Lotta M. Hardman

Systematic relationships of hymenolepidid cestodes of rodents and shrews inferred from sequences of 28S ribosomal RNA

Haukisalmi, V., Hardman, L. M., Foronda, P., Feliu, C., Laakkonen, J., Niemimaa, J., Lehtonen, J. T. & Henttonen, H. (2010). Systematic relationships of hymenolepidid cestodes of rodents and shrews inferred from sequences of 28S ribosomal RNA. —Zoologica Scripta, 39, 631–641.

The relative importance of body size and paleoclimatic change as explanatory variables influencing lineage diversification rate: an evolutionary analysis of bullhead catfishes (Siluriformes: Ictaluridae).

We applied Bayesian phylogenetics, divergence time estimation, diversification pattern analysis, and parsimony-based methods of ancestral state reconstruction to a combination of nucleotide sequences, maximum body sizes, fossils, and paleoclimate data to explore the influence of an extrinsic (climate change) and an intrinsic (maximum body size) factor on diversification rates in a North American clade of catfishes (Ictaluridae). We found diversification rate to have been significantly variable over time, with significant (or nearly significant) rate increases in the early history of Noturus. Though the latter coincided closely with a period of dramatic climate change at the Eocene-Oligocene boundary, we did not detect evidence for a general association between climate change and diversification rate during the entire history of Ictaluridae. Within Ictaluridae, small body size was found to be a near significant predictor of species richness. Morphological stasis of several species appears to be a consequence of a homoplastic increase in body size. We estimated the maximum standard length of the ictalurid ancestor to be approximately 50 cm, comparable to Eocene ictalurids (Astephus) and similar to modern sizes of Ameiurus and their Asian sister-taxon Cranoglanis. During the late Paleocene and early Eocene, the ictalurid ancestor diversified into the lineages represented by the modern epigean genera. The majority of modern species originated in the Oligocene and Miocene, most likely according to a peripheral isolates model of speciation. We discuss the difficulties of detecting macroevolutionary patterns within a lineage history and encourage the scrutiny of the terminal Eocene climatic event as a direct promoter of diversification.

Molecular systematics and morphometrics of Anoplocephaloides dentata (Cestoda, Anoplocephalidae) and related species in voles and lemmings

This study presents extensive molecular phylogenetic and morphometric data for Anoplocephaloides dentata (Galli‐Valerio, 1905)‐like cestodes (Anoplocephalidae) and related species parasitizing arvicoline rodents (voles and lemmings) in the Holarctic region. The molecular phylogeny is based on nucleotide sequences of cytochrome oxidase I (mtDNA) and 28S ribosomal RNA. Anoplocephaloides dentata‐like cestodes included three main clades, two in western Eurasia and one in the Holarctic region (excluding western Eurasia). Three well‐supported sublineages were included in the southern European clade, one of which represents the true A. dentata from Chionomys nivalis and sympatric Microtus arvalis and Dinaromys bogdanovi. These clades generally had non‐overlapping distributions and showed a preference for certain host species. Multivariate analysis of morphometric data failed to discriminate unambiguously the various A. dentata‐like lineages recovered in the molecular phylogeny, although two to three of the (sub)lineages were morphologically divergent. The overall evidence suggests, however, that instead of a single host‐generalist species there are at least five more or less host‐specific species of A. dentata‐like cestodes. Colonization of new host lineages seems to have been the predominant mode of diversification, suggested by the considerable incongruence between host and parasite phylogenies at multiple taxonomic levels. Based on the results of the molecular survey, a redescription and neotype designation are provided for A. dentata.

Molecular systematics of the Holarctic Anoplocephaloides variabilis (Douthitt, 1915) complex, with the proposal of Microcephaloides n. g. (Cestoda: Anoplocephalidae).

