Two new species of the genus Sectonema found in northern Iran are characterized, including morphological descriptions and molecular (18S-, 28S-rDNA) analyses. Sectonema tehranense sp. nov. is distinguished by its 7.22 – 8.53 mm long body, lip region offset by constriction and 24 – 31 μm wide with perioral lobes and abundant setae- or cilia-like projections covering the oral field, mural tooth 15.5 – 17 μm long at its ventral side, neck 1091 – 1478 μm long, pharyngeal expansion occupying 61 – 71% of the total neck length, female genital system diovarian, uterus simple and 3.9 – 4.2 times the corresponding body diameter long, transverse vulva (V = 49 – 59), tail short and rounded (44 – 65 μm, c = 99 – 162, c’ = 0.6 – 0.8), spicules 111 – 127 μm long, and 7 – 10 spaced ventromedian supplements with hiatus. Sectonema noshahrense sp. nov. displays a 4.07 – 4.73 mm long body, lip region offset by constriction and 23 – 25 μm wide with perioral lobes and abundant setae- or cilia-like projections covering the oral field, odontostyle 14 – 14.5 μm long, neck 722 – 822 μm long, pharyngeal expansion occupying 66 – 68% of the total neck length, female genital system diovarian, uterus simple and 2.4 – 2.7 times the corresponding body diameter long, transverse vulva (V = 54 – 55), tail convex conoid (39 – 47 μm, c = 91 – 111, c’ = 0.8 – 0.9), spicules 82 μm long, and seven spaced ventromedian supplements with hiatus. Molecular analyses confirm a maximally supported (Epacrolaimus + Metaporcelaimus + Sectonema) clade and a tentative biogeographical pattern, with sequences of Indolamayan taxa forming a clade separated from those of Palearctic ones. Parallel or convergent evolution processes might be involved in the phylogeny of the species currently classified under Sectonema. This genus is certainly more heterogeneous than previously assumed.

A new species of the free-living nematode genus Trachactinolaimus, collected in natural habitats of northern Iran, is described, including morphological and molecular (28S-rDNA) data. Trachactinolaimus persicus sp. n. is characterized by its 1.95–2.44 mm long body, lip region weakly offset by depression and 18–20 μm wide, odontostyle 25–27 μm long, neck 540–636 μm long, pharyngeal expansion occupying one-half of the total neck length, bipartite uterus 2.6–3.9 body diameters long, vulva (V = 49–53) pore-like, tail long and filiform in both sexes (174–223 μm, c = 10.0–13.4, c’ = 5.9–7.0 in females, 165–196 μm, c = 10.7–13.8, c’ = 4.6–5.8 in males), spicules 68–75 μm long, and 12–14 almost contiguous ventromedian supplements with hiatus. Molecular data supports the monophyly of the genus and the hypothesis that Dorylaimidae are the sister group of actinolaims. The taxonomy of Trachactinolaimus is updated, including diagnosis, list of species, key to their identification, and a compendium of their main morphometrics. Dominiactinolaimus is regarded as its junior synonym.

The evolutionary relationships of the nematode genus Loofilaimus are explored with an integrative approach, combining morphological and molecular (28S-rDNA) data. Never recorded since its original description in 1998, the finding of fresh specimens of its type and only species, L. phialistoma, allowed us to obtain SEM observations and sequencing, both for the first time, resulting in relevant aspects to elucidate its phylogeny. Morphologically, the genus is characterized by two autapomorphies affecting its lip region and pharynx. Molecular study revealed that it represents a very restricted evolutionary trend within Dorylaimida. The clade (Nygolaimina + (Loofilaimus + Dorylaimina)) is well supported. Loofilaimidae is accepted as a separate and valid family, which should also include Bertzuckermania.

Elsewhere I have proposed a set of rules according to which we may categorise Germanic root nouns into three chronological layers. In this article, I present a synchronic classification of all of the Elfdalian actual and potential root-noun continuants as well as their etymologies and derivational histories in light of this proposal and in order to reveal (i) some interesting aspects of the general processes involved in shifts of inflectional class, and (ii) whether or not some of these processes in Elfdalian when compared to other Nordic varieties may shed light on the cladistical status of Elfdalian within North Germanic. The analysis shows that, while those Elfdalian root-noun continuants whose ancestral forms belong to layers I, IIa and IIb generally remain stable and keep their appurtenance to the root-noun inflectional class, some of the (non-)root-noun continuants actually and potentially belonging to layer III deserve additional attention with regard to this twofold aim.

Specimen-level phylogenetic approaches are widely used in molecular biology for taxonomic and systematic purposes. However, they have been largely ignored in analyses based on morphological traits, where phylogeneticists mostly resort to species-level analyses. Recently, a number of specimen-level studies have been published in vertebrate palaeontology. These studies indicate that specimen-level phylogeny may be a very useful tool for systematic reassessments at low taxonomic levels. Herein, we review the challenges when working with individual organisms as operational taxonomic units in a palaeontological context, and propose guidelines of how best to perform a specimen-level phylogenetic analysis using the maximum parsimony criterion. Given that no single methodology appears to be perfectly suited to resolve relationships among individuals, and that different taxa probably require different approaches to assess their systematics, we advocate the use of a number of methodologies. In particular, we recommend the inclusion of as many specimens and characters as feasible, and the analysis of relationships using an extended implied weighting approach with different downweighting functions. Resulting polytomies should be explored using a posteriori pruning of unstable specimens, and conflicting tree topologies between different iterations of the analysis should be evaluated by a combination of support values such as jackknifing and symmetric resampling. Species delimitation should be consistent among the ingroup and based on a reproducible approach. Although time-consuming and methodologically challenging, specimen-level phylogenetic analysis is a highly useful tool to assess intraspecific variability and provide the basis for a more informed and accurate creation of species-level operational taxonomic units in large-scale systematic studies. It also has the potential to inform us about past speciation processes, morphological trait evolution, and their potential intrinsic and extrinsic drivers in pre-eminent detail.

Amongst the Hexactinellida, Hexasterophora is the most important taxon in terms of number of species as well as concerning the variability in morphological characters. In this study the first comprehensive analysis of phylogenetic relations between hexactinellid families and genera of the subclass Hexasterophora based on morphological features is presented. Therefore, 157 morphological characters of the Hexasterophora were compiled into a matrix by presence/absence data. The resulting phylogenetic trees are compared with conclusions based on molecular data and classical systematics. So far, we find the main hexasterophoran taxa (Hexactinosida, Rossellidae and Euplectellidae) well established as monophyletic and in rather good correspondence with classical systematics and molecular results. Our phylogenetic trees largely support the systematic classification proposed by Schulze (1886) and Mehl (2002). However, some families (e.g. Euretidae) are not corroborated. For others (Euplectellidae), our cladistics approach is at odds with the system proposed by Tabachnick (2002a). Morphological phylogeny becomes problematic for those taxa, in which many of the diagnostic characters are either symplesiomorphic, or multiple homoplastic. Our results indicated the need for revision of the classification features used.

Three new freshwater ameirid species were discovered in the Western Australian subterranean habitats and described in this paper. They all proved to belong to the genus Nitocrellopsis Galassi, De Laurentiis & Dole-Olivier, 1999, representing the first record of this genus in Australia. Nitocrellopsis operculata sp. nov. was collected in 2003 in the Pilbara region, during the Pilbara Regional Survey, led by the Western Australian Department of Environment and Conservation (DEC). It can be distinguished from all other congeners by the reduced armature of the antennal exopod, which is an autapomorphic feature. Also, no other species of Nitocrellopsis has cuticular windows on prosomal or urosomal somites, or six elements on the third exopodal segment of the second leg. Nitocrellopsis halsei sp. nov. and N. pinderi sp. nov. are sister-species, collected in 2007 in the neighbouring Yilgarn region, by the private environmental consulting company Bennelongia Pty Ltd. Numerous morphological similarities include somite ornamentation, armature patterns of the swimming legs and the fifth leg, as well as the shape and armature of the antennula, antenna and almost all mouth appendages, while the main differences between the two are observed in the body size and habitus appearance, caudal rami shape and size, presence/absence of large lateral pores on the fourth pedigerous somite, number of spinules on the anal operculum, number of setae on the madibular endopod, and shape of the exopod of the fifth leg. Although they differ from any other congener by a combination of characters, no significant autapomorphic features were observed. In order to find a more natural allocation of these three species, a cladistic analysis is performed on all current members of Nitocrellopsis and three outgroup taxa, based on 45 morphological characters. The resulting cladogram shows that the ingroup is well defined by at least four synapomorphies, but the Australian species from the two regions are only remotely related to each other, showing the importance of looking at small-scale patterns when inferring Gondwanan biogeography. Three sister-species pairs are recognized in the genus and a key to all 12 members is provided.

