Journal Articles: 2005-2000

Giribet, G. 2005. “Generating implied alignments under direct optimization using POY..” Cladistics 21: 396-402.
Sharma, P, and G Giribet. 2005. “A new Troglosiro species (Opiliones, Cyphophthalmi, Troglosironidae) from New Caledonia. .” Zootaxa 1053: 47-60.
Worsaae, K, A Nygren, GW Rouse, G Giribet, J Persson, P Sundberg, and F Pleijel. 2005. “Phylogenetic position of the meiofaunal family Nerillidae (Annelida: Polychaeta) analyzed by direct optimization of combined molecular and morphological datasets..” Zoologica Scripta 34: 313-328.
Schulze, A, EB Cutler, and G Giribet. 2005. “Reconstructing the phylogeny of the Sipuncula. .” Hydrobiologia 535/536: 277-296.
Schwendinger, PJ, and G Giribet. 2005. “The systematics of the south-east Asian genus Fangensis Ramble (Opiliones: Cyphophthalmi: Stylocellidae).” Invertrabrate Systematics 19: 297-323.
Giribet, G., and J. A. Dunlop. 2005. “First identifiable Mesozoic harvestman (Opiliones: Dyspnoi) from Cretaceous Burmese amber.” Proc Biol Sci 272: 1007-13.Abstract

Two inclusions in a piece of Upper Cretaceous (Albian) Burmese amber from Myanmar are described as a harvestman (Arachnida: Opiliones), Halitherses grimaldii new genus and species. The first Mesozoic harvestman to be named can be referred to the suborder Dyspnoi for the following reasons: prosoma divided into two regions, the posterior formed by the fusion of the meso- and metapeltidium; palp lacking a terminal claw, with clavate setae, and tarsus considerably shorter than the tibia. The bilobed, anteriorly projecting ocular tubercle is reminiscent of that of ortholasmatine nemastomatids. The status of other Mesozoic fossils referred to Opiliones is briefly reviewed.

Boyer, S.L., I. Karaman, and G. Giribet. 2005. “The genus Cyphophthalmus (Arachnida, Opiliones, Cyphophthalmi) in Europe: a phylogenetic approach to Balkan Peninsula biogeography.” Mol Phylogenet Evol 36: 554-67.Abstract

In this study, we present phylogenetic data to characterize the relationships among sironids centered in the Balkan region, and use these results to discuss biogeographical aspects of sironid evolution. Analysis of ca. 4.5 kb of sequence data from three nuclear and two mitochondrial genes reveals monophyly of a Balkan clade for which we resurrect the name Cyphophthalmus, considered a junior synonym of Siro for over a century. This clade diversified into several groups, and at least three of them--the duricorius group, the serbicus group, and the minutus group--are well corroborated by the data as monophyletic lineages. The members of the different groups, mostly living in troglobitic environments, have diversified in overlapping geographic regions, with evidence of an eastern origin for the group. Our data also suggest that mitochondrial and nuclear genes are all contributing towards the final resolution of the combined analysis of the data.

Obst, M., P. Funch, and G. Giribet. 2005. “Hidden diversity and host specificity in cycliophorans: a phylogeographic analysis along the North Atlantic and Mediterranean Sea.” Mol Ecol 14: 4427-40.Abstract

In order to elucidate the evolutionary history and the population structure of the members of the phylum Cycliophora, which live commensally on three species of lobsters, we studied sequence variation in the mitochondrial gene cyctochrome c oxidase subunit I. Overall 242 sequences from 16 locations on both coasts of the North Atlantic, including the North Sea and the Mediterranean, were analysed, revealing 28 haplotypes, with a maximum sequence divergence of 16.6%. Total genetic diversity was high (h = 0.8322, pi = 0.0898), as it was for the commensals on Homarus americanus (17 haplotypes, h = 0.7506, pi = 0.0504). However, it was low for commensals on Nephrops norvegicus (6 haplotypes, h = 0.3899, pi = 0.0035), and intermediate for cycliophorans on Homarus gammarus (5 haplotypes, h = 0.3020, pi = 0.0140). Although two of the host lobsters co-inhabit the coastal waters of Europe, a strong genetic structure (78.45% of the observed genetic variation) was detected among populations on all host species, indicating the existence of a reproductively isolated species on each lobster. In addition, genetic structure over long distances exists among populations on each host species. Such patterns can be explained by the limited dispersal ability of the cycliophoran chordoid larva. Demographic and phylogenetic analyses suggest old and possibly cryptic populations present on H. americanus and H. gammarus, while the latter may have experienced recent bottlenecks, perhaps during Pleistocene glaciations. Populations on N. norvegicus appear to be of recent origin.

