Separate Species Status Research Articles

Mitochondrial DNA corroborates the species distinctiveness of the Planalto (Thamnophilus pelzelni Hellmayr, 1924) and the Sooretama (T. ambiguus Swainson, 1825) Slaty-antshrikes (Passeriformes: Thamnophilidae)

The Thamnophilus punctatus complex has been recently reviewed on the basis of morphological and vocal characters, and is divided in six different species. Two of the new species, although well defined on the basis of morphological differences, could not be unambiguously distinguished through their loud songs. The Planalto Slaty-antshrike (Thamnophilus pelzelni) and the Sooretama Slaty-antshrike (T. ambiguus) are most easily distinguished by subtle and localized changes in plumage colors of males and females. In the present study we used sequences of the control region, Cytochrome b, and ND2 genes, of the mitochondrial DNA (mtDNA) to evaluate the levels of molecular differentiation between these two species. The mean pairwise distance between the two species was 3.8%, while it varied from 2.7% to 4.9% for each mtDNA region. Although extensive variation was also detected among haplotypes within species, especially for T. ambiguus, we suggest that the genetic divergence found between T. ambiguus and T. pelzelni is high enough to corroborate the separate species status of these two antbird taxa.

Species limits of Solanum berthaultii Hawkes and S. tarijense Hawkes and the implications for species boundaries in Solanum sect. Petota

Solanum berthaultii and S. tarijense are two wild potato (sect. Petota) species distributed from Bolivia to northern Argentina. All authors have accepted them as good species since their publication in 1944, but they have been hypothesized to hybridize extensively with each other and with other species, despite their classification into different series and superseries by some authors. This study is a molecular counterpart (AFLPs, plastid DNA restriction site data, survey of a plastid DNA deletion) to a prior morphological study of these two species. AFLP data show weak support for separate species status for some accessions, but with many exceptions. In agreement with the morphological results we place S. tarijense into synonymy of S. berthaultii, and use herbarium specimen data for a taxonomic treatment to include a description, synonymy, and mapping of all accessions. We show similar taxonomic problems in sect. Petota and suggest that there will be a continuing trend of reduction of names in wild potatoes.

Catenulispora rubra sp. nov., an acidophilic actinomycete isolated from forest soil

In the course of screening novel secondary metabolites, an acidophilic actinomycete strain, designated Aac-30(T), was isolated from forest soil and subjected to a polyphasic taxonomic characterization study. It grew well on media in which the pH ranged from 4 to 6, but not on medium with pH adjusted to 7. It possessed ll-diaminopimelic acid and glycine in the cell-wall peptidoglycan, MK-9(H6) and MK-9(H8) as major isoprenoid quinones, iso-C(16 : 0) and anteiso-C(17 : 0) as major cellular fatty acids, and phosphatidylglycerol and phosphatidylinositol as polar lipids. The G+C content of the genomic DNA was 69.1 mol%. Phylogenetic analyses based on 16S rRNA gene sequences showed that the organism belonged to the family Catenulisporaceae and consistently formed a monophyletic cluster with members of the genus Catenulispora. Physiological, biochemical and chemotaxonomic data revealed that this novel organism could be readily differentiated from recognized members of the genus Catenulispora and that it merits separate species status. Based on the phenotypic and genetic evidence presented, strain Aac-30(T) is considered to represent a novel species of the genus Catenulispora, for which the name Catenulispora rubra sp. nov. is proposed. The type strain is Aac-30(T) (=NBRC 101179(T)=DSM 44948(T)).

Avibacterium endocarditidis sp. nov., isolated from valvular endocarditis in chickens

A novel species of the Pasteurellaceae, Avibacterium endocarditidis sp. nov., is proposed based upon characterization of 27 isolates from valvular endocarditis in adult broiler parents. All isolates shared the same PFGE type after digestion of DNA with SmaI and XbaI. In addition, all isolates meet the phenotypic characters for the genus Avibacterium. Separation of the novel species from other species of Avibacterium was possible by means of tests for catalase, symbiotic growth, aerobic growth on agar, acid production from glycerol, xylitol, (+)-L-arabinose, (-)-D-mannitol, (-)-D-sorbitol, (-)-L-fucose, (+)-D-galactose, maltose, trehalose, raffinose and dextrin in addition to reactions with ONPG (beta-galactosidase) and PNPG (alpha-glucosidase). The closest relationship was observed with Avibacterium gallinarum which, however, can be separated from Avibacterium endocarditidis in acid production from (-)-D-mannitol, (-)-D-sorbitol and (-)-L-fucose. The highest 16S rRNA gene sequence similarity (98.4 %) was found to strain Modesto, belonging to serogroup C of Avibacterium paragallinarum. recN gene DNA sequence similarities corrected by the formula of Zeigler (2003) (Int J Syst Evol Microbiol 53, 1893-1900) documented 85 % or less DNA sequence similarity between the type strain of Avibacterium endocarditidis and species of Avibacterium, confirming the separate species status of this taxon according to the multilocus sequence analysis method of Kuhnert & Korczak (2006) (Microbiology 152, 2537-2548). The type strain of Avibacterium endocarditidis sp. nov., strain 20186H4H1(T) (=CCUG 52860(T) =DSM 18224(T)), was isolated from valvular endocarditis of a chicken in Denmark in 2004.

Chryseobacterium luteum sp. nov., associated with the phyllosphere of grasses

Three isolates obtained from grass samples were investigated by means of a polyphasic taxonomic study and were shown to represent a novel species within the genus Chryseobacterium. Comparison of 16S rRNA gene sequences and phenotypic features indicated that the three isolates belonged to a single species. On the basis of 16S rRNA gene sequence analysis, the closest phylogenetic neighbours were Chryseobacterium shigense and Chryseobacterium vrystaatense, which formed a stable cluster with the isolates; this phylogeny was supported by a high bootstrap value and was obtained using different treeing methods. A DNA-DNA hybridization study with the closest neighbour, C. shigense DSM 17126(T) (98.3 % 16S rRNA gene sequence similarity), clearly demonstrated a separate species status for the grass isolate strain P 456/04(T). Comparisons involving physiological properties and whole-cell fatty acid profiles confirmed this result at the phenotypic level. On the basis of these results, strain P 456/04(T) represents a novel species of the genus Chryseobacterium, for which the name Chryseobacterium luteum sp. nov. is proposed. The type strain is P 456/04(T) (=DSM 18605(T) =LMG 23785(T)).

Pseudomonas lurida sp. nov., a fluorescent species associated with the phyllosphere of grasses

The taxonomic position of a group of fluorescent pseudomonad strains isolated from the phyllosphere of grasses was investigated through a polyphasic approach. Riboprinting analysis revealed highly similar patterns for the investigated strains which supported, together with the agreement of many phenotypic characteristics, their affiliation to the same species. A comparison of 16S rRNA gene sequences of strain P 513/18(T), a representative strain from the grass isolates, revealed that it was affiliated to the cluster of the 'Pseudomonas fluorescens group', with Pseudomonas costantinii as the closest phylogenetic neighbour. However, DNA-DNA hybridization showed a clear demarcation at the species level between strain P 513/18(T) and P. costantinii. Furthermore, a comparison of riboprint patterns with Pseudomonas species clustering next to the novel grass isolates on the basis of 16S rRNA gene sequences supported their separate species status at the phylogenetic level. Based on phenotypic features, the novel isolates could also be differentiated from the other fluorescent Pseudomonas species that share positive arginine dihydrolase and oxidase reactions. As a consequence of these phenotypic and phylogenetic analyses, the isolates from the grass pyllosphere represent a novel species for which the name Pseudomonas lurida sp. nov. is proposed. The type strain is P 513/18(T) (=DSM 15835(T)=LMG 21995(T)).

Bursaphelenchus debrae n. sp. (Nematoda: Parasitaphelenchidae), an associate of the bee Halictus brunnescens in Turkey

Abstract Bursaphelenchus debrae n. sp. was cultured from dauer juveniles recovered from the poison sac of a female sweat bee, Halictus brunnescens from Ankara, Turkey, in June 2004. The new species appears to be most similar to B. kevini and B. anatolius based upon the synapomorphies of their associations with soil-dwelling halictid bees, morphological features such as four lateral incisures, male caudal papillae arrangement, spicule morphology, female tail shape and ratio a, and molecular analysis of sequences of the D2/D3 expansion segments of the large subunit (LSU) rDNA and partial mitochondrial DNA COI (mtCOI). In addition to significant molecular sequence differences in LSU and COI consistent with separate species status, B. debrae n. sp. can be differentiated from both B. kevini and B. anatolius by differences in the host halictid bee species with which they are phoretically associated, rostrum shape and size, and presence of a unique protuberance on the ventral aspect of the spicules. The nematode is mycophagous and can be cultured in the laboratory at 23°C on Monilinia fructicola growing on lactic acid-treated, 5% glycerin-supplemented potato dextrose agar (LGPDA).