Ornithischia is a familiar and diverse clade of dinosaurs whose global phylogeny has remained largely unaltered since early cladistic analyses in the mid 1980s. Current understanding of ornithischian evolution is hampered by a paucity of explicitly numerical phylogenetic analyses that consider the entire clade. As a result, it is difficult to assess the robustness of current phylogenetic hypotheses for Ornithischia and the effect that the addition of new taxa or characters is likely to have on the overall topology of the clade.

The new phylogenetic analysis presented here incorporates a range of new basal taxa and characters in an attempt to rigorously test global ornithischian phylogeny. Parsimony analysis is carried out with 46 taxa and 221 characters. Although the strict component consensus tree shows poor resolution in a number of areas, application of reduced consensus methods provides a well-resolved picture of ornithischian interrelationships. Surprisingly, Heterodontosauridae is placed as the most basal group of all well-known ornithischians, phylogenetically distant from a stem-defined Ornithopoda, creating a topology that is more congruent with the known ornithischian stratigraphical record. There is no evidence for a monophyletic ‘Fabrosauridae’, and Lesothosaurus (the best-known ‘fabrosaur’) occupies an unusual position as the most basal member of Thyreophora. Other relationships within Thyreophora remain largely stable. The primitive thyreophoran Scelidosaurus is the sister taxon of Eurypoda (stegosaurs and ankylosaurs), rather than a basal ankylosaur as implied by some previous studies.

The taxonomic content of Ornithopoda differs significantly from previous analyses and basal relationships within the clade are weakly supported, requiring further investigation. ‘Hypsilophodontidae’ is paraphyletic, with some taxa (Agilisaurus, Hexinlusaurus, Othnielia) placed outside of Ornithopoda as non-cerapodans. Ceratopsia and Pachycephalosauria are monophyletic and are united as Marginocephalia; however, the stability of these clades is reduced by a number of poorly preserved basal taxa.

This analysis reaffirms much of the currently accepted ornithischian topology. Nevertheless, instability in the position and content of several clades (notably Heterodontosauridae and Ornithopoda) indicates that considerable future work on ornithischian phylogeny is required and causes problems for several current phylogenetic definitions.

Brain evolution is a complex weave of species similarities and differences, bound by diverse rules and principles. This book is a detailed examination of these principles, using data from a wide array of vertebrates but minimizing technical details and terminology. It is written for advanced undergraduates, graduate students, and more senior scientists who already know something about “the brain,” but want a deeper understanding of how diverse brains evolved. The book's central theme is that evolutionary changes in absolute brain size tend to correlate with many other aspects of brain structure and function, including the proportional size of individual brain regions, their complexity, and their neuronal connections. To explain these correlations, the book delves into rules of brain development and asks how changes in brain structure impact function and behavior. Two chapters focus specifically on how mammal brains diverged from other brains and how Homo sapiens evolved a very large and “special” brain.

Criticisms by Kriwet regarding recent work on pycnodont phylogeny are based on the use of additive characters. Therefore, applying transformation series in phylogenetic reconstruction is justified in theory and in practice, and an example of additional ontogenetic evidence supporting character ordering in pycnodonts is provided. Moreover, comments on some pycnodont genera are included, and the accurate taxonomic use of the genera Coelodus and Ocloedus is emphasised.

Cladistic analysis of the Middle Jurassic ammonite radiation shows how the Aalenian-age ancestral stock, known variously as the Hammatocerataceae or Hammatoceratinae, gave rise to numerous new groups in Bajocian times. Cladistic analysis shows this ancestral stock is not a single lineage but two: the ‘Erycites group’, which gave rise to the Stephanocerataceae, and the ‘Hammatoceras group’, from which all other Bajocian groups derived.

