Chondrocranial Morphology of Leptodactylus Larvae (Leptodactylidae: Leptodactylinae): Its Utility in Phylogenetic Reconstruction

(Article was originally published in Journal of Morphology 238(3):287–305, 1998.) An incorrect version of Figure 1 was printed in the above article. The corrected version is shown below.     

Cladistic analysis and osteological descriptions of the frog species in the Leptodactylus fuscus species group (Anura, Leptodactylidae)

The genus Leptodactylus is predominantly Neotropical (a few species have colonized the southern Neartic region) and is distributed from Texas to Argentina and on certain Caribbean islands. Leptodactylus was divided into five groups of species: Leptodactylus melanonotus , Leptodactylus ocellatus, Leptodactylus fuscus , Leptodactylus pentadactylus and Leptodactylus marmoratus . Among these, the L. fuscus group is the one with most species, with 27 taxa. Characters unverified in most of the species are used to define the L. fuscus group. However, the monophyly of the group has never been tested rigorously in a quantitative phylogenetic context. Thus, the main goal of this study was to test such monophyly and to construct a phylogeny of the L. fuscus group. A matrix of 114 characters scored across 43 taxa was constructed, with 31 characters taken from external morphology, 58 from adult skeletons, 16 from larval chondrocranium, 5 from ethology and 4 from morphometric data were included. Out of all the species examined, 23 belonged to the ingroup and 20 to the outgroup. The data set was analysed with implied weights, by using TNT software. The monophyly of the group was strongly supported in the fittest cladogram obtained. The optimizations of some characters on this hypothesis support traditional evolutionary hypotheses. The optimizations also suggest the presence of paedomorphic character states in some species, which is also discussed.     

厄瓜多尔西部新热带蛙(两栖纲: 无尾目:细趾蟾科)的分布特征及生态习性

Leptodactylus labrosus属于陆地坐-等型的捕食者,其食物包括地表的、掘地的及飞行昆虫,其中蚂蚁数量最多。曾有报道Bothrops asper是其天敌。L.labrosus主要栖息于落叶及半落叶林潮湿的环境中,偶尔也栖息于常绿林中。L.labrosus分布于厄瓜多尔西海岸的北部、中部、南部;秘鲁西海岸的北部、中部,分布地海拔可达600 m;及位于南厄瓜多尔和北秘鲁海拔高达1 300 m的干燥的安第斯山谷。其分布地区包括了厄瓜多尔和秘鲁海岸的潮湿的、季节性干燥的森林。在安第斯山脉斜坡的潮湿地带,L.labrosus与其他3种细趾蟾科的分布区重叠,但表现为生境分离。其分布特征与其他几种活动区域受限的两栖动物相似。Tumbesian地区应被认为是地方特有两栖动物的分布区。Choco和Tumbesian的中间区域是L.labrosus与其他细趾蟾科的生境分布重叠区,其生态及气候特征使其形成了独特的动物区系,包括几种地方特有物种。因此该地区应被划为西厄瓜多尔地方种区域。     

First μ‐CT‐based 3D reconstruction of a dipteran larva—the head morphology of protanyderus (tanyderidae) and its phylogenetic implications

The larval head of Protanyderus was examined and documented using innovative techniques, with emphasis on internal structures. A chart listing all head muscles of dipteran larvae and other holometabolan groups is presented in the Supporting Information. The results are compared to conditions found in other nematoceran lineages. The larval head of Protanyderus is characterized mainly by plesiomorphic character states such as the complete and largely exposed head capsule, the long coronal suture, V‐shaped frontal sutures, lateral antennal insertion areas, a transverse labrum, a nearly horizontal plane of mandibular movements, mandibles lacking a movable distal part, a mesal hook and mesal or distal combs, separated maxillary endite lobes, a comparatively complete array of muscles, and a brain only partly located within the head capsule. An anteriorly toothed hypostomal plate and dense labral brushes of microtrichiae are also likely groundplan features of Diptera. The pharyngeal filter is a possible apomorphy of Diptera excl. Deuterophlebiidae (or Deuterophlebiidae + Nymphomyiidae). The messors have also likely evolved early in the dipteran crown group but are absent in the groundplan. The phylogenetic interpretation of externolateral plates with growth lines is ambiguous. Autapomorphies of Tanyderidae are differences between the third and fourth instar larvae, the roof‐like extension above the antennal insertion area, the dorsal endocarina, and the posterodorsal internal ridge. The phylogenetic position of Tanyderidae is controversial, but features of the larval head do not support a proposed sistergroup relationship between Tanyderidae and Psychodidae. Both groups differ in many features of the larval head, and we did not identify a single potential synapomorphy. Larval characters alone are insufficient for a reliable phylogenetic reconstruction, though they vary greatly and apparently contain phylogenetic information. The evaluation of these features in the context of robust molecular phylogenies will be a sound basis for the reconstruction of complex evolutionary scenarios for the megadiverse Diptera. Diptera. J. Morphol. 2012. © 2012 Wiley Periodicals, Inc.     

On the head morphology of Phyllium and the phylogenetic relationships of Phasmatodea (Insecta)

Friedemann K., Wipfler B., Bradler S. and Beutel R.G. 2011 . On the head morphology of Phyllium and the phylogenetic relationships of Phasmatodea (Insecta). —Acta Zoologica (Stockholm) 00 : 1–16. External and internal head structures of Phyllium siccifolium are described in detail. The findings are compared with conditions found in other phasmatodeans and members of other neopteran lineages. The compiled 125 characters were analysed cladistically. A clade Eukinolabia (Phasmatodea + Embioptera) was confirmed. Synapomorphies of these two taxa are the shift of the origin of M. tentorioparaglossalis to the hind margin of the prementum, the presence of M. tentorioscapalis medialis, and antennal muscles that originate exclusively on the anterior tentorial arms. Within Eukinolabia, the position of Timema remains somewhat ambiguous because of missing anatomical data. However, it was confirmed as sister group of Euphasmatodea in a monophyletic Phasmatodea. Apomorphic groundplan features of Euphasmatodea are salivary ducts with separate external openings, apically rounded glossae, the presence of the galealobulus, and the reduction of the antennifer. The monophyly of Neophasmatidae was confirmed. Autapomorphies are the loss of M. frontobuccalis posterior, the anteriorly or dorsally directed maxillary palps, and the reduction of the mandibular incisivi. The analysis of characters of the head yielded three new autapomorphies of Phylliinae, the presence of a protuberance on the attachment site of the dorsal tentorial arms, dorsoventrally flattened maxillary‐ and labial palps, and possibly the narrow and U‐shaped field of trichomes on the apical part of the galea.     

Cryptic species complexes,widespread species and conservation: lessons from Amazonian frogs of the Leptodactylus marmoratus group (Anura: Leptodactylidae)

Morphologically cryptic species act as a wild card when it comes to biodiversity assessments and conservation, with the capacity to dramatically alter our understanding of the biological landscape at the taxonomic, ecological, biogeographic, evolutionary, and conservation levels. We discuss the potential effects that cryptic species may have on biodiversity assessments and conservation, as well as some of the current issues involving the treatment of cryptic species both at taxonomic and conservation levels. In addition, using a combination of advertisement call and morphological data, we describe a new species of the Leptodactylus marmoratus group from the upper Amazon basin, and we assess how cryptic species can affect conservation assessments of species in the Leptodactylus marmoratus group by examining how recent findings affect our understanding of the distribution of what is assumed to be a widespread Amazonian species, Leptodactylus andreae.     

The larval head morphology of Xyela sp. (Xyelidae, Hymenoptera) and its phylogenetic implications

Larval head structures of Xyela sp. are described in detail. The characters are compared to conditions found in larvae of other groups of Hymenoptera and Endopterygota. Like other symphytan larvae the immature stages of Xyelidae are mainly characterized by presumably plesiomorphic features of the head. The head sutures are well developed and all parts of the tentorium are present. The labrum is free and a complete set of labral muscles is present. The maxillae are in a retracted position. In contrast to other hymenopteran larvae Xyela possesses a clypeofrontal suture, a comparatively long antenna and three well‐developed antennal muscles. Apomorphic features of Xyela are the absence of muscles associated with the salivarium and the complete absence of Musculus craniocardinalis. A clade comprising Orussidae and Apocrita is supported by the unsegmented maxillary and labial palps and the absence of the lacinia. Six potential autapomorphies for the Hymenoptera were revealed: (1) the caudal tentorial apodeme, (2) the bifurcated tendon of Musculus craniomandibularus internus, (3) the lateral lobe of the cardo, (4) the origin of M. tentoriohypopharyngalis from the posterior head capsule, (5) the exceptionally strong prepharyngo‐pharyngeal longitudinal muscle and (6) the longitudinal muscle of the silk press. The maxillolabial complex, the vestigial M. craniocardinalis and a distinctly developed labio‐hypopharyngeal lobe bearing the opening of the salivary duct are potential synapomorphies of Hymenoptera and Mecopterida. The globular, orthognathous head capsule, the modified compound eyes, the occipital furrow and the X‐shaped tentorium are features with unclear polarity shared by Hymenoptera and Mecoptera.     

Functional morphology of Palaeozoic ostracods: phylogenetic implications

Recent discussions of ostracod systematics have focused on soft anatomy, both as seen in extant groups and as recorded by rare examples of special fossil preservation. The position of the fossil Palaeocopina and Leperditicopida, for which no substantial soft part evidence has yet been found, remains in the view of post-Palaeozoic workers uncertain, with some doubt as to whether they should be retained within the Ostracoda. The evolution of carapace bauplans (e.g. the development of brood pouches and lobal structures in palaeocopids as well as the development of adductor muscle scar patterns, calcified inner lamellae and carapace incisures in podocopines) is discussed in relation to presumed soft anatomy. It seems possible to distinguish between plesiomorphic (ancestral, simple) and apomorphic (derived, advanced) characters and consider their significance in ostracod systematics. Although the presumed ‘protostracod’ is not known, the combination of soft anatomy, carapace architecture and behaviour (feeding techniques, brood care) provide evidence of a general body plan which appeared (at the latest) during the Ordovician and continuously evolved towards the anatomy of modern ostracods. In parallel lineages, plesiomorphic forms have died out (leperditicopids and most palaeocopines as well as metacopines), while apomorphic lineages (‘drepanellid archetype’ of palaeocopines; resistant platycopines, podocopines and myodocopines) have survived all extinction events. The evidence supports the retention of the Palaeocopina (and probably the Leperditicopida) in the Ostracoda.     

Comparative morphology of mandibular structures in lycid larvae and its phylogenetic implications (Polyphaga, Hexapoda)

The morphology of the larval mandibular structures of the family Lycidae (Polyphaga) is characterized by facultative dicondyly, posterior articulation with long mandibular rods, lateral location of the anterior condyle and its articulation with a paired non‐cranial structure. It is compared to that of Eucrustacea, Chilopoda, Entognatha, Microcoryphia and Zygentoma and found to be more reminiscent of the Entognatha. The phylogenetic implications of this conclusion are discussed, with the Pterygota and Dicondylia hypothesized to be non‐monophyletic.     

The larval morphology of the spongefly Sisyra nigra (Retzius, 1783) (Neuroptera: Sisyridae)

The morphology of mature larvae of Sisyra nigra was studied and documented with a broad spectrum of techniques. Special emphasis is on the cephalic anatomy and on the digestive tract. Cephalic structures are highly modified, with numerous autapomorphic conditions, including a globular head capsule, an extended area with large cornea lenses, a massive tentorium, a strongly developed prepharyngeal pumping apparatus with a horizontal arrangement of dilators, a sharp bend between the prepharynx and pharynx, and an unusual filter apparatus at the entrance of the large crop. The thoracic and abdominal muscle sets, and the legs are largely unmodified. Postcephalic apomorphies are conspicuous tergal setiferous tubercles, trifid setiferous pleural projections, single pretarsal claws, zigzag-shaped abdominal tracheal gills, and a dense vestiture of setae on the terminal abdominal segments. Mandibulo-maxillary stylets curved outwards are an unusual apomorphy also found in the semiaquatic larvae of Osmylidae. Semiaquatic or aquatic habits and secondarily multisegmented antennae are potential synapomorphies of these two groups and Nevrorthidae (Osmyloidea). A sistergroup relationship between Sisyridae and Nevrorthidae suggests that fully aquatic habits of larvae may be a synapomorphy of both families. A specialized terminal antennal seta is a potential groundplan apomorphy of Neuroptera, with secondary loss in Nevrorthidae and Ithonidae + Myrmeleontiformia, respectively. A trumpet-shaped empodium is likely an apomorphy of Neuroptera excluding Coniopterygidae and Osmyloidea, and the secondary loss an apomorphy of Ithonidae on one hand, and Myrmeleontiformia excl. Psychopsidae on the other.     

