The species of the genus Centroctenus can be distinguished from other Ctenidae genera by the presence of a long tibiae and the absence of a retrolateral projection of the cymbium in the male palp, and by the presence of a rounded spermathecae in the female epigynum. The composition of this spider genus is herein expanded to eleven Neotropical species, with the description of six new species: Centroctenus dourados sp. n., C. claudia sp. n., C. chalkidisi sp. n., and C. varzea sp. n., from Brazil; and Centroctenus coloso sp. n. from Colombia and Centroctenus alinahui sp. n. from Ecuador. A map with the distribution of all known species in the genus is presented.

The alpaca fiber diameter (FD) varies from 18 to 36 μm, being the finer fiber categories highly appreciated. However, the alpaca fiber presents some limitations in the textile industry due to the high incidence of fiber medullation and diameter variability, both reduces the comfort feeling of the garments. Decreasing or even removing medullation could be a possible selection objective in alpaca breeding programs for increasing economic value of the alpaca fiber. Therefore, the present work aimed to estimate genetic parameters regarding medullation traits, as well as the genetic correlations with other economical important traits, to be able to select the appropriate criteria to reduce or remove medullation on alpaca fiber and help to reduce the prickle factor in the garments. The data was collected from 2000 to 2017 and belonged to the Pacomarca experimental farm. There were 3698 medullation records corresponding to 1869 Huacaya and 414 Suri genetic types. The fiber samples were taken from the mid side, and were analyzed in an OFDA 100® device. The traits analyzed were percentage of medullation (PM), medullated fiber diameter (MFD), FD, standard deviation of FD, greasy fleece weight as fiber traits; density, crimp in Huacaya and lock structure in Suri, head conformation, leg coverage as morphological traits; weaning weight and age at first calving as secondary and functional traits. Genetic parameters were estimