Studies of fossil hyaenas: the genera Thalassictis Gervais ex Nordmann, Palhyaena Gervais, Hyaenictitherium Kretzoi, Lycyaena Hensel and Palinhyaena Qiu, Huang & Guo

Samples of the Chinese upper Mioeene hyaenids Thalassictis wongii (Zdansky), Thalassictis hyaenoides (Zdansky) and Palinhyaena reperta Qiu, Huang & Guo are analysed and characterized statistically. The generic and specific designations above are considered correct. Using these samples as a basis, the taxonomic status of similar forms from Eurasia is evaluated. Lycyaena is considered a subgenus of Thalassictis and includes the species T. (L.) dubia (Zdansky), T. (L.) chaeretis (Gaudry), T. (L.) macrostoma (Lydekker), and T. (L.) crusafonti (Kurtén). 'Lycyaena' proava Pilgrim and 'L.' chinjiensis Pilgrim are removed from this subgenus. The type specimen of Palhyaena hipparionum (Gervais) is missing and cannot be determined to genus on the basis of published information. Most other forms are referred to Thalassictis (Thalassictis) , except 'Ictitherium' sivalense Lydekker, which is considered to be closely related to Palinhyaena .     

Monophily and pollination mechanisms in Angraecum arachnites Schltr. (Orchidaceae) in a guild of long-tongued hawk-moths (Sphingidae) in Madagascar

Anthecological relations between a long-spurred angraecoid orchid and pollinating Sphingidae are documented for the first time. In a primary forest on the Central Plateau of Madagascar Angraecum arachnites Schltr. was found to be pollinated by and adapted to a single species of hawk-moth, Panogena lingens (Butler), despite abundance of many concurrent Sphingidae of which several were also long-tongued. Furthermore, P. lingens was dimorphic in the length and breadth of its proboscis and only the morph with the longest and most slender proboscis was recorded to pollinate A. arachnites . Exclusive and precise adaptation to the latter morph of P. lingens existed in floral morphology and probably in other characteristics such as flowering phenology and chemical signalling. Several concurrently flowering orchid species were sharing P. lingens as a pollinator resource. The monophily in A. arachnites is interpreted as a result of a refined long-term specialization developed within an archaic evolutionary relationship in a relatively stable environment. The extraordinary number and diversity of long-spurred Orchidaceae in Madagascar appears to be a direct coevolutionary consequence of an Old-World-unique diversity of long-tongued archaic Sphingidae that has persisted in this isolated land.     

Preservational folds simulating tergite junctions in tegopeltid and naraoiid arthropods

The exoskeleton in the Middle Cambrian Burgess Shale arthropod Tegopelte has previously been described as divided into tergites. Evidence from its sister taxon Saperion and from a Naraoia specimen from the Lower Cambrian Chengjiang fauna enables a reinterpretation of the suggested tergite boundaries in Tegopelte as preservational artefacts. They are considered here as folds that were formed during flattening of the undivided dorsal shield. As in the Naraoia specimen, the folds were initiated in the axial region between appendage pairs and then continue laterally. In Tegopelte and Saperion , segmentally arranged furrows in the axial region facilitated fold formation. Characters other than presence of thoracic tergites and pygidium must be used to assess the affinities of Tegopelte, Arthropoda, Tegopeltidae, tagmosis, segmentation, Chengjiang fauna, Burgess Shale.     

Evolutionary history of a secondary terrestrial Australian diving beetle (Coleoptera,Dytiscidae) reveals a lineage of high morphological and ecological plasticity

The evolution of a secondary terrestrial lifestyle in diving beetles (Coleoptera: Dytiscidae) has never been analysed in a phylogenetic framework before. Here we study Terradessus caecus Watts, a terrestrial species of the subfamily Hydroporinae endemic to Australia. We infer its phylogenetic placement using Bayesian inference and maximum‐likelihood methods based on a multilocus molecular dataset. We also investigate the divergence time estimates of this lineage using a Bayesian relaxed clock approach. Finally, we infer ancestral ecological preferences using a likelihood approach. We recover T. caecus nested in the genus Paroster Sharp with strong support. Therefore, we establish a synonymy for both species of Terradessus with Paroster: Paroster caecus (Watts) n.comb . and Paroster anophthalmus (Brancucci & Monteith) n.comb . Paroster is an endemic Australian genus that has a remarkable number of subterranean species in underground aquifers with highly derived morphologies. Our results highlight one of the most remarkable radiations of aquatic beetles with independent ecological pathways likely linked to palaeoclimatic disruptions in the Neogene. Paroster caecus (Watts) n.comb . originated from a mid‐Miocene split following the onset of an aridification episode that has been ongoing to the present day. The deep changes in ecological communities in association with the drying‐out of palaeodrainage systems might have pushed this lineage to colonize a new niche in terrestrial habitats.     

