Panbiogeographical analysis of the genus Bomarea (Alstroemeriaceae)

Aim  A panbiogeographical analysis of the genus Bomarea was undertaken in order to determine generalized tracks and biogeographical nodes, and to evaluate the current distribution of the genus based on the available tectonic information and the biogeographical regionalization of Latin America.
Location  The Neotropical region from northern Mexico to northern Argentina, and the Nearctic and Andean regions.
Method  A total of 2205 records of 101 species were analysed, representing 95% of the species assigned to Bomarea . Localities were represented on maps and their individual tracks were drawn. Based on their comparison, generalized tracks were detected and mapped. Nodes were identified in the areas where different generalized tracks were superimposed.
Results  Five generalized tracks were recovered. One is located in the Eastern Central America and Western Panamanian Isthmus provinces (Caribbean subregion, Neotropical region), which was supported by three species of Central American distribution. The four remaining generalized tracks were located in South America, in the North Andean Paramo, Cauca and Puna biogeographical provinces. These tracks were supported by species of Bomarea with an Andean distribution. Biogeographical nodes were established in the Central Andean region of Colombia, central Ecuador and central Peru.
Main conclusions  The nodes obtained for Bomarea support a hybrid origin for the Andean region, which presents diverse components from both northern and southern South America. Likewise, the track recovered between Colombia and Ecuador includes Andean and Neotropical areas, providing further support for this hypothesis. The nodes obtained are coherent with vicariant elements evident for Bomarea. Species of three clades proposed for Bomarea are distributed in specific generalized tracks.     

中国动物地理亚区繁殖鸟类地理分布格局与时空变化

以中国动物地理亚区统计了1976年郑作新出版的《中国鸟类分布名录》和2005年郑光美主编出版的《中国鸟类分类与分布名录》中繁殖鸟类的分布数据,结果显示:在1976年前,中国鸟类丰富度最高的动物地理亚区为西南山地亚区,其次为滇南山地亚区,而以羌塘高原亚区鸟类物种丰富度最低,黄淮平原亚区次差。2005年,鸟类丰富度最高、次高及最低的亚区与1976年相同,次差的亚区为台湾亚区。自1976年至2005年,鸟类物种丰富度在不同亚区出现明显的增加,平均每个亚区分布物种数由1976年的232种增至2005年的281种,而且具有很大的相关性;其中滇南山地亚区增加种类最多,而羌塘高原亚区和东部草原亚区增加的幅度最大;在海南岛和台湾亚区则变化较小。这些可能是由于物种在不同亚区间存在的可能扩散通道和岛屿型稳定气候及地理隔离限制了物种与其它亚区间的扩散等造成的。这些变化不仅与Leietal.(2007)提出的"地理隔离"假设结论比较一致,与雷富民等(2006)提出的西南山地-横断山区为中国鸟类特有种物种多样性中心和西南山地为物种分化中心等观点一致,而且进一步显示西南山地亚区鸟类物种有向滇南山地亚区扩散的现象,并且依然在持续中。用聚类...     

A hierarchical classification of freshwater mussel diversity in North America

Aim North America harbours the most diverse freshwater mussel fauna on Earth. This fauna has high endemism at the continental scale and within individual river systems. Previous faunal classifications for North America were based on intuitive, subjective assessments of species distributions, primarily the occurrence of endemic species, and do not portray continent‐wide patterns of faunal similarity. The aim of this study is to provide an analytical portrayal of patterns of mussel diversity in a hierarchical framework that informs the biogeographical history of the fauna. Location The study considered the mussel fauna of North America from the Rio Grande system northwards. Methods Patterns of mussel faunal similarity in 126 river systems or lake watersheds across North America were examined. The dataset was developed from the literature and consisted of recent species presence/absence (282 species) in each drainage unit; subspecies were not included. Patterns of mussel diversity were examined with hierarchical cluster analysis, based on a pairwise distance matrix between all drainage units. Results Cluster analysis revealed 17 faunal provinces within four major faunal regions: Mississippian, Atlantic, Eastern Gulf and Pacific. The Mississippian Region dominates the North American fauna with 11 provinces, including five not recognized by previous classifications: Mississippi Embayment, Upper Mississippi, Great Plains, Ohioan and Pontchartrain–Pearl–Pascagoula. Within the Eastern Gulf Region (containing three provinces), the Escambia–Choctawhatchee Province is distinctive from the Apalachicolan Province, under which it was previously subsumed. Patterns of diversity in the Atlantic Region (two provinces) and Pacific Region (one province) were similar to previous classifications. Main conclusions The classification proposed in this study largely corroborates earlier schemes based on the occurrence of endemic species but identifies additional heterogeneity that reflects unique assemblages of widely distributed species. The study proposes a hierarchical structure that illustrates relationships among these provinces. Although some provinces in the Mississippian Region have high endemism, all Mississippian provinces share a group of widely distributed species. The Atlantic and Eastern Gulf regions have distinctive, endemic faunas suggesting limited past connectivity with the Mississippian Region. The Pacific Region is the most distinct fauna in North America and bears close affinity to the Eurasian mussel fauna.     