Wood anatomy of Penaeaceae (Myrtales): comparative, phylogenetic, and ecological implications

Wood samples of stems, lignotubers, and roots of the majority of species of Penaeaceae were analyzed with respect to qualitative and quantitative features. Virtually no data have hitherto been presented on xylem features of this family, restricted to Cape Province, South Africa. Presence of vestured pits in vessels, septate crystalliferous parenchyma in wood, intraxylary phloem, predominantly erect ray cells in the typically narrow, multiseriate rays and in the uniseriate rays, and amorphous deposits in ray cells place Penaeaceae securely in Myrtales and help to define that order. By comparison of ecological preferences of the species, as observed during field work, with quantitative analysis of conductive tissue, close correspondence of the wood structure to habit and habitat is demonstrated.     

Pollen morphology of the Swertiinae (Gentianaceae): phylogenetic implications

Recent molecular surveys of the Swertiinae (Gentianaceae–Gentianeae) revealed unexpected phylogenetic relationships, including polyphyly of the genera Gentianella , Jaeschkea , Lomatogonium and Swertia . To find new non-molecular characters supporting the phylogeny, we examined the exine variation of 73 species of all major lineages of subtribe Swertiinae using environmental scanning electron miscroscopy supplementing older, mainly light microscopical, studies. In contrast to previous studies, we were able to pick out taxa from phylogenetic key positions with particular focus on Swertia . Many distantly related taxa such as parts of Frasera , Gentianopsis , Halenia , Gentianella , Megacodon and several lineages of Swertia share a striate–reticulate or reticulate exine pattern. This is interpreted as the plesiomorphic character state of Swertiinae. There is also considerable variation of derived patterns; for example, different types of microechinate or almost smooth pollen was repeatedly observed in distantly related groups. Another extreme was the ring-shaped reticulation found in a North American species of Gentianopsis . Unfortunately, major relationships as revealed by molecular analyses were rarely supported because of the abundance of the plesiomorphic type and homoplasy even on low taxonomic levels; for example, within Lomatogonium . Exine variation was particularly useful in characterizing independent lineages of Swertia . For example, according to pollen characters and in agreement with other data, the Asian Swertia cuneata is a sister group of a strongly diversified African lineage and Swertia yunnanensis , which is rather aberrant in flower morphology, seems close to parts of Lomatogonium .  © 2008 The Linnean Society of London, Botanical Journal of the Linnean Society , 2008, 157 , 323–341.     

Chytrid fungus parasitizing the wild amphibian Leptodactylus ocellatus (Anura: Leptodactylidae) in Argentina

The present contribution is the first report of parasitosis by a chytrid fungus in wild anuran amphibians in Argentina, as well as the first case of amphibian mortality documented to date in Argentina. We report the presence of the chytrid fungus in dead adult Leptodactylus ocellatus. It has been suggested that chytridiomycosis is the main cause of death in several amphibian populations worldwide. Our study demonstrates that chytridiomycosis afflicts L. ocellatus, a common widespread amphibian species, and is the first report of chytridiomycosis in the Argentinian lowlands. The occurrence at this latitude would indicate an extended distribution of this fungus in wildlife populations. It is also the first report of amphibian mortality due to chytrid fungus in our country. It is noteworthy that the site of collection is situated very close to sea level in a temperate climate zone and that this represents the southern most record for South American wild amphibians.     

Polygyrid relations: a phylogenetic analysis of 17 subfamilies of land snails (Mollusca: Gastropoda: Stylommatophora)

The family of polygyrid land snails in North America is significant for its sympatric shell convergences, diversity of mating systems and complex zoogeography; its monophyly and its relation to other families has long been questionable. Cladistic analysis has been performed on one representative each of 17 subfamilies, including all three polygyrid subfamilies and one or more subfamilies each from all ten of the families that have been proposed as the polygyrid sister groups. Eighteen anatomical synapomorphies are used, of which eight are newly discovered, four are differently assessed from previous studies, and six are traditional. The resulting strict consensus tree of alternative maximum-parsimony cladograms is: (Acavidae (Ammonitellidae Corillidae ((Discidae Oreohelicidae) (Helminthoglyptidae Bradybaenidae Polygyridae (Thysanophoridae (Camaenidae Sagdidae)))))).
According to this working hypothesis, the Polygyridae are monophyletic, and their sister group remains unresolved, although the Acavidae, Ammonitellidae, Corillidae, Discidae and Oreohelicidae can be ruled out. Of the five classifications of stylommatophoran families that have been proposed in the past 12 years, the consensus tree is closest to that of Nordsieck. For future morphological work, three regions are recommended as potentially rich in unused phylogenetic information: the fertilization pouch-seminal receptacle complex, the ureter at the pneumostome and the ventral-chain ganglia. Simultaneous dissection, wkh side-by-side comparisons, is recommended over other methods for detecting homologies in land snails. Molecular characters should be exploited, because of the scarcity and the frequent homoplasy of morphological characters.     