Molecules, morphometrics and new fossils provide an integrated view of the evolutionary history of Rhinopomatidae (Mammalia: Chiroptera)

BackgroundThe Rhinopomatidae, traditionally considered to be one of the most ancient chiropteran clades, remains one of the least known groups of Rhinolophoidea. No relevant fossil record is available for this family. Whereas there have been extensive radiations in related families Rhinolophidae and Hipposideridae, there are only a few species in the Rhinopomatidae and their phylogenetic relationship and status are not fully understood.ResultsHere we present (a) a phylogenetic analysis based on a partial cytochrome b sequence, (b) new fossils from the Upper Miocene site Elaiochoria 2 (Chalkidiki, Greece), which represents the first appearance datum of the family based on the fossil record, and (c) discussion of the phylogeographic patterns in both molecular and morphological traits. We found deep divergences in the Rhinopoma hardwickii lineage, suggesting that the allopatric populations in (i) Iran and (ii) North Africa and the Middle East should have separate species status. The latter species (R. cystops) exhibits a shallow pattern of isolation by distance (separating the Middle East and the African populations) that contrasts with the pattern of geographic variation in the morphometrical traits. A deep genetic gap was also found in Rhinopoma muscatellum (Iran vs. Yemen). We found only minute genetic distance between R. microphyllum from the Levant and India, which fails to support the sub/species distinctness of the Indian form (R. microphyllum kinneari).ConclusionThe mtDNA survey provided phylogenetic tree of the family Rhinopomatidae for the first time and revealed an unexpected diversification of the group both within R. hardwickii and R. muscatellum morphospecies. The paleobiogeographic scenario compiled in respect to molecular clock data suggests that the family originated in the region south of the Eocene Western Tethyan seaway or in India, and extended its range during the Early Miocene. The fossil record suggests a Miocene spread into the Mediterranean region, followed by a post-Miocene retreat. Morphological analysis compared with genetic data indicates considerable phenotypic plasticity in this group.

Microsatellite Analysis of Japanese Sea Cucumber, Stichopus (Apostichopus) japonicus, Supports Reproductive Isolation in Color Variants

The genetic relationship among the three color variants (Red, Green, and Black) of the Japanese sea cucumber, S. japonicus, was investigated using 11 microsatellite markers. Genetic differentiation testing among the three sympatric color types showed the strong heterogeneity of Red (p<0.001), while no significant difference was observed between Green and Black (p=0.301 to 0.961). UPGMA trees constructed from 10 sample lots from 5 localities showed two distinct clusters, one from the Red types and the other from the Green and Black types. In addition, the sympatric Green and Black formed one subcluster with strong bootstrap support at each locality. These results indicate the separate species status of Red and the other color types, and also support the population identity of sympatric Green and Black.

Blastococcus jejuensis sp. nov., an actinomycete from beach sediment, and emended description of the genus Blastococcus Ahrens and Moll 1970

A novel actinomycete, strain KST3-10(T), was isolated from sand sediment of a beach in Jeju, Korea, and was subjected to polyphasic taxonomic characterization. The organism produced circular, smooth, translucent, apricot-coloured colonies comprising coccoid- or rod-shaped cells. Phylogenetic analyses based on 16S rRNA gene sequences showed that the organism belonged to the family Geodermatophilaceae and consistently formed a distinct sub-branch outside the radiation of the genus Blastococcus. The organism showed 16S rRNA gene sequence similarity values of 98.2 % with respect to Blastococcus aggregatus DSM 4725(T) and 98.1 % with respect to Blastococcus saxobsidens BC444(T). The type strains of the two Blastococcus species shared 98.2 % sequence similarity with respect to each other, whereas the levels of sequence similarity between the novel organism and the type strains of the less closely related neighbours, Modestobacter multiseptatus and Geodermatophilus obscurus, were in the range 96.2-96.9 %. The physiological, biochemical and chemotaxonomic data revealed that the novel organism can be readily differentiated from members of the genus Blastococcus and that it merits separate species status. On the basis of the phenotypic and genotypic evidence, strain KST3-10(T) represents a novel species of the genus Blastococcus, for which the name Blastococcus jejuensis sp. nov. is proposed. The type strain is KST3-10(T) (=NRRL B-24440(T)=KCCM 42251(T)).

