake shore surrounded by savanna at 1300 m elevation. We produced scanning electron microscope images of the heads of the investigated specimens applying a liquid-substitution preparation procedure which does not require coating or drying and thus does not irreversibly damage the investigated samples. The obtained images allow an easy and more accurate examination of the scalation.

Pleistocene range shifts, refugia and the origin of widespread species in western Palaearctic water beetles

Quaternary glacial cycles drove major shifts in both the extent and location of the geographical ranges of many organisms. During glacial maxima, large areas of central and northern Europe were inhospitable to temperate species, and these areas are generally assumed to have been recolonized during interglacials by range expansions from Mediterranean refugia. An alternative is that this recolonization was from non-Mediterranean refugia, in central Europe or western Asia, but data on the origin of widespread central and north European species remain fragmentary, especially for insects. We studied three widely distributed lineages of freshwater beetles (the Platambus maculatus complex, the Hydraena gracilis complex, and the genus Oreodytes), all restricted to running waters and including both narrowly distributed southern endemics and widespread European species, some with distributions spanning the Palearctic. Our main goal was to determine the role of the Pleistocene glaciations in shaping the diversification and current distribution of these lineages. We sequenced four mitochondrial and two nuclear genes in populations drawn from across the ranges of these taxa, and used Bayesian probabilities and Maximum Likelihood to reconstruct their phylogenetic relationships, age and geographical origin. Our results suggest that all extant species in these groups are of Pleistocene origin. In the H. gracilis complex, the widespread European H. gracilis has experienced a rapid, recent range expansion from northern Anatolia, to occupy almost the whole of Europe. However, in the other two groups widespread central and northern European taxa appear to originate from central Asia, rather than the Mediterranean. These widespread species of eastern origin typically have peripherally isolated forms in the southern Mediterranean peninsulas, which may be remnants of earlier expansion-diversification cycles or result from incipient isolation of populations during the most recent Holocene expansion. The accumulation of narrow endemics of such lineages in the Mediterranean may result from successive cycles of range expansion, with subsequent speciation (and local extinction in glaciated areas) through multiple Pleistocene climatic cycles.

The Syllis gracilis species complex: A molecular approach to a difficult taxonomic problem (Annelida, Syllidae)

Syllis gracilis is an emblematic member of the subfamily Syllinae (Syllidae, Annelida), which inhabits shallow, temperate coastal waters and can be found on algae, coral rubble, and sponges. Their distinctive ypsiloid chaetae, usually found in specimens from populations all around the world, led to the consideration of the species as cosmopolitan, even though four other species have similar chaetae: Syllis magellanica, S. picta, S. mayeri and S. ypsiloides. The discovery of deeply divergent lineages in the Mediterranean Sea, that were morphologically similar, questioned the cosmopolitanism of S. gracilis and suggested the possibility of it being a species complex. In order to assess the speciation patterns within the putative S. gracilis complex, we undertook species delimitation and phylogenetic analyses on 61 specimens morphologically ascribed to Syllis gracilis and closely related species using a multilocus molecular dataset (two mitochondrial and two nuclear markers). Our results suggest high levels of genetic differentiation between the S. gracilis populations analyzed, some of which have morphologically distinctive features. Five to eight distinct lineages (depending on the analysis) were identified, all with geographically restricted distributions. Although the presence of ypsiloid chaetae has been traditionally considered the main character to identify S. gracilis, we conclude that this feature is homoplastic. Instead, we propose that characters such as the degree of fusion of blades and shafts in chaetae, the morphology of the posterior chaetae or the animal color pattern should be considered to differentiate lineages within the S. gracilis species complex. Our study does not support the cosmopolitanism of S. gracilis, and instead provides morphological and molecular evidence of the existence of a complex of pseudo-cryptic species.

Review of the Frog GenusSilverstoneia, with Descriptions of Five New Species from the Colombian Chocó (Dendrobatidae: Colostethinae)