Ocellatins: New Antimicrobial Peptides from the Skin Secretion of the South American Frog <Emphasis Type="Italic">Leptodactylus ocellatus</Emphasis> (Anura: Leptodactylidae)

The emergence, in recent years, of microbial resistance to commonly used antibiotics has aroused a search for new naturally occurring bactericidal and fungicidal agents that may have clinical utility. In the present study, three new antimicrobial peptides were purified from the electrical-stimulated skin secretion of the South American frog Leptodactylus ocellatus by reversed-phase chromatographic procedures. Ocellatin 1 (¹GVVDILKGAGKDLLAHLVG ISEKV²⁵-CONH²), ocellatin 2 (¹GVVDILKGAGKDLLAHLVGKISEKV²⁵-CONH₂) and ocellatin 3 (¹GVLDILKNAAKNILAHAAEQI²¹-CONH₂) are structurally related peptides. These peptides present hemolytic activity against human erythrocytes and are also active against Escherichia coli. Ocellatins exhibit significant sequence similarity to other amphibian antimicrobial peptides, mainly to brevinin 2ED from Rana esculenta.     

The morphology of neoptile feathers: Ancestral state reconstruction and its phylogenetic implications

Avian neoptile feathers are defined as the first feather generation, which covers the chick after hatching, and usually described as simple structures consisting of numerous downy barbs which are radially symmetrically arranged and come together in a short calamus. In contrast, in some birds (e.g., Anas platyrhynchos, Dromaius novaehollandiae) the neoptile feathers have a prominent rhachis, and therefore display clear bilateral symmetry. Because the symmetrical variety found in neoptile feathers is poorly understood, their morphology was studied in a more comprehensive and phylogenetic approach. Neoptile body feathers from over 22 bird species were investigated using light microscopy, SEM, and MicroCT. Characters such as an anterior–posterior axis, a central rhachis, medullary cells, and structure of the calamus wall were defined and mapped onto recent phylogenetic hypotheses for extant birds. It can be shown that bilaterally symmetric neoptile feathers (with a solid calamus wall) were already present in the stem lineage of crown‐group birds (Neornithes). In contrast, simple radially symmetric neoptile feathers (with a fragile calamus wall) are an apomorphic character complex for the clade Neoaves. The simple morphology of this feather type may be the result of a reduced period of development during embryogenesis. To date, embryogenesis of neoptile feathers from only a few bird species was used as a model to reconstruct feather evolution. Because this study shows that the morphology of neoptile feathers is more diverse and even shows a clear phylogenetic signal, it is necessary to expand the spectrum of “model organisms” to species with bilaterally symmetric neoptile feathers and compare differences in the frequency of feather development from a phylogenetic point of view. J. Morphol., 2011. © 2011 Wiley‐Liss, Inc.     

Chondrocranial, hyobranchial and internal oral morphology in larvae of the basal bufonid genus Melanophryniscus (Amphibia: Anura)

Melanophryniscus is a genus of small toads inhabiting the southern portion of South America. This genus is considered basal within the family Bufonidae. Data on larval chondrocranial morphology do not exist for the genus and larval internal oral anatomy has only been described for a single species. Here, we describe chondrocranial and internal oral morphology in Melanophryniscus montevidensis , M. orejasmirandai and M. sanmartini . Chondrocranial morphology is similar among the species examined. Comparisons with other bufonids and with outgroup taxa suggest that the following chondrocranial characters may represent synapomorphies for the Bufonidae: free (or absent) ceratobranchial IV, a reduced or absent larval crista parotica, the lack of a larval otic process, and late development of thin, poorly chondrified orbital cartilages. The presence of an elongated processus anterior dorsalis of the suprarostral alae and the absence of a chondrified commissura quadratoorbitalis appear to be unique in Melanophryniscus among bufonids. Internal oral anatomy is conserved in Melanophryniscus , and among bufonids in general.