Parsimony analysis of endemicity as a panbiogeographical tool: an analysis of Caribbean plant taxa

To demonstrate that parsimony analysis of endemicity (PAE) can be a method implementing the panbiogeographic approach, we analyzed two data matrices of 40/38 biogeographic provinces × 148 plant species from the Caribbean subregion of the Neotropical region, one where taxa are represented by individual tracks and the other where taxa are represented by single sample localities. We obtained six generalized tracks resulted from the PAE of the areas × individual tracks matrix, and one generalized track from the PAE of the areas × single sample localities matrix, with the latter nested within the former tracks. The results obtained show that PAE works as a panbiogeographical tool if it is based on an areas × individual tracks matrix. When performed in this way, PAE retrieves spatial information that is lost when it is based on an areas × single sample localities matrix, raising doubts regarding the conclusions derived from this latter type of analysis. © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 101 , 961–976.     

Insular Freshwater Fish Faunas of Micronesia: Patterns of Species Richness and Similarity

Freshwater fishes are an important but relatively little known component of the highly diverse fish fauna of Micronesia. Localities supporting communities of freshwater fishes include large high islands, with considerable habitat complexity, and smaller low islands, such as atolls and raised coral islands, with limited freshwater habitat. Both types of islands may support species with adult life history styles that are (a) amphidromous and catadromous, (b) euryhaline (often estuarine), or (c) marine species which enter freshwater from time to time. We compared patterns of species richness and similarity between Micronesian localities for amphidromous and catadromous, euryhaline and marine species (ACEM) pooled, and for amphidromous and catadromous species (ACFW). Species richness of both ACEM and ACFW fishes was greatest on larger high islands compared to smaller high and all low islands. Cluster analysis of similarity indices for ACEM species between localities revealed two faunal components: high islands and low islands. High islands were further partitioned into a Caroline Islands cluster and a separate Mariana Islands cluster. Cluster analysis of ACFW species was more complex. One cluster consisted of a low island and a small high island, both in the Carolines chain and with limited freshwater habitat. The second cluster was partitioned into high islands and low islands that reflected influences of both size and geographical location.     

Panbiogeographical analysis of Costa Rican freshwater fishes

Track analysis and Parsimony analysis of endemicity (PAE) were performed to analyze the distribution pattern of Costa Rican freshwater fishes. A basic matrix (presence/absence) was prepared using the distribution of 77 freshwater fish. The data were analyzed with CLIQUE software in order to find generalized tracks (cliques). Data also were analyzed with the software NONA and Winclada version 1.00.08 in order to perform the Parsimony Analysis of Endemicity (PAE). Fourteen equally probable cliques were found with 31 species in each and the intersection of the amount was selected as a generalized track dividing the country in two main zones: Atlantic slope from Matina to Lake Nicaragua and Pacific slope from the Coto River to the basin of the Tempisque River connected with some branches oriented to the central part of the country. PAE analysis found ten cladogram areas (72 steps, CI=0.45, RI=0.64), using the "strict consensus option" two grouping zones were identified: Atlantic slope and Pacific slope. Both PAE and Track Analysis show the division of the two slopes and the orientation of the generalized track suggests new biogeographical evidence on the influence of both old and new southern elements to explain the migrations of freshwater fish into Central America during two different geological events.     

中国斑叶蝉族昆虫地理分布格局聚类分析

分析了斑叶蝉族昆虫在中国以及贵州动物地理区的分布情况,探讨其分布格局形成、起源和演化原因。根据中国和贵州斑叶蝉族的地理分布数据,运用MEGA 6.0、SPSS 22.0和ArcGIS 10.2等软件,对斑叶蝉族昆虫的区及亚区分布进行支序聚类分析,结果表明我国斑叶蝉族现代分布中心为西部山地高原亚区、华南区的台湾亚区及滇南山地亚区,分布热点地区为西双版纳地区、海南地区和台湾地区。贵州斑叶蝉现代分布中心为黔东低山丘陵省、黔北中山峡谷省和黔南低山河谷省,分布热点地区为铜仁北部的沿河地区、遵义的务川地区及贵州黔东南州的榕江、雷山地区。斑叶蝉族昆虫中国分布区形成的顺序先是东北区,其次是青藏区和蒙新区,最后是西南区、华北区、华南区和华中区。贵州分布区形成的顺序先是黔西高原中山省和黔中山原丘陵省,其次是黔南低山河谷省,最后是黔北中山峡谷省和黔东低山丘陵省。中国分布区中,B21和B22聚类群属级阶元的相似性最高,区间关联性最强。在贵州分布区中黔东低山丘陵省和黔北中山峡谷省属级阶元的相似性最高,物种交流最为频繁。目前,斑叶蝉族昆虫的地理分布格局主要是历史气候变化、当前气候条件以及植被覆盖等生态环境共同作用的结果;区系起源和演化主要受地质构造运动作用;斑叶蝉在各区的分布相似性可能与气候变化引起的物种由南向北扩散有关。     

The distribution of the ectoparasite fauna of Sebastes capensis from the southern hemisphere does not correspond with zoogeographical provinces of free-living marine animals

Aim We examined the ectoparasite fauna of Sebastes capensis over almost all its geographical distribution range (Chilean, Argentinean and South African coasts) to determine (1) whether the ectoparasites of this host show a zoogeographical pattern and, if so, (2) how this pattern is related to known zoogeographical patterns for free‐living organisms. Location Fish were captured from 20, 24, 30, 33, 36, 40, 45 and 52° S along the Chilean coast; 11° S on the Peruvian coast; 43° S on the Argentina coast; and 34° S on the South African coast. Methods From April to September 2003 and from April to August 2004, 626 fish were captured. The parasites were collected using standard parasitological techniques. At the component community level, zoogeographical distribution patterns were evaluated using cluster analysis. At the infra‐community level, patterns of similarity in parasite composition among localities were investigated with multivariate discriminant analyses. Results The ectoparasite fauna of S. capensis consists of six species distributed along the whole of the Chilean coast. Four other species are distributed only within the transitional zone between the northern warm temperate region (Peruvian faunistic province), extending from Peru to the northern Chilean coast up to c. 30° S, and the cold temperate region (Magellanic faunistic province). The component communities from latitudes 30 to 40° S showed higher ectoparasite species richness, while localities on the margins of the geographical range showed lower species richness. Cluster analysis indicated a grouping of localities consistent with the transitional zone. Argentina and South Africa always emerged as separate localities. Main conclusions The ectoparasite communities of S. capensis do not follow a distributional pattern concordant with the known biogeographical zones for invertebrates and/or fish along the south‐eastern Pacific. Therefore their ectoparasite fauna is not useful as a zoogeographical indicator, although it does allow us to distinguish the transitional zone of the south‐eastern Pacific. On a more extended geographical scale, it is possible to distinguish the ectoparasite communities of S. capensis in the south‐eastern Pacific (as a whole) from those of Argentina and South Africa.     

A delineation of Nuclear Middle America biogeographical provinces based on river basin faunistic similarities

The biogeographical patterns of the obligate freshwater fishes of Nuclear Middle America, a region that expands from southern Guatemala to northern Nicaragua, are described herein. Historically, three broad ichthyological provinces have been assigned to Nuclear Middle America: the Usumacinta, and the San Juan in the Atlantic slope and the Chiapas-Nicaragüense in the Pacific slope. With the use of correspondence analysis and unweighted pair group method with arithmetic mean cluster analysis of a presence/absence matrix of 76 obligate freshwater fishes, we identified four ichthyological provinces in Nuclear Middle America: (1) the Honduras and Guatemala Caribbean Highlands Province, (2) the Honduras and Nicaragua Mosquitia Province, (3) the Chiapas-El Salvador-Nacaome Province, and (4) the Choluteca and Nicaragua Pacific Province. Differences between provinces in species composition and species turnover between provinces were tested by analysis of similarity, the calculation of beta-diversity indices and an indicator species analysis. We then further characterized each province by identifying the number of endemics and classifying species according to their salinity tolerance. The most striking patterns of Nuclear Middle America freshwater fish distribution are its paucity of primary freshwater fishes and limited numbers of endemics. The four ichthyological provinces are distinct as indicated by the ANOSIM and beta-diversity analysis, although one province showed low beta-diversity values. These results suggest that, despite of the active geological history that characterized the region, there has been limited isolation of species in any given province, and historical drainage connectivity has been high.     

A revision of the bioregionalisation of freshwater fish communities in the Australian Monsoonal Tropics

The Australian freshwater fish fauna is very unique, but poorly understood. In the Australian Monsoonal Tropics (AMT) biome of northern Australia, the number of described and candidate species has nearly doubled since the last attempt to analyse freshwater fish species composition patterns and determine a bioregionalisation scheme. Here, we utilise the most complete database of catchment‐scale freshwater fish distributions from the AMT to date to: (a) reanalyze spatial patterns of species richness, endemism and turnover of freshwater fishes; (b) propose a biogeographic regionalisation based on species turnover; (c) assess the relationship between species turnover and patterns of environmental change and historic drainage connectivity; and (d) identify sampling gaps. Biogeographic provinces were identified using an agglomerative cluster analysis of a Simpson's beta (β_sim) dissimilarity matrix. A generalised dissimilarity model incorporating eighteen environmental variables was used to investigate the environmental correlates of species turnover. Observed and estimated species richness and endemism were calculated and inventory completeness was estimated based on the ratio of observed to estimated species richness. Three major freshwater fish biogeographic provinces and 14 subprovinces are proposed. These differ substantially from the current bioregionalisation scheme. Species turnover was most strongly influenced by environmental variables that are interpreted to reflect changes in terrain (catchment relief and confinement), geology and climate (runoff perenniality, stream density), and biotic responses to climate (net primary productivity). Past connectivity between rivers during low sea‐level events is also influential highlighting the importance of historical processes in explaining contemporary patterns of biodiversity in the AMT. The inclusion of 49 newly discovered species and candidate species only reinforced known focal points of species richness and endemism in the AMT. However, a number of key sampling gaps remain that need to be filled to fully characterise the proposed bioregionalisation.     

Galaxitaenia toloi n. gen., n. sp. (Eucestoda: Pseudophyllidea) from Galaxias platei (Pisces: Osmeriformes, Galaxiidae), in the Patagonian region of Argentina

Galaxitaenia n. gen. (Eucestoda: Pseudophyllidea) is proposed to accommodate Galaxitaenia toloi n. gen., n. sp. from Galaxias platei, a freshwater fish inhabiting Andean lakes in Argentine Patagonia. Galaxitaenia belongs to the Triaenophoridae because it possesses a marginal genital pore, a ventral uterine pore, and a follicular vitelline gland. The new genus can be distinguished from other triaenophorids by the following combination of characters: a scolex with a prominent rectangular apical disc without hooks, grooves, or indentations; neck present; segments wider than long to quadrangular; testes in 2 lateral fields, often connected anteriorly; cirrus unarmed; an ovary situated posteriorly; a vagina posterior to the cirrus sac; vitelline follicles medullary, in 2 ventral fields forming 2 wings interrupted medially; a uterus saccate to branched; and eggs without operculum. The types, distribution, and density of microtriches were analyzed on the surface of the tegument of scolex, neck, and immature segments. The presence of tumuli were observed on the apical disc of the scolex. Galaxitaenia toloi n. sp. is the first triaenophorid species recorded in a South American freshwater fish and the fourth helminth parasitizing the intestine of G. platei.     

Molecular phylogeography of the Chagas' disease vector Triatoma infestans in Argentina

Triatoma infestans is the main vector of Chagas' disease in South America between latitudes 10°S and 46°S. A multilocus microsatellite data set of 836 individuals from 27 populations of T. infestans, from all its range of distribution in Argentina, was analyzed. Our results favor the hypothesis of two independent migration events of colonization in Argentina and secondary contacts. The majority of the populations of the western provinces of Catamarca, La Rioja, San Juan and the west of Cordoba province, had almost no shared ancestry with the rest of the populations analyzed. Probably those populations, belonging to localities close to the Andean region, could have been established by the dispersal line of T. infestans that would have arrived to Argentina through the Andes, whereas most of the rest of the populations analyzed may have derived from the dispersal line of T. infestans in non-Andean lowlands. Among them, those from the provinces of Formosa, Chaco, Santiago del Estero and Santa Fe shared different percentages of ancestry and presented lower degree of genetic differentiation. The migratory movement linked to regional economies and possibly associated with passive dispersal, would allow a higher genetic exchange among these populations of T. infestans. This study, using microsatellite markers, provides a new approach for evaluating the validity of the different hypotheses concerning the evolutionary history of this species. Two major lineages of T. infestans, an Andean and non-Andean, are suggested.     

Angiosperm flora and biogeography of the páramo region of Colombia,Northern Andes

Páramo is the neotropical high elevation ecosystem in the northern Andes and Central America consisting of multiple dissected open areas above 3000 m a.s.l. Complex evolutionary processes that occurred within these ecosystems gave rise to a unique tropical Andean flora. Previous phytogeographical classifications for Colombian páramos have been based on subjective assessments of species distributions. However, a detailed floristic analysis highlighting affinities between páramo regions in Colombia has not yet been proposed. The aim of this study is to provide an analytical scenario for the patterns of regional plant diversity in a hierarchical framework based on the biogeographical history of the páramos, based on 30 localities of the Colombian páramos. Parsimony analysis of endemicity (PAE) and Jaccard similarity indices were applied to a presence/absence data matrix of páramo angiosperm species. Altitudinal distribution of species was used to determine the percentage of the páramo flora endemic to this ecosystem. Genera are shared among páramos, whereas species composition is highly endemic. 86% of the páramo angiosperm plant species is endemic to this ecosystem. The Colombian Páramo areas can be grouped using PAE into five biogeographical units, based on angiosperm species composition. These are: (1) Páramos de la Cordillera Oriental; (2) Páramos de la Cordillera Central and Macizo Colombiano; (3) Páramos de Antioquia; (4) Páramos del Norte; (5) Páramos de la Cordillera Occidental.     

Application of parsimony analysis of endemicity to Mexican gymnosperm distributions: grid-cells, biogeographical provinces and track analysis

Parsimony analysis of endemicity (PAE) was used to analyse the distributional patterns of 124 species of Mexican gymnosperms, using two different sample units: grid-cells and biogeographical provinces. PAE analyses were based on distributional data from herbarium specimens and specialized literature. Two data matrices were constructed for 60 grid-cells of 2° and 14 biogeographical provinces. The analysis of the 2° grid-cell matrix led to 7084 cladograms. The strict consensus cladogram showed several clades equivalent to the results obtained with the biogeographical provinces. Three clades agree with some principal regions of distribution of Mexican pines, previously identified by several authors, located at the northern portion of the Baja California peninsula, the Sierra Madre Occidental, and the Sierra Madre Oriental. These areas represent important centres of species diversity and endemism for Mexican gymnosperms. The analysis of the province matrix led to two most parsimonious cladograms, which only differed in the position of the Sierra Madre Occidental province. The iterative procedure PAE with progressive character elimination was applied to identify generalized tracks, where clades of provinces were considered equivalent to generalized tracks, and each time a cladogram was obtained, species defining its clades were deleted and a new run was undertaken. We found five generalized tracks, mainly located in montane provinces. The distribution patterns of gymnosperms agree with the existence of several Mexican biogeographical provinces, and a different historical biogeography of the Mexican peninsulas from the rest of the country is evident.  © 2007 The Linnean Society of London, Biological Journal of the Linnean Society , 2007, 92 , 405–417.     

宁夏哺乳动物区系与地理区划研究

宁夏现有哺乳动物75种,隶属于6目19科52属 。本文分析了宁夏哺乳动物区系特征,将宁夏划分为3个动物地理省、6十动物地理州,并对各省及各州动物区系之间的相似性等问题进行了探讨。     

广西野生淡水鱼类的物种多样性及其资源的可持续利用

广西地形复杂,河流众多,适于不同鱼类的栖息和繁殖.经对分布于广西境内的各水系鱼类资源的调查、对相关馆藏标本的进一步鉴定以及对相关文献的整理,目前已知广西淡水鱼类15目37科143属290种和亚种,其中很多种类具有重要经济价值.对广西及其邻近省区鱼类多样性指数的计算、比较和分析表明,广西地区G指数最高,F指数和G-F指数除低于云南外,高于广东、海南、贵州和湖南.广西野生淡水鱼类的显著特点是物种多样性高,特有属、种多,很多物种分布区狭窄,区系成分表现出明显的东洋界特点,不同水系鱼类组成各具特色.近年来,广西自然水域的野生鱼类资源的破坏较为严重,本文对广西野生淡水鱼类资源的可持续利用进行了讨论.     