Morphology and systematics of Bursaphelenchus gerberae n. sp. (Nematoda: Parasitaphelenchidae), a rare associate of the palm weevil, Rhynchophorus palmarum in Trinidad

Bursaphelenchus gerberae n. sp., a rare associate of the American palm weevil, Rhynchophorus palmarum in Trinidad, is described and illustrated. Adults of B. gerberae n. sp. were examined with scanning electron microscopy (SEM) for ultrastructural comparisons with other members of the genus. Bursaphelenchus paracorneolus, B. hofmanni and B. hylobianum appear to be the closest related taxa to B. gerberae n. sp. based upon shared morphological features of male caudal papillae arrangement, general spicule morphology, female tail shape, and molecular analysis of the near-full length small subunit (SSU) rDNA, D2D3 expansion segments of the large subunit (LSU) rDNA and partial mitochondrial DNA COI. In addition to significant molecular sequence differences in SSU, LSU and mtCOI consistent with separate species status, B. gerberae n. sp. can be differentiated from B. paracorneolus by differences in bursa and condylus shape of males, and c’ in females, from B. hofmanni by differences in rostrum and condylus shape and spicule curvature in males, and c’ in females, and from B. hylobianum by differences in the number of lateral incisures, and rostrum shape, tapering and curvature of the spicule lamina, and cucullus shape in males. Bursaphelenchus gerberae n. sp. is also close to B. corneolus. Unfortunately, this isolate was not available for sequencing attempts, but differs from B. gerberae n. sp. in lack of stylet knobs in both sexes and relative postuterine sac length in females. Population growth of B. gerberae n. sp. was measured in a time-course experiment at 23° C in the laboratory on cultures of the fungus, Monilinia fructicola grown on lactic acid treated, 5% glycerol-supplemented potato dextrose agar (LGPDA). Nematode counts rapidly increased from 500 to about 600,000 per plate within 14 days and then dropped to and plateaued at about 300,000 for up to 28 days.

Identity of the causal agents of human babesiosis in Europe

Most cases of human babesiosis are caused either by Babesia divergens in Europe or Babesia microti in America. B. microti, once regarded as a single species, occurs as a world-wide species complex and although both phenotypic and genotypic features lend support to suggestions that zoonotic B. microti may occur in Europe, convincing medical evidence is lacking. Several B. divergens-like parasites have emerged in the last few years, but 18S rRNA gene analysis suggests that B. divergens ‘sensu stricto’ is restricted to European (and North African) cattle. Some of the B. divergens-like parasites only differ from the bovine type by a few bases, and it remains to be determined whether this is sufficient to accord them separate species status. Comparative biology should support genetic data in taxonomic studies of both B. divergens and B. microti.

Revision of the genus Latrunculia du Bocage, 1869 (Porifera: Demospongiae: Latrunculiidae) with descriptions of new species from New Caledonia and the Northeastern Pacific

Revision of the genus Latrunculia du Bocage, 1869, has resulted in 27 of 36 species considered to be valid. Many species have been reassigned to genera in the poecilosclerid family Podospongiidae, in particular, and many have been transferred to other Latrunculiidae genera. Latrunculia apicalis var. biformis (Kirkpatrick 1908) and Latrunculia apicalis var. basilis (Kirkpatrick 1908) have been elevated to full and separate species status, as L. biformis Kirkpatrick and L. basilis Kirkpatrick. Two new species have been described, from New Caledonia (L. novaecaledoniae sp. nov.) and the northeastern Pacific (L. austini sp. nov.). This revision also formally recognizes the two morphological subgroups triverticillata and spinispiraefera hypothesized by Alvarez et al. (2002), as the new subgenera Latrunculia (Latrunculia) subgen. nov. and Latrunculia (Biannulata) subgen. nov.. The primary distinction between these two groups is the morphology of the anisodiscorhabd microscleres. The anisodiscorhabds of Latrunculia (Latrunculia) species have a basal whorl just above the manubrium in addition to two centralized whorls of projections. The anisodiscorhabds of Latrunculia (Biannulata) species lack this basal whorl. There is some indication that there are geographic and habitat differences between the two groups.

