Evolution of Strigamia centipedes (Chilopoda): a first molecular assessment of phylogeny and divergence times

We present a first phylogenetic and temporal framework, with biogeographical insights, for the centipedes of the genus Strigamia, which are widespread predators in the forest soils of the Northern Hemisphere and comprise the evo-devo model species Strigamia maritima. The phylogeny was estimated by different methods of maximum likelihood and Bayesian inference from sequences of two mitochondrial (16S, COI) and two nuclear (18S, 28S) genes, obtained from 16 species from all major areas of the global range of the genus and encompassing most of the overall morphological and ecological diversity. Divergence times were estimated after calibration upon the fossil record of centipedes. We found that major lineages of extant species of Strigamia separated most probably around 60 million years (Ma) ago. The two most diverse lineages diversified during the last 30 Ma and are today segregated geographically, one in Europe and another in Eastern Asia. This latter region hosts a hitherto underestimated richness and anatomical diversity of species, including three still unknown, yet morphologically well distinct species, which are here described as new: Strigamia inthanoni sp. n. from Thailand, Strigamia korsosi sp. n. from the Ryukyu Islands and Strigamia nana sp. n. from Taiwan. The northern European model species S. maritima is more strictly related to the Eastern Asian lineage, from which it most probably separated around 35 Ma ago before the major diversification of the latter

Assessing troglomorphic and phylogenetically informative traits in troglobionts: a new cave-dwelling centipede illuminates the evolution of a soil-dwelling lineage (Chilopoda: Geophilidae)

Cave-dwelling species are of special interest in evolutionary biology, because (i) many share particular traits associated with the cave habitat (troglomorphic traits), and (ii) some represent relict lineages that may conserve ancestral traits or possibly transitional traits, which may provide insights into the evolution of other highly derived species. However, these different kinds of characters are hard to assess thoroughly in troglobionts belonging to little known terrestrial arthropod groups. We describe a new species of centipedes from the Areias System caves, Brazil, namely, Plutogeophilus jurupariquibaba gen.n. sp.n., which adds to the few putative troglobionts known among Chilopoda Geophilomorpha. We analyzed a suite of characters in the light of a phylogenetic analysis and by direct comparison with epigean relatives, controlling for interindividual variation and its confounding sources. We found that: (i) troglomorphic traits of P. jurupariquibaba may include large body, elongate antennae, elongate legs and claws, and possibly also elongate setae and large coxal pores; (ii) the cave-dwelling Plutogeophilus is the sister lineage of the soil-dwelling Macronicophilus, whose morphology is highly derived and whose phylogenetic position remained unclear; (iii) compared with other extant geophilids, symplesiomorphic traits and apparently intermediate traits found in Plutogeophilus provide insights on the origin of the morphology of Macronicophilus, suggesting a stepwise modification of labrum, forcipular apparatus and ultimate legs, and the derivation of the unique rounded and spiny tip of the second maxillae from a pointed claw

The phylogenetic position of <i>Dinogeophilus</i> and a new evolutionary framework for the smallest epimorphic centipedes (Chilopoda: Epimorpha)

The centipedes of the clade Epimorpha change slightly during post-embryonic growth but there is huge variation between species in the maximum body size. New specimens of the rarely collected Neotropical genus Dinogeophilus provide further evidence that this genus comprises the smallest species of the Epimorpha, with a recorded maximum length of 5.5 mm. Up to now Dinogeophilus has been invariantly classified in Geophilidae but different sources of evidence (examination by SEM, cladistic evaluation of morphology, similarity and phylogenetic analysis of molecular data) agree on a very different phylogenetic hypothesis: Dinogeophilus is actually a derived lineage of Schendylidae, only distantly related to Geophilidae, and possibly belong to a mainly Neotropical subgroup of schendylids. A comparison of Dinogeophilus with the most closely related taxa suggests that body miniaturization was accompanied by possibly paedomorphic traits, including lower number of some multiple elements (antennal sensilla, processes on the mouth-parts, coxal organs) and shorter setae. Possibly associated with miniaturization are also a few novel features of Dinogeophilus, among which the unique subterminal denticles of the forcipules, suggesting a possible change in the feeding behaviour.Facultad de Ciencias Naturales y Muse