A peculiar climbing Megalonychidae from the Pleistocene of Peru and its implication for sloth history

The Xenarthra, particularly the Tardigrada, are with the Notoungulata and Marsupialia among the most diversified South American mammals. Lujanian South American Land Mammal Age localities from the coastal Piedra Escrita site and Andean Casa del Diablo Cave, Peru, have yielded three specimens of the Megalonychidae Diabolotherium nordenskioldi gen. nov. This singular fossil sloth exhibits a peculiar mosaic of cranial and postcranial characters. Some are considered convergent with those of other sloths (e.g. 5/4 quadrangular teeth, characteristic of Megatheriidae), whereas others clearly indicate climbing capabilities distinct from the suspensory mode of extant sloths. The arboreal mode of life of D. nordenskioldi is suggested by considerable mobility of the elbow, hip, and ankle joints, a posteriorly convex ulna with an olecranon shorter than in fossorial taxa, a radial notch that faces more anteriorly than in other fossil sloths and forms an obtuse angle with the coronoid process (which increases the range of pronation–supination), a proximodistally compressed scaphoid, and a wide range of digital flexion. D. nordenskioldi underscores the great adaptability of Tardigrada: an arboreally adapted form is now added to the already known terrestrial, subarboreal, and aquatic (marine and freshwater) fossil sloths. A preliminary phylogenetic analysis of the Tardigrada confirmed the monophyly of Megatherioidea, Nothrotheriidae, Megatheriidae, and Megalonychidae, in which Diabolotherium is strongly nested.  © 2007 The Linnean Society of London, Zoological Journal of the Linnean Society , 2007, 149 , 179–235.     

Past and present diversity and distribution in the parasitic wasp family Megalyridae (Hymenoptera)

The phylogenetic relationships of extant and extinct Megalyridae are analysed at the genus level. The dataset comprises seven outgroup taxa, all eight extant genera and a number of extinct taxa that have been associated with Megalyridae, including two genera from Maimetshidae, whose affinity with Megalyridae is uncertain. Analytical results are unstable because some of the fossil taxa have many missing entries. The most stable results are produced when the maimetshid taxa and Cretodinapsis are excluded. When included, these taxa fall outside crown‐group Megalyridae, the maimetshid taxa being the sister of Orthogonalys (Trigonalidae). Based on the results of our analyses, we synonymize the fossil genera Rubes Perrichot n.syn . and Ukrainosa Perrichot & Perkovsky n.syn . with Prodinapsis, creating the new combinations Prodinapsis bruesi n.comb . and Prodinapsis prolata n.comb . When comparing past and present distributions of Megalyridae with the results of the phylogenetic analyses, it is evident that the genera radiated in the Mesozoic, and that the family as a whole was much more widespread then. The present‐day distribution is essentially relictual, with range contraction since the early Tertiary probably being the result of climate deterioration, which caused the disappearance of tropical forests throughout the Palaearctic.     

Chemical Properties and Physiological Actions of Crustacean Chromatophorotropins

The crustacean pigment-translocating hormones, the red pigment-concentratinghormone (RPCH), an octapeptide, and the light-adapting distalretinal pigment hormone (DRPH), an octadecapeptide, are thefirst invertebrate neurohormones to be fully characterized.Studies with both purified and synthetic hormones show that,in certain decapods, RPCH is a general pigment-concentratinghormone (PCH), affecting the pigments of all kinds of chromatophores(erythrophores, xanthophores, leucophores and melanophores);the DRPH seems to serve not only light-adapting function, butalso act as a general chromatophore pigment-dispersing hormone(PDH). The two hormones thus function as antagonists when regulatingthe color-adaptation of the decapod crustaceans. PCH activityis widely distributed within the arthropod endocrine systems.The first characterized insect neurohormones, the locust adipokinetichormones (AKH I and AKH II), show close structural similaritiesto the crustacean hormone, indicating a common evolution ofsome of the arthropod neurohormones. Physiological studies ofthe three hormones (RPCH, AKH I, and AKH II) and their syntheticanalogs show that they crossreact, i.e., they all exhibit pigment-concentratingactivity when tested on decapod crustaceans, adipokinetic activitywhen tested on locusts, and hyperglycemic activity when testedon cockroaches, although each of the hormones is more potentin its own system. Structure-function studies show, however,that quite different binding-site requirements exist for thehormones in activating their receptors on the various targettissues. The physiological specificity in their action thereforeseems to depend on a differential evolution of the hormone receptors.     

Studies of fossil hyaenids: the genera Hyaenictis Gaudry and Chasmaporthetes Hay, with a reconsideration of the Hyaenidae of Langebaanweg, South Africa

The fossil hyaenids from Langebaanweg in South Africa are revised taxonomically using both morphological comparisons and measurement data. Ictilherium preforfex is found to be a synonym of Ikelohyaena abronia . Other hyaenid taxa in this fauna are Hyaenictitherium namaquensis, Chasmaporthetes australis and a new taxon similar to Chasmaporthetes australis in the size and shape of the M₁, trigonid and other characters, but differing from this taxon in having short P₃ relative to P₂, a smaller anterior accessory cusp on P₄ and M₂, present. This taxon has previously been referred to Euryboas sp***, but comparison with Eurasian hyaenids indicates that it shares diagnostic characters with Hyaenictis graeca , type species of the genus Hyaenictis . This genus is poorly known and its content is reviewed. We find that only the new species from Langebaanweg, formally described as Hyaenictis hendeyi sp. nov. , and the Spanish Hyaenictis almerai probably belong in this genus, while other taxa intermittently referred to Hyaenictis belong to other genera. Thus, neither Leecyaena bosei nor Chasmaporthetes silberbergi belong in Hyaenictis .