Distribution and Abundance of Opisthorchis viverrini Metacercariae in Cyprinid Fish in Northeastern Thailand

To increase public health awareness for prevention of opisthorchiasis caused by eating raw freshwater fish, the distribution and abundance of Opisthorchis viverrini metacercariae (OV MC) was investigated in freshwater fish obtained from 20 provinces in northeastern Thailand between April 2011 and February 2012. A cross-sectional survey was conducted on 12,890 fish consisting of 13 species randomly caught from 26 rivers, 10 dams, and 38 ponds/lakes. Fish, were collected in each of the rainy and winter seasons from each province. Fish were identified, counted, weighed, and digested using pepsin-HCl. Samples were examined for OV MC by a sedimentation method, and metacercariae were identified under a stereomicroscope. OV MC were found in 6 species of fish; i.e., Cyclocheilichthys armatus, Puntius orphoides, Hampala dispar, Henicorhynchus siamensis, Osteochilus hasselti, and Puntioplites proctozysron from localities in 13 provinces. Among the sites where OV MC-infected fish were found, 70.0% were dams, 23.7% were ponds/lakes, and 7.7% were rivers. The mean intensity of OV MC ranged from 0.01 to 6.5 cysts per fish (or 1.3-287.5 cysts per kg of fish). A high mean intensity of OV MC per fish (>3 cysts) was found in 5 provinces: Amnat Charoen (6.5 cysts), Nakhon Phanom (4.3), Mukdahan (4.1), Khon Kaen, (3.5) and Si Sa Ket (3.4). In conclusion, OV MC are prevalent in natural cyprinid fish, with the infection rate varying according to fish species and habitats.     

鱼类谷胱甘肽转移酶基因cDNA克隆及其序列分析

采用RT-PCR方法, 从鲢、鲤、鲫3种鱼类肝脏总RNA中克隆出了谷胱甘肽转移酶Pi型(GST Pi)cDNA序列, 推导了其编码的氨基酸序列。3种鱼类GST Pi的ORF全长627 bp, 编码208个氨基酸。翻译起始密码均为ATG, 终止密码子均为TGA。鱼类与哺乳动物、两栖类爪蟾以及节肢动物丝虫之间GST Pi氨基酸序列相似度平均值分别为50%、33%、15%左右。5种鱼类之间的氨基酸序列相似度较大, 其中鲤科鱼类之间平均为85%左右。我们以GST Pi为分子标记, 用最大简约数法(MP)构建了13个物种的系统进化树, 识别出两个大的单系类群: 哺乳类组成类群一(bootstrap 100); 鱼类组成类群二(bootstrap 93)。通过比较鱼类与哺乳类GST Pi N末端和C末端功能域的氨基酸组成差异,探讨了淡水鱼类GSTs承担较强的微囊藻毒素去毒能力的可能分子机制。     

Host range and geographical distribution of <Emphasis Type="Italic">Ixodes sigelos</Emphasis> (Acari: Ixodidae)

Larvae, nymphs and females of Ixodes sigelos Keirans, Clifford and Corwin (Ixodidae) were collected in 13 localities of the Patagonian region of Argentina parasitizing eight species of sigmodontine rodents. We report for the first time adults of I. sigelos for Argentina. Besides, we extend the southern limit of its geographical distribution, and six species of sigmodontines are added as new host species of I. sigelos (Phyllotis xanthopygus, Euneomys chinchilloides, Calomys musculinus, Reithrodon auritus, Loxodontomys micropus and Eligmodontia morgani). The presence of larvae, nymphs and females on sigmodontines, as well as more than 50% of the individuals engorged, indicate that I. sigelos can develop the complete parasitic phase of its life cycle on these small mammals. The geographical distribution of I. sigelos is restricted to the biogeographical Andean Region in Argentina and Chile.