Neotyphloceras crassispina hemisus Jordan is redescribed from male and female specimens collected at the type locality (Otro Cerro, Catamarca Province, Argentina) and nearby localities. New diagnostic morphological characters for both sexes are provided, which include the shape of the upper lobe of the fixed process of clasper, the crochet of the aedeagus and the shape and chaetotaxy of the distal arm of sternum IX for males, and the contour of the distal margin of sternum VII for females.

: Laelapine mites are common parasites of sigmodontine rodents in the Neotropics. However, few species are reported from Peru as a result of the low number of mammal surveys that include ectoparasite collections. Herein we report 12 species of mites from northern Peru. From these, 8 are reported for the first time for the country, and 1 is new to science , Androlaepaps aerosus sp. nov., the latter associated exclusively with the sigmodontine Akodon aerosus . Most of the laelapine species were host specific. The new species, included in the Androlaelaps rotundus species group, resembles An. rotundus “sensu stricto” and An. ulysespardinasi in general appearance but is unique in the length of the hypostomal seta h3 (>58 μm), which is 3 times as long as the gnathosomal seta, and its tip reaching or over-reaching the gnathosomal setal bases; dorsal seta j2 is very long (>70 μm), almost reaching the point of j3 .

abstract The genus Nonnapsylla Wagner, 1938 (Craneopsyllinae) includes only 1 species, Nonnapsylla rothschildi Wagner, 1938 . Two subspecies are recognized by the shape of the dorsal margin of the helmet, apical shape of the spines in helmet and genal combs, length of first and fourth segments of the maxillary palpus, and shape of the hilla of the spermatheca. The validity of the characters used to separate the 2 subspecies of Nonnapsylla rothschildi Wagner, 1938 is discussed based on information from the literature, as well as from direct observation of type specimens and specimens collected in northwestern Argentina. We conclude that Nonnapsylla rothschildi wagneri Johnson, 1957 should be considered as a synonym of the nominal subspecies. We also extend the southern limits of the distribution of the species and report its presence in Argentina.

abstract Androlaelaps ulysespardinasi , a new species of laelapid mite, is described based on specimens collected from the pelage of the akodontine rodent Akodon philipmyersi Pardiñas, D'Elía, Cirignoli and Suarez, 2005 , which is endemic to the Northern Campos Grasslands in Misiones Province, Argentina. The formal taxonomic description, illustrations, and scanning electron micrographs of the new species are derived from female specimens; males and nymphs are unknown. Androlaelaps ulysespardinasi resembles Androlaelaps rotundus Fonseca, 1936 in general appearance, but it differs in having a more sclerotized, V-shaped and elevated ridge among j4 and j6 setae in the dorsal shield; the idiosoma is smaller (586–634 µm in length) and has a bilobed posterior margin. The sternal plate is 1.3 times broader than longer, the epigynial shield is 1.2 longer than broader, and an anal shield is almost as long as it is broad. Both species are close to Androlaelaps misionalis Lareschi, 2010 and Androlaelaps maurii Lareschi and Gettinger, 2009 , but they differ in their larger size (586–650 µm), in having the distance between j6 setae similar to the distance between j5 setae (72–83 µm), 11 pairs of setae in opisthogaster, and lacking a pair of setae close to epigynal shield. In addition, An. ulysespardinasi n. sp. is unusual in having chelicerae with both digits with 2 teeth. An An. rotundus species group, which includes the new species, is proposed, and a key to identify the different species is provided. Host specificity of the different species with rodents from the Akodon division of the akodontines was observed, suggesting that cophylogeny between these mites and akodontines may have occurred.

Androlaelaps maurii , a new species of laelapine mite, is described on the basis of female specimens collected from the pelage of the akodontine rodent, Deltamys kempi , from La Plata River basin in Argentina. Androlaelaps maurii can be differentiated from closely related species by its smaller size, the differing distribution of setae in the dorsal shield, and an unarmed opithogaster. This mite appears to be host specific to D. kempi and occurs on this rodent throughout its distribution in Argentina and Uruguay.

An intensive survey of ectoparasitic arthropods associated with small mammals in upland forests near Manaus, Brazil, provides information on the taxonomy and host distribution of laelapine mites in the Amazonian Region. We identified 5 genera and 21 species of these mites by comparison with representative museum specimens, the taxonomic literature, and, when possible, the original type specimens. These mites are host specific, with associations ranging from strict monoxeny (18 species) to oligoxeny (1 species) and pleioxeny (2 species). Marsupials were infested with species of Androlaelaps , echimyid rodents with Tur , and sigmodontine rodents with Gigantolaelaps , Laelaps , and Mysolaelaps . Androlaelaps bergalloi , a new species of Laelapinae, is described from the pelage of the marsupial Monodelphis brevicaudata .

Density and age structure of lice collected from captured Scapteromys aquaticus rodents were studied to estimate the fecundity of Hoplopleura scapteromydis. The number of eggs with a visible embryo inside (E), nymphs (N), adult males (AM), and adult females (AF) were recorded for each rodent. For the ith rodent, the fecundity of H. scapteromydis, F(i), was estimated as F(i) = {[E(i) + N(i)]/2}/AF(i)/T, where T represents the period of preimaginal development (unknown and arbitrarily considered as T = 1), and the sex ratio of the preimaginal stages was supposed to be 1:1. In order to look for density-dependent effects, F(i) was plotted against AM(i), this being an independent estimation of infrapopulation density. The number of rodents suitable for AF and AM calculations was 38 (57% of the parasitized animals). Almost 95% had a low-to-moderate louse burden (1 < AM < 30) and were captured every season, whereas only 3% had a heavy (61 < AM < 70, captured in winter) or very heavy (AM > 80, captured in summer) louse burden. The extreme values of F were 0.63 and 18 (1.3 and 36 if both sexes were considered). High-to-moderate F-values (F > 5) were estimated in only 5 rodents that exhibited low louse density, whereas low F-values (F < 5) were found at all louse densities. Notwithstanding the tendency toward an inverse relationship between fecundity and infrapopulation density, the correlation was not significantly different from 0.