Shape variation in surface and cave populations of the armoured catfishes Ancistrus(Siluriformes: Loricariidae) from the São Domingos karst area, upper Tocantins River, Brazil

Body shape of four distinct populations of Ancistrus cryptophthalmus from different caves in the São Domingos karst area and the local epigean (surface)Ancistrus species were compared using geometric morphometrics. Angélica and Bezerra catfishes were closer to each other and successively to the studied sample of epigean catfishes than to Passa Três and São Vicente I catfishes. Greater similarity between catfishes from the Angélica‐Bezerra cave system to epigean catfishes than to other cave catfishes may represent a plesiomorphic feature. On the other hand, the present analyses allowed the distinction between Passa Três and São Vicente I catfishes, which inhabited the same cave system. Topographic isolation due to the presence of several waterfalls interposed between the stream reaches where these catfishes live may explain such morphological differentiation. Also, the presence of a waterfall downstream of the reach where the Angélica sample was obtained may have contributed to the partial isolation of these catfishes from those living in Bezerra Cave. Differences in population sizes probably influenced the degrees of morphological differentiation observed among the cave populations. The mosaic distribution of character states indicated that the four populations of A. cryptophthalmus have evolved rather independently, but the continuous variation suggests a recent connection between these populations, perhaps with a limited gene flow. Considering other features such as reduction of eyes and pigmentation, and changes in body shape, a separate species status for the epigean and hypogean Ancistrus species from the São Domingos karst area has been maintained.

Morphological Differentiation Between Geographically Separated Populations of Neomysis integer and Mesopodopsis slabberi (Crustacea, Mysida)

Morphological variation was examined in Neomysis integer and Mesopodopsis slabberi, two abundant, low dispersal mysid species (Crustacea, Mysida) along the European coasts. Both species dominate the hyperbenthic communities in the northeast Atlantic, and M. slabberi is also widely distributed in the Mediterranean and Black Sea. Three populations of these species were sampled throughout their distribution range; samples of N. integer were collected in the northeast Atlantic Eems-Dollard, Gironde and Guadalquivir estuaries; in the case of M. slabberi, mysids were sampled in two northeast Atlantic estuaries (Eems-Dollard and Guadalquivir) and one Mediterranean site (Ebro Delta). A total of 12 morphometric and 2 meristic characters were measured from 30–64 mysids per sample. Multivariate analysis showed clear morphometric differences between populations of both species. The morphological differentiation within M. slabberi was highly concordant with the available genetic data from mitochondrial loci, pointing to a large divergence between the Atlantic and Mediterranean populations. However, due to some overlap of individuals between the different populations, the present morphometric analysis does not suffice to assign the different populations to a separate (sub)species status. In the case of N. integer, the morphometric patterns showed a divergence of the Gironde population. Differentiation of populations within this mysid, as in M. slabberi, were mainly related to eye and telson morphology. Potential interactions of the mysid morphology and environmental conditions are discussed.

Fatty acid and DNA analyses of Permian bacteria isolated from ancient salt crystals reveal differences with their modern relatives

The isolation of living microorganisms from primary 250-million-year-old (MYA) salt crystals has been questioned by several researchers. The most intense discussion has arisen from questions about the texture and age of the crystals used, the ability of organisms to survive 250 million years when exposed to environmental factors such as radiation and the close similarity between 16S rRNA sequences in the Permian and modern microbes. The data in this manuscript are not meant to provide support for the antiquity of the isolated bacterial strains. Rather, the data presents several comparisons between the Permian microbes and other isolates to which they appear related. The analyses include whole cell fatty acid profiling, DNA-DNA hybridizations, ribotyping, and random amplified polymorphic DNA amplification (RAPD). These data show that the Permian strains, studied here, differ significantly from their more modern relatives. These differences are accumulating in both phenotypic and molecular areas of the cells. At the fatty acid level the differences are approaching but have not reached separate species status. At the molecular level the variation appears to be distributed across the genome and within the gene regions flanking the highly conserved 16S rRNA itself. The data show that these bacteria are not identical and help to rule out questions of contamination by putatively modern strains.