The dendrobatid genus Silverstoneia is a clade of forest-dwelling frogs that share small adult size (<22 mm snout-vent length), basal webbing between toes III–IV, a solid blackish brown flank divided by a conspicuous pale oblique lateral stripe from the groin to the eye, a pale ventrolateral stripe, finger I > II, male nurse frogs (known in four species), and larvae possessing an umbelliform oral disc with few to many submarginal papillae and medially emarginate posterior labium (also known in four species).The clade is distributed from Costa Rica to southern Departamento del Valle del Cauca in western Colombia and includes eight species, five of which are described herein as new species. As in all species of Dendrobatoidea, in Silverstoneia the distal tendon of insertion of the m. semitendinosus inserts dorsad to the distal tendon of the mm. gracilis complex and is strapped to the dorsal edge of the inner surface of the mm. gracilis complex by a unique binding tendon. The species of Silverstoneia may be diagnosed on the basis of adult size, adult ventral coloration, thigh coloration, and degree of expansion of finger III in adult males; additionally, there are clear species differences among the known tadpoles.Taxonomic comments are given for three previously named species: Silverstoneia erasmios (Rivero and Serna), S. flotator (Dunn), and S. nubicola (Dunn). We were unable to distinguish erasmios from nubicola. However, only females of erasmios are known and its validity needs confirmation. The species S. flotator sensu lato and S. nubicola sensu lato occur north through Panama to Costa Rica; they are distinct from one another, but some intraspecific variation suggests the possible presence of unnamed sibling species. The specimen long recognized as the type of S. flotator is not the holotype, which we consider lost; however, ample material is available from the well-known type locality (Barro Colorado Island) and neotype designation is not needed.Five new species are described—all endemic to low and moderate elevations on the Pacific versant of Colombia: Silverstoneia dalyi (p. 5), S. gutturalis (p. 17), S. minima (p. 22), S. minutissima (p. 29), and S. punctiventris (p. 34).

Phylogeny-Based Species Delimitation In Philippine Slender Skinks (Reptilia: Squamata: Scincidae) III: Taxonomic Revision of the Brachymeles Gracilis Complex, With Descriptions of Three New Species

Abstract: Species diversity in skinks in the genus Brachymeles recently has undergone a state of flux, with numerous taxonomic discoveries over the past few years. Newly available, robust data sets from morphological data and molecular sequences have revealed that taxonomic diversity within this unique group of lizards is substantially underestimated. In this third recent monographic revision of a major Brachymeles clade, we review the medium-sized, pentadactyl species of the Brachymeles gracilis Complex (now known to include B. pathfinderi) and describe three new species in this unique clade of endemic Philippine lizards. For more than three decades B. gracilis has been recognized as a single polytypic, “widespread” species. The species' wide geographic range has persisted as a result of weak sampling, morphologically similar body sizes, scale pigmentation, and patterns of scalation among populations. However, previous authors have noted morphological variation between populations on different islands, ...

Phylogenetic relationships and species delimitation of New Zealand bluebells (Wahlenbergia, Campanulaceae) based on analyses of AFLP data

Phylogenetic and phenetic analyses of amplified fragment length polymorphism (AFLP) data were used to compare 38 individuals of 17 species of Australasian Wahlenbergia, with a focus on the New Zealand representatives. Overall, support values were slightly higher in the AFLP analyses than in previously published DNA sequence analyses, indicating the marginally better phylogenetic resolution of this technique. However, higher support was generally found towards the tips of the branches, whereas deeper relationships were equally poorly supported using either AFLPs or DNA sequence data. AFLP analyses are useful for species delimitation in New Zealand Wahlenbergia. The four members of the lowland radicate Wahlenbergia gracilis complex may all belong to the same species. We also present evidence that Wahlenbergia vernicosa should not be considered a subspecies of the Australian Wahlenbergia littoricola. The morphologically distinctive Wahlenbergia matthewsii and Wahlenbergia congesta subsp. haastii were recovered as being distinct using AFLP analyses, but members of the alpine rhizomatous Wahlenbergia albomarginata/ Wahlenbergia pygmaea complex could not be distinguished from each other.

Morphological reply to a DNA call: a new cryptic species of Hydraena from western Europe, with a complete overview of the Hydraena gracilis complex (Coleoptera: Hydraenidae: “Haenydra” lineage)

Recent molecular analyses revealed unexpected genetic variability within Hydraena gracilis, one of the most common and widespread European moss beetles, belonging to the West Palaearctic endemic “Haenydra” lineage. For this taxon, molecular data univocally evidenced two distinct clades, the first one including populations from the Iberian Peninsula, and the second including populations from central and eastern Europe. Aedeagal morphology of H. gracilis was further investigated, finally demonstrating the actual existence of a new cryptic species of the H. gracilis complex in Portugal, Spain and the French Pyrenees. The geographical range of the true H. gracilis was consequently revised. Finally, dichotomous keys for males of all species belonging to the H. gracilis complex, and for males of all the Iberian “Haenydra” species, are also supplied.

An expanded molecular phylogeny of the southern bluebells (Wahlenbergia, Campanulaceae) from Australia and New Zealand

We used nuclear and chloroplast DNA markers to examine relationships and test the current morphology-based taxonomy of several species and subspecies of Australian and New Zealand Wahlenbergia. We sampled nuclear ribosomal ITS regions and the chloroplast regions trnL–F and trnK–psbA from 105 individuals, representing 29 of the 46 species and subspecies currently recognised in New Zealand and Australia. Our phylogeny was incompletely resolved because of low levels of genetic variation in all three markers and some conflict between ITS and chloroplast markers. The New Zealand rhizomatous species appear to have radiated in New Zealand after a single long-distance dispersal event from Australia, but it is unclear to which species in Australia they are most closely related. The New Zealand radicate species do not form a clade; instead they are shown to be very closely related to many Australian radicate species. The four species in the New Zealand lowland radicate W. gracilis complex may all belong to the same morphologically variable species. In contrast, the other New Zealand radicate species, W. vernicosa, is probably a separately evolving lineage, and is not conspecific with the W. gracilis complex, nor the Australian W. littoricola, as previously hypothesised. Two of the New Zealand rhizomatous species, W. albomarginata and W. pygmaea, may be conspecific. By contrast, the morphologically distinctive New Zealand rhizomatous W. cartilaginea, W. matthewsii and W. congesta subsp. haastii each formed monophyletic groups. Samples of two recently described Australian species (W. rupicola and W. telfordii) formed monophyletic groups consistent with their recognition.

Convergent evolution in Cladonia gracilis and allies

AbstractMembers of the Cladonia gracilis group of lichen fungi are common terrestrial lichens where morphological features are more similar between members of the C. gracilis species complex and allied species outside the complex than they are between subspecies within the complex. The objectives of this study were to examine whether the Cladonia gracilis species complex is monophyletic, to determine whether morphological similarity is supported by genetic variation, and to examine the utility of the polyketide synthase (PKS) gene for phylogenetic studies among closely related species. Two loci, the ketosynthase region of the PKS gene and the internal transcribed spacer (ITS) region of nuclear ribosomal DNA, were sequenced and analysed by Maximum Parsimony, Bayesian and haplotype network analyses. Functional differences were also inferred through ITS2 RNA secondary structures and non-synonymous changes in translated PKS amino acid sequences. The monophyly of the C. gracilis complex is supported by 71% bootstrap in the ITS phylogeny, and 92% bootstrap with greater than 95% posterior probability in the PKS phylogeny. Morphological similarity is not always supported by genetic similarity. The PKS gene is less variable than the ITS but the PKS supports species hypotheses that are reflected in the ITS2 RNA model. We conclude that monophyly of the C. gracilis complex can be supported if C. cornuta, C. coniocraea and C. ochrochlora are included in the complex. In addition, C. maxima, C. phyllophora and C. subchordalis are supported as monophyletic species outside the C. gracilis complex. Cladonia maxima may form a separate species and variation among podetial morphology may be explained by convergent evolution.

A new species of poeciliid fish, Poeciliopsis santaelena, from Peninsula Santa Elena, Area de Conservación Guanacaste, Costa Rica

An undescribed freshwater fish was recently discovered during a biological inventory of Area de Conservaci6n Guanacaste, northwestern Costa Rica. This new species of Poeciliopsis is closely related to a group of widespread species of small spotted fishes designated as the Poeciliopsis gracilis complex in this study. The complex extends on both versants from southern Mexico to Nicaragua, and with this new finding, extends into Costa Rica. The new species is distinguished from its Central American relatives by its lack of lateral and ventral markings, higher pectoral and caudal-fin counts and more posterior placement of the dorsal fin. Poeciliopsis santaelena is endemic to the Rio Potrero Grande, a river whose flow is reduced to just a few pools during the long dry season and flows fully only during very rainy weather. It is just another in a growing list of threatened or endangered species found in this unique peninsular environment.

Molecular Cloning and Nucleotide Sequence of a cDNA Encoding Euglena gracilis Cytochrome C11

The amino acid sequence of the mature protein of Euglena gracilis cytochrome c1 was determined by sequencing of its cDNA. A cDNA expression library was constructed from Euglena poly(A)+ RNA in phage lambda gt11 and screened with an antiserum raised against cytochrome c1 polypeptide isolated from purified E. gracilis complex III. An isolated cDNA clone consisted of 872 base pairs and encoded the mature protein with 243 amino acids. The deduced amino acid sequence contained the unusual heme binding sequence-Phe-Ala-Pro-Cys-His- (Mukai, K. et al. (1989) Eur. J. Biochem. 178, 649-656) instead of the typical sequence,-Cys-X-Y-Cys-His-, commonly found in C-type cytochromes. Comparison of the sequence with those of several other cytochromes c1 revealed that Euglena cytochrome c1 conserved the residues probably ligating heme-iron, those supposed to interact with cytochrome c and regions anchoring the mitochondrial inner membrane.