Study of abundant phalangiotarbid (Arachnida: Phalangiotarbida) material – provisionally assigned here to Bornatarbus mayasii (Haupt in Nindel 1955) – from the Upper Carboniferous of Writhlington, UK, has revealed new information about some previously equivocal characters. The present authors report a trifurcate apotele, possible spiracles on sternite 5, and confirm the presence of 10 opisthosomal tergites plus a dorsal anal operculum. The affinities of phalangiotarbids are obscure, with most authors favouring affinities with Opiliones (harvestmen) and/or Acari (mites and ticks). Phalangiotarbida is scored for characters used in previous studies of arachnid relationships. A cladistic analysis based on 63 characters using 13 terminal arachnid taxa (plus a hypothetical outgroup), resolves Phalangiotarbida as sister group to (Palpigradi + Tetrapulmonata): the taxon Megoperculata sensu Shultz (1990). Even under cladistic analysis, the position of the Phalangiotarbida remains hard to resolve, but a prosomal sternite with distinct sclerites potentially groups them with the Megoperculata.

A new hypothesis of the relationships between arachnomorph arthropods, and the origin of chelicerates, is presented based on a cladistic analysis of 34 taxa and 54 characters. The present study provides a detailed discussion of primary hypotheses of homology and includes a more complete range of terminal taxa than previous analyses. The analysis provides the first convincing synapomorphies for the Arachnomorpha, and suggests that the marrellomorphs are not arachnomorphs. The assignment of Cambrian ‘great appendage’ (or megacheiran) arthropods to the Arachnomorpha is confirmed, and potential synapomorphies uniting them with chelicerates are discussed and tested. Principal amongst these are the loss of the first cephalic appendages (the antennae), loss of the exopods of the second cephalic appendages and modification of the endopods of these appendages into spinose grasping organs. The Arachnomorpha consists of two major clades: (1) a ‘chelicerate-allied’ clade, including chelicerates, megacheirans, Emeraldella, Sidneyia, cheloniellids and aglaspidids, in which chelicerates and a paraphyletic group of megacherian arthropods form the sister group to the remaining taxa; and; (2) a ‘trilobite-allied’ clade, including trilobites, xandarellids, helmetiids, tegopeltids and naraoiids, the relationships of which are more fully resolved than in previous studies.

The phylogeny of representative haemozoan species of the phylum Apicomplexa was reconstructed by cladistic analyses of ultrastructural and life-cycle characteristics. The analysis incorporated 4 apicomplexans previously not included in phylogenetic reconstructions: Haemogregarina clelandi from the Brisbane River tortoise (Emydura signata), Hepatozoon sp. from the slaty grey snake (Stegonotus cucullatus), Hepatozoon (Haemogregarina) boigae from the brown tree snake (Boiga irregularis), and Haemoproteus chelodina from the saw-shelled tortoise (Elseya latisternum). There was no apparent correlation between parasite phylogeny and that of their vertebrate hosts, but there appeared to be some relationship between parasites and their intermediate hosts, suggestive of parasite/vector co-evolution.

Morphological classification of snail shells is sometimes arbitrary and misleading in correct species delimitation. This topic is investigated in four nominal species of the minute gastropods of the genus Vallonia (V. pulchella, V. excentrica, V. costata and V. enniensis). First, individuals are classified according to their shell morphology. Second, variation in ribosomal internal transcribed spacer 1 DNA (ITS-1 rDNA) is analysed. Using a cladistic approach, the nucleotide positions of the ITS-1 are elucidated on apomorphic and plesiomorphic character states (outgroup=Acanthinula aculeata; Valloniidae). The molecular data yield evidence that the morphospecies V. excentrica is a paraphyletic group, comprising just a loose arrangement of individuals with similar shells. Data on fossil shells and putative divergence time are also elucidated. In the monograph on Vallonia it has been suggested that the split between the branch of V. costata and the branch of V. pulchella, V. excentrica and V. enniensis could have been in the upper Cretaceous. Based on the ITS-1 sequence alignment and the number of variable nucleotide positions, it is suggested that the last common ancestor of both branches lived at some time during the Miocene or even the Pliocene. Therefore, the fossil stem lines of Vallonia should be newly interpreted.