Carmen Guzmán-Cornejo

Amblyomma cajennense (Fabricius, 1787) (Acari: Ixodidae), the Cayenne tick: phylogeography and evidence for allopatric speciation

BackgroundAmblyomma cajennense F. is one of the best known and studied ticks in the New World because of its very wide distribution, its economical importance as pest of domestic ungulates, and its association with a variety of animal and human pathogens. Recent observations, however, have challenged the taxonomic status of this tick and indicated that intraspecific cryptic speciation might be occurring. In the present study, we investigate the evolutionary and demographic history of this tick and examine its genetic structure based on the analyses of three mitochondrial (12SrDNA, d-loop, and COII) and one nuclear (ITS2) genes. Because A. cajennense is characterized by a typical trans-Amazonian distribution, lineage divergence dating is also performed to establish whether genetic diversity can be linked to dated vicariant events which shaped the topology of the Neotropics.ResultsTotal evidence analyses of the concatenated mtDNA and nuclear + mtDNA datasets resulted in well-resolved and fully congruent reconstructions of the relationships within A. cajennense. The phylogenetic analyses consistently found A. cajennense to be monophyletic and to be separated into six genetic units defined by mutually exclusive haplotype compositions and habitat associations. Also, genetic divergence values showed that these lineages are as distinct from each other as recognized separate species of the same genus. The six clades are deeply split and node dating indicates that they started diverging in the middle-late Miocene.ConclusionsBehavioral differences and the results of laboratory cross-breeding experiments had already indicated that A. cajennense might be a complex of distinct taxonomic units. The combined and congruent mitochondrial and nuclear genetic evidence from this study reveals that A. cajennense is an assembly of six distinct species which have evolved separately from each other since at least 13.2 million years ago (Mya) in the earliest and 3.3 Mya in the latest lineages. The temporal and spatial diversification modes of the six lineages overlap the phylogeographical history of other organisms with similar extant trans-Amazonian distributions and are consistent with the present prevailing hypothesis that Neotropical diversity often finds its origins in the Miocene, after the Andean uplift changed the topology and consequently the climate and ecology of the Neotropics.

Confirmation of the presence of Amblyomma triste Koch, 1844 (Acari: Ixodidae) in Mexico

Abstract The following Mexican ticks labeled as Amblyomma triste Koch, 1844, were found in the Colección Nacional de Ácaros, Instituto de Biología, Universidad Nacional Autónoma de México: 4 males (M) and 4 females (F), ex cattle, Jun. 19, 1975, Las Pilas (28°49′N 102°00′W), Múzquiz, Coahuila; 1 M and 1 F, host, date and locality as above; 1 M, ex undetermined deer, Oct. 18, 1976, Yécora (28°22′N 108°56′W), Sonora. Both localities are in the Nearctic Zoogeographic Region. The ticks were confirmed as A. triste, thereby corroborating previous statements concerning the presence of this tick in Mexico. The current known distribution of A. triste includes the Neotropical and the Nearctic Zoogeographic Regions. Amblyomma triste is classified in the subgenus Anastosiella Santos Dias, 1963, whose members are difficult to differentiate in any stage. It is hoped that conventional and molecular taxonomic studies of Anastosiella species will help to clarify their range and phylogenetic relationships.

Parasites of Tadarida brasiliensis mexicana (Chiroptera: Molossidae) from Arid Regions of Mexico

Abstract Ninety-eight Mexican free-tailed bats, Tadarida brasiliensis mexicana, collected from 4 locations in Mexico between November 1996 and June 1998, were examined for metazoan parasites. Twenty-one parasitic taxa belonging to 3 phyla (Plathyhelminthes, Nematoda, and Arthropoda) were recovered including 5 helminth taxa (3 digenean, 1 cestode, and 1 nematode) and 16 arthropod taxa (12 mite, 2 tick, and 2 insect). The digenean Ochoterenatrema labda was the most prevalent and abundant helminth in collections from the states of Puebla, Zacatecas, and Durango. Urotrema scabridum and Dicrocoelium rileyi reached the highest values of prevalence and mean abundance of infection in Nuevo León state. Among arthropod taxa recovered, Chiroptonyssus robustipes was the most prevalent and abundant parasite in all 4 localities, and its nymphal stage was the most abundant form recovered. In total, 10 new host and 43 locality records are presented.

The Dermacentor (Acari, Ixodida, Ixodidae) of Mexico: hosts, geographical distribution and new records

Abstract Distribution and host data from published literature and previously unpublished collection records are provided for all nine species of the Holarctic tick genus Dermacentor that are known to occur in Mexico, as well as two species that may occur there. Parasite-host and host-parasite lists are presented, together with a gazetteer of collection localities and their geographical coordinates.

Pterygodermatites (Paucipectines) baiomydis n. sp. (Nematoda: Rictulariidae), a parasite of Baiomys taylori (Cricetidae)

Pterygodermatites (Paucipectines) baiomydis n. sp., an intestinal parasite of the northern pygmy mouse, Baiomys taylori (Cricetidae), collected in La Yerbabuena, Colima, Mexico, is described herein. Specimens were studied using light and scanning electronic microscopy. This is the 19th species of the subgenus Paucipectines described worldwide and the fourth collected in Mexico. It is differentiated from the remaining species in the subgenus by having 25 perioral denticles, arranged in a triangle (seven on each lateroventral margin, and eleven on the dorsal margin), and 10 pairs of caudal papillae.