Essential oil constituents and RAPD markers to establish species relationship in Cymbopogon Spreng. (Poaceae)

Nineteen Cymbopogon taxa belonging to 11 species, two varieties, one hybrid taxon and four unidentified species were analysed for their essential oil constituents and RAPD profiles to determine the extent of genetic similarity and thereby the phylogenetic relationships among them. Remarkable variation was observed in the essential oil yield ranging from 0.3% in Cymbopogon travancorensis Bor. to 1.2% in Cymbopogon martinii (Roxb.) Wats var. motia. Citral, a major essential oil constituent, was employed as the base marker for chemotypic clustering. Based on genetic analysis, elevation of Cymbopogon flexuosus var. microstachys (Hook. F.) Soenarko to species status and separate species status for C. travancorensis Bor., which has been merged under C. flexuosus (Steud.) Wats were suggested towards resolving some of the taxonomic complexes in Cymbopogon. The separate species status for the earlier proposed varieties of C. martinii (motia and sofia) is further substantiated by these analyses. The unidentified species of Cymbopogon have been observed as intermediate forms in the development of new taxa.

Mitochondrial DNA sequence evidence supporting the recognition of a new North Atlantic Pseudostichopus species (Echinodermata: Holothuroidea)

A new species of the synallactid sea cucumber genus Pseudostichopus is described, P. aemulatus sp. nov., based on genetic (DNA sequences of the mitochondrial gene Cytochrome Oxidase I [COI] gene) and morphological characters. A comparative molecular study with two other species of the same genus (P. villosus and P. mollis) and from a different family (Isostichopus fuscus) was carried out in order to clarify its taxonomic identity. The nucleotide distance between P. aemulatus sp. nov. and P. villosus and P. mollis is sufficient to support distinct species status. The estimated difference in the number of amino acids, coded for by a partially sequenced COI gene, within the species of the family Synallactidae ranged from 4 to 18. The phylogenetic analysis clearly supports separate species status of these sympatric morphotypes, as indicated by the morphological analysis.

Molecular systematics of Acarus siro s. lat., a complex of stored food pests

The astigmatid mite Acarus siro (Linnaeus 1758) is an important agricultural pest and environmental allergen. However, it is likely that many mites described in the literature as A. siro, collected from both outdoor and stored product habitats, may belong to one of its sibling species, A. farris [Ent. Ber. Amst. 2 (26) (1905) 20] or A. immobilis [Bull. Br. Mus. Nat. Hist. 11 (1964a) 413; Acarologia. 6 (Suppl) (1964) 101]. The three species are difficult to separate morphologically, gene exchange between some of them is possible and, although each species displays environmental preferences, they occur together in some environments. This raises a question about their separate species status. In a pilot study, we investigated whether genetic data supported the separate species status of these forms. Both nuclear (the second internal transcribed spacer region [ITS-2] of the ribosomal cistron) and mitochondrial (cytochrome oxidase subunit I, mtcoxI hereafter) loci were employed for this purpose. Mtcox1 data does not conflict the differentiation into three separate species and while the ITS2 data were problematic for this group of mites it suggested that a congener, Acarus gracilis [Ann. Mag. Nat. Hist. 10 (1957) 753], is basal to the A. siro species complex.

Molecular systematics of Acarus siro s. lat., a complex of stored food pests*1

The astigmatid mite Acarus siro (Linnaeus 1758) is an important agricultural pest and environmental allergen. However, it is likely that many mites described in the literature as A. siro, collected from both outdoor and stored product habitats, may belong to one of its sibling species, A. farris [Ent. Ber. Amst. 2 (26) (1905) 20] or A. immobilis [Bull. Br. Mus. Nat. Hist. 11 (1964a) 413; Acarologia. 6 (Suppl) (1964) 101]. The three species are difficult to separate morphologically, gene exchange between some of them is possible and, although each species displays environmental preferences, they occur together in some environments. This raises a question about their separate species status. In a pilot study, we investigated whether genetic data supported the separate species status of these forms. Both nuclear (the second internal transcribed spacer region [ITS-2] of the ribosomal cistron) and mitochondrial (cytochrome oxidase subunit I, mtcoxI hereafter) loci were employed for this purpose. Mtcox1 data does not conflict the differentiation into three separate species and while the ITS2 data were problematic for this group of mites it suggested that a congener, Acarus gracilis [Ann. Mag. Nat. Hist. 10 (1957) 753], is basal to the A. siro species complex.