A common terminology for the external anatomy of centipedes (Chilopoda)

A common terminology for the external morphological characters of centipedes (Chilopoda) is proposed. Terms are selected from the alternatives used in the English literature, preferring those most frequently used or those that have been introduced explicitly. A total of 330 terms are defi ned and illustrated, and another ca. 500 alternatives are listed.Facultad de Ciencias Naturales y Muse

Pushing Taxonomy to Extiction?

Can we describe all species on Earth before they disappear? We argue that this is possible only by endowing taxonomy with professional manpower and appropriate material resources as required by big science. Contrary to Costello et al.’s (CMS) (1) statements, taxonomy is not an easy discipline accessible to all through a smartphone. It requires exhaustive training and long familiarity with field, specimens and literature (2). CMS’s argument is framed in terms of species numbers, but different, non-overlapping species concepts apply to bacteria, brambles and birds (3,4,5): “the species” as common unit of biodiversity does not exist (6). Even ignoring this conceptual and semantic issue, CMS’s estimates of undescribed biodiversity and extinction rates are based on insufficient evidence and poorly supported models. Biodiversity hotspots steadily emerge in geographic areas where diversity was long assumed to be largely described (7,8). The number of species, whatever species are, cannot be easily estimated because of the historical, rather than deterministic or teleological, nature of biological evolution (9,10). Extinction rates are highly context-sensitive (11), lineage- and region-dependant, thus generally difficult to ascertain (12) without thorough analyses of data such as IUCN’s estimates of threats and extinctions (13). However, evidence being mainly restricted to vertebrates, the extinction risks in most other groups remain terra incognita. Furthermore, recent surveys (14,15) do not support CMS’s optimistic predictions regarding extinction rates. CMS’s agenda emphasizes technology, voluntary work and recognition of subjective “morphospecies” (16). However, improvement of data storage and retrieval cannot substitute for the production of sound data. Serious taxonomists cannot describe two new species per week, as suggested by CMS’s calculations. Describing new species, even with the help of molecular data and especially in best-investigated groups, is increasingly demanding, following the “law of diminishing returns” (17). More than anything else, taxonomy requires professional manpower, unrestricted fieldwork and permanent collections

Single and coupled L3 photonic crystal cavities for cavity-QED experiments

Here we discuss the experimental characterization of the spatial far-field profiles for the confined modes in a photonic crystal cavity of the L3 type, finding a good agreement with FDTD simulations. We then link the far-field profiles to relevant features of the cavity mode near-fields, using a simple Fabry-Perot resonator model. Finally, we describe a technique for independent all-electrical control of the wavelength of quantum dots in separated L3 cavities, coupled by a waveguide, by electrical isolation via proton implantation

A common terminology for the external anatomy of centipedes (Chilopoda)

A common terminology for the external morphological characters of centipedes (Chilopoda) is proposed. Terms are selected from the alternatives used in the English literature, preferring those most frequently used or those that have been introduced explicitly. A total of 330 terms are defi ned and illustrated, and another ca. 500 alternatives are listed.Facultad de Ciencias Naturales y Muse

Far-field emission profiles from L3 photonic crystal cavity modes

We experimentally characterize the spatial far-field emission profiles for the two lowest confined modes of a photonic crystal cavity of the L3 type, finding a good agreement with FDTD simulations. We then link the far-field profiles to relevant features of the cavity mode near-fields, using a simple Fabry-Perot resonator model. The effect of disorder on far-field cavity profiles is clarified through comparison between experiments and simulations. These results can be useful for emission engineering from active centers embedded in the cavity.Comment: 9 pages, 7 figure