Phylograms based on mitochondrial cytochrome oxidase I gene sequences show that the Anoplocephaloides variabilis (Douthitt, 1915)-like cestodes (Cestoda: Anoplocephalidae) from voles (Microtus spp.) and Paranoplocephala krebsi Haukisalmi, Wickström, Hantula & Henttonen, 2001 from collared lemmings (Dicrostonyx spp.) comprise a monophyletic group within the anoplocephaline cestodes. The patterns of phylogenetic, biological and/or biogeographical distinction suggest six or seven species of A. variabilis-like cestodes, including P. krebsi. However, at this time we decline to describe them as a series of new species as no straightforward morphological differences were found between the A. variabilis-like cestodes. A new genus, Microcephaloides n. g., is proposed for the cestodes earlier assigned to A.variabilis, A. cf. variabilis, A. tenoramuraiae Genov & Georgiev, 1988 and P. krebsi. A redescription is provided for the type-species, M. variabilis n. comb., from pocket gophers (Geomys spp. and Thomomys spp.). In addition to Anoplocephaloides Baer, 1927 (sensu stricto) and Microcephaloides, Paranoplocephaloides Gulyaev, 1996, Flabelloskrjabinia Spasskii, 1951 and Leporidotaenia Genov, Murai, Georgiev & Harris, 1990 are considered valid genera among cestodes previously assigned to Anoplocephaloides (sensu Rausch, 1976). The host spectrum and present phylogenetic data suggest that Microcephaloides has been primarily associated with voles (Microtus spp.) and its basal lineage now occurs in M. guentheri (Danford & Alston) in Turkey. Although the distribution and current host of the basal lineage suggest a western Palaearctic origin, subsequent diversification has probably occurred in eastern Beringia, because most of the more derived lineages occur partly or exclusively in Alaska.

Morphological and molecular characterisation of Paranoplocephala buryatiensis n. sp. and P. longivaginata Chechulin & Gulyaev, 1998 (Cestoda: Anoplocephalidae) in voles of the genus Clethrionomys

A new species, Paranoplocephala buryatiensis n. sp. (Cestoda:Anoplocephalidae), is described from the grey-sided vole Clethrionomys rufocanus (Sundevall) in the Republic of Buryatia (Russian Federation) and compared with P. longivaginata Chechulin & Gulyaev, 1998, a parasite of the red vole C. rutilus (Pallas) in the same region. P. buryatiensis n. sp. and P. longivaginata both have an exceptionally long vagina and cirrus, unique features among known species of Paranoplocephala Lühe, 1910. The new species differs from P. longivaginata primarily by its wider and more robust body, lower length/width ratio of mature proglottides, tendency of testes to occur in two separate groups, seminal receptacle of a different shape and the position of the cirrus-sac with respect to the ventral longitudinal osmoregulatory canal. The cytochrome oxidase subunit I (COI) sequence data support the independent status of these species, and show that they form a monophyletic assemblage within Paranoplocephala (sensu lato). Assuming cospeciation, an indirect calibration using host speciation dates estimated a rate of mtDNA substitution of 1.0–1.7% pairwise (0.5–0.85% per lineage) sequence divergence per million years. A faunistic review of Paranoplocephala species in C. rufocanus and C. rutilus in the Holarctic region is presented.

Comparison of the phylogenetic performance of neodermatan mitochondrial protein-coding genes

We examined the ability of all protein‐coding genes of 11 neodermatan mitochondrial genomes to recover the phylogeny of their combination. We subsampled randomly selected lengths (1–6000 bp) of contiguous sequence to consider the effect of length (100–6000 bp) on performance. All genes performed as well as randomly selected regions except ND2 (better) and ND5 (worse). All expected nodes were recovered (> 90% bootstrap) when 4.0 Kb had been sampled; 40 samples of 100 performed as well as four samples of 1000.

Phylogenetic relationships of the anoplocephaline cestodes of Australasian marsupials and resurrection of the genus Wallabicestus Schmidt, 1975

A phylogenetic analysis was carried out on rDNA of 45 species of anoplocephaline cestodes from marsupial hosts. The exclusively Australasian genera Progamotaenia Nybelin, 1917, Triplotaenia Boas, 1902, Paramoniezia Maplestone & Southwell, 1923 and Phascolotaenia Beveridge, 1976 formed a monophyletic clade, and the previously suggested relationship between the Australasian species of the cosmopolitan genus Bertiella Stiles & Hassall, 1902 and species of Progamotaenia was supported. A low degree of phyletic co-evolution was detected within endemic Australasian clades. Colonisation rather than co-speciation appeared to be the principal means of diversification within the Australasian anoplocephaline radiation. The clade of bile duct-inhabiting Progamotaenia species emphasises the role of microhabitat rather than host species as a driver of speciation. Triplotaenia undosa Beveridge, 1976 described from a wide variety of macropodid hosts was found to be polyphyletic and a proposition was made to resurrect Wallabicestus Schmidt, 1975, with W. ewersi Schmidt, 1975 as the type-species and including W. ualabati (Beveridge, 2009) n. comb. [previously Progamotaeniaualabati Beveridge, 2009].

Systematic relationships of Mosgovoyia Spasskii, 1951 (Cestoda: Anoplocephalidae) and related genera inferred from mitochondrial and nuclear sequence data

The present study evaluates the phylogenetic position and systematic relationships of two species of Mosgovoyia Spasskii, 1951 and related genera (Cestoda: Anoplocephalidae) based on sequences of 28S ribosomal RNA and mitochondrial NADH dehydrogenase subunit 1 (Nad1) genes. Both molecular data-sets show that M. pectinata (Goeze, 1782) and Schizorchis caballeroi Rausch, 1960 are sister species and that they are phylogenetically independent from M. ctenoides (Railliet, 1890). This shows unambiguously that Mosgovoyia [sensu Beveridge (1978)] is a non-monophyletic assemblage, supporting the validity of Neoctenotaenia Tenora, 1976, erected for M. ctenoides. The results also show that the morphologically related Ctenotaenia marmotae (Fröhlich, 1802) is the sister species of Andrya rhopalocephala (Riehm, 1881) and therefore represents a more derived lineage. Modified diagnoses are provided for Mosgovoyia and Neoctenotaenia.

Molecular systematics and Holarctic phylogeography of cestodes of the genus Anoplocephaloides Baer, 1923 s. s. (Cyclophyllidea, Anoplocephalidae) in lemmings (Lemmus, Synaptomys)

The present molecular systematic and phylogeographic analysis is based on sequences of cytochrome c oxidase subunit 1 (cox1) (mtDNA) and 28S ribosomal DNA and includes 59 isolates of cestodes of the genus Anoplocephaloides Baer, 1923 s. s. (Cyclophyllidea, Anoplocephalidae) from arvicoline rodents (lemmings and voles) in the Holarctic region. The emphasis is on Anoplocephaloides lemmi (Rausch 1952) parasitizing Lemmus trimucronatus and Lemmus sibiricus in the northern parts of North America and Arctic coast of Siberia, and Anoplocephaloides kontrimavichusi (Rausch 1976) parasitizing Synaptomys borealis in Alaska and British Columbia. The cox1 data, 28S data and their concatenated data all suggest that A. lemmi and A. kontrimavichusi are both non‐monophyletic, each consisting of two separate, well‐defined clades, that is independent species. As an example, the sister group of the clade 1 of A. lemmi, evidently representing the ‘type clade’ of this species, is the clade 1 of A. kontrimavichusi. For A. kontrimavichusi, it is not known which one is the type clade. There is also fairly strong evidence for the non‐monophyly of Anoplocephaloides dentata (Galli‐Valerio, 1905)‐like species, although an earlier phylogeny suggested that this multispecies assemblage may be monophyletic. The results suggest a deep phylogenetic codivergence of Lemmus spp. and A. lemmi, primarily separating the two largely allopatric host and parasite species at the Kolyma River in east Siberia. There are also two allopatric sublineages within each main clade/species of A. lemmi and Lemmus, but the present distributions of the sublineages within the eastern L. trimucronatus and clade 1 of A. lemmi are not concordant. This discrepancy may be most parsimoniously explained by an extensive westward distributional shift of the easternmost parasite subclade. The results further suggest that the clade 1 of A. kontrimavichusi has diverged through a host shift from the precursor of L. trimucronatus to S. borealis.

Taxonomy and genetic divergence of Paranoplocephala kalelai (Tenora, Haukisalmi et Henttonen, 1985) (Cestoda, Anoplocephalidae) in the grey-sided vole Myodes rufocanus in northern Fennoscandia

Paranoplocephala kalelai (Tenora, Haukisalmi et Henttonen, 1985) is an anoplocephalid cestode that primarily parasitizes the grey-sided vole Myodes rufocanus (syn. Clethrionomys rufocanus) in northern Fennoscandia. In a preliminary molecular phylogenetic analysis, the cytochrome oxidase I (mtDNA) sequences of P. kalelai formed two divergent sublineages originating from two different localities in northern Finland and northern Norway. The present data confirm the existence of two strongly supported clades and show that their geographic distributions are overlapping in northernmost Finland. Relatively deep genetic divergence and coexistence of the two main clades at one of the localities suggest that the material may include two biological species. However, because the specimens representing the two mtDNA clades of P. kalelai are not morphometrically sufficiently differentiated and because the mtDNA clade of the specimens from the type locality is unknown, they are not assigned to different species. Comparison with the existing phylogeographic data of M. rufocanus suggests that the genetic structure of this host-specific cestode reflects the glacial and post-glacial history of its primary host. A redescription is presented for P. kalelai.