A New Species of the Genus Eudusbabekia (Acari: Prostigmata: Myobiidae) on Leptonycteris nivalis (Chiroptera: Phyllostomidae) in Central Mexico

Eudusbabekia provirilia new species was found on the bat Leptonycteris nivalis (Saussure) in the central part of Mexico. The female, male, protonymph, and larva are described and illustrated.

Rickettsia lusitaniae associated with Ornithodoros yumatensis (Acari: Argasidae) from two caves in Yucatan, Mexico

The genus Rickettsia includes obligate intracellular bacteria transmitted by several hematophagous arthropods such as ticks, fleas and sucking lice. In particular hard ticks (Ixodidae) have been cited as the main vectors of pathogenic rickettsiae in Mexico. However, there have been only two records of a single Rickettsia species associated with Mexican soft ticks (Argasidae). In this study, we searched for rickettsial DNA in argasid ticks (13 adults and eight nymphs of Ornithodoros yumatensis) from two bat caves in the state of Yucatan, Mexico. Additionally one larva collected in a cave from Chiapas, Mexico, and associated with Desmodus rotundus was used to corroborate the tick taxonomic determination. Of these, nine ticks (43%) yielded expected PCR products for the rickettsial gltA gene. These PCR-positive ticks were tested with additional PCR protocols targeting the rickettsial genes gltA, ompA and ompB. DNA partial sequences from these genes showed 99-100% identities with Rickettsia lusitaniae, an agent isolated from O. erraticus in Portugal, and closely related to R. felis and R. hoogstraalii. Based on the results from this study, the inventory of rickettsiae distributed in Mexico increases from six to seven species.

Acarine Infracommunities Associated with the Mexican Free-Tailed Bat, Tadarida brasiliensis mexicana (Chiroptera: Molossidae) in Arid Regions of Mexico

Abstract The Mexican free-tailed bat, Tadarida brasiliensis mexicana, is one of the most widely distributed bats, and its range includes the whole Mexican territory. Ectoparasites of this bat have been the subject of isolated reports, but no studies of its community ecology have been conducted. The acarine infracommunities associated with this bat were analyzed, comparing bat populations from three arid regions of Mexico: an abandoned factory in Nombre de Dios, Durango; a cave in Santiago, Nuevo León; and a church in Concepción del Oro, Zacatecas. The acarine infracommunity in Nuevo León’s bats exhibited the highest levels of diversity as reflected by a higher richness, a lower dominance, and a moderate and relatively homogeneous abundance in this locality in relation to the other two. This pattern is influenced by stable cave conditions relative to artificial habitats. Notwithstanding, further studies are required to determine whether or not different habitat conditions are a primary factor in the process of structuring the acari infracommunities.

A new species of pterygosomatid mite and its phylogenetic position within the genus Geckobiella (Acariformes: Prostigmata: Pterygosomatidae)

A new species of pterygosomatid mite, Geckobiella variabilis sp. nov. (Acariformes: Pterygosomatidae) is described based on adults (female and male) and a larva. This new mite species was collected from two species of lizards of the genus Sceloporus (Phrynosomatidae) from the coast of the Gulf of Mexico. Geckobiella variabilis sp. nov. is very close to Geckobiella harrisi and Geckobiella texana; this new species can be readily distinguished from G. harrisi by the presence of solenidion ω2 on tarsi I and solenidion ω on tarsi III and from G. texana by the spatulate setae on dorsum and lateral parts of idiosoma, the barbed genital setae (g1) and coxae III-IV located very close to the anogenital area. The phylogenetic position of G. variabilis sp. nov. within Geckobiella is discussed, and an identification key for all the species of the genus is provided. http://zoobank.org/urn:lsid:zoobank.org:pub:4063717E-F4EB-473D-8F7F-7451481D18A7

Molecular identification and description of the female of Nothoaspis reddelli (Ixodida: Argasidae) from a cave in southeastern Mexico.

Abstract: Nothoaspis reddelli Keirans and Clifford, 1975, was described from 3 males collected in Grutas de Xtacumbilxunaán, Campeche, Mexico, although females have remained undescribed for 37 yr. Recently adult females of this species were collected from Cueva de Villa Luz ( =  Cueva de las Sardinas, Cueva del Azufre), in Tapijulapa, Tabasco, Mexico. Here we present a morphological description of the female stage, together with 16S rDNA sequences that confirm the conspecificity of our female, male, and nymphal specimens. The female integument of the anterior portion of the dorsal surface is smooth (nothoaspis), appearing to consist of 3 large “subunits,” 1 anterior and 2 posterior, each with a small sublateral “subunit” on either side. The remaining dorsal covered integument is a cell-like configuration. The hood is large and bluntly rounded, and visible dorsally. The spiracular plate is oval. It possesses 1 pair of posthypostomal setae. The palpal trochanter has 1 pair of setae and a 5/5 hypostome decreasing to 4/4 at the apex. There is a single central pore at the base of the hypostome.