Maxmen, A., W. E. Browne, M.Q. Martindale, and G. Giribet. 2005. “Neuroanatomy of sea spiders implies an appendicular origin of the protocerebral segment.” Nature 437: 1144-8.Abstract

Independent specialization of arthropod body segments has led to more than a century of debate on the homology of morphologically diverse segments, each defined by a lateral appendage and a ganglion of the central nervous system. The plesiomorphic composition of the arthropod head remains enigmatic because variation in segments and corresponding appendages is extreme. Within extant arthropod classes (Chelicerata, Myriapoda, Crustacea and Hexapoda--including the insects), correspondences between the appendage-bearing second (deutocerebral) and third (tritocerebral) cephalic neuromeres have been recently resolved on the basis of immunohistochemistry and Hox gene expression patterns. However, no appendage targets the first ganglion, the protocerebrum, and the corresponding segmental identity of this anterior region remains unclear. Reconstructions of stem-group arthropods indicate that the anteriormost region originally might have borne an ocular apparatus and a frontal appendage innervated by the protocerebrum. However, no study of the central nervous system in extant arthropods has been able to corroborate this idea directly, although recent analyses of cephalic gene expression patterns in insects suggest a segmental status for the protocerebral region. Here we investigate the developmental neuroanatomy of a putative basal arthropod, the pycnogonid sea spider, with immunohistochemical techniques. We show that the first pair of appendages, the chelifores, are innervated at an anterior position on the protocerebrum. This is the first true appendage shown to be innervated by the protocerebrum, and thus pycnogonid chelifores are not positionally homologous to appendages of extant arthropods but might, in fact, be homologous to the 'great appendages' of certain Cambrian stem-group arthropods.

Edgecombe, GD, and G Giribet. 2004. “Adding mitochondrial sequence data (16S rRNA and cytochrome c oxidase subunit I) to the phylogeny of centipedes (Myriapoda, Chilopoda): an analysis of morphology and four molecular loci. .” Journal of Zoological Systematics and Evolutionary Research 42: 89.134.
Giribet, G, G.D. Edgecombe, JM Carpenter, CA D'Haese, and WC Wheeler. 2004. “Is Ellipura monophyletic? A combined analysis of basal hexapod relationships with emphasis on the origin of insects..” Orignism Diversity Evolution 4: 319-340.
Giribet, G, MV Sorensen, P Funch, RM Kristensen, and W Sterrer. 2004. “Investigations into the phylogenetic position of Micrognathozoa using four molecular loci..” Cladistics 20: 1-13.
Huff, SW, D Campbell, DL Gustafson, C Lydeard, CR Altaba, and G Giribet. 2004. “Investigations into the phylogenetic relationships of the threatened freshwater pearl-mussels (Bivalvia, Unionoidea, Margaritiferidae) based on molecular data: implications for their taxonomy and biogeography..” Journal of Molluscan Studies 70: 379-388.
Edgecombe, GD, and G Giribet. 2004. “Molecular phylogeny of Australasian anopsobiine centipedes (Chilopoda: Lithobiomorpha)..” Invertrabrate Systematics 18: 235-249.
de Bivort, BL, and G Giribet. 2004. “A new genus of cyphophthalmid from the Iberian Peninsula with a phylogenetic analysis of the Sironidae (Arachnida: Opiliones: Cyphophthalmi) and a SEM database of external morphology..” Invertrabrate Systematics 18: 7-52.
Duran, S, G Giribet, and X Turon. 2004. “Phylogeographic history of the sponge Crambe crambe (Porifera, Poecilosclerida): range expansion and recent invasion of Macaronesian Islands from the Mediterranean Sea..” Molecular Ecology 13: 109-122.
Schwendinger, PJ, G Giribet, and H Steiner. 2004. “A remarkable new cave-dwelling Stylocellus (Opiliones, Cyphophthalmi) from Peninsular Malaysia, with a discussion on taxonomic characters in the family Stylocellidae..” Journal of Natural History 38: 1421-1435.
Schwendinger, PJ, and G Giribet. 2004. “The systematics of the south-east Asian genus Fangensis Rambla (Opiliones: Cyphophthalmi: Stylocellidae)..” Invertrabrate Systematics 19: 297-323.
Duran, S., C. Palacin, M. A. Becerro, X. Turon, and G. Giribet. 2004. “Genetic diversity and population structure of the commercially harvested sea urchin Paracentrotus lividus (Echinodermata, Echinoidea).” Mol Ecol 13: 3317-28.Abstract

The population structure of the edible Atlanto-Mediterranean sea urchin Paracentrotus lividus is described by analysing sequence variation in a fragment of the mitochondrial gene cytochrome c oxidase subunit I in 127 individuals from 12 localities across south-west Europe. The study revealed high levels of genetic diversity but low levels of genetic structure, suggesting a large degree of gene flow between populations and panmixis within each, the Mediterranean and Atlantic basins. However, we found significant genetic differentiation between the two basins probably due to restricted gene flow across the geographical boundary imposed by the area of the Strait of Gibraltar. Populations of P. lividus appeared to have experienced a recent demographic expansion in the late Pleistocene. We provide new evidence on the population structure of this commercial species, predicting a healthy stock of this sea urchin on the Mediterranean and Atlantic coasts.

Penas, A, and G Giribet. 2003. “Adiciones a la fauna malacologica del litoral del Garraf (NE de la Peninsula Iberica)..” Iberus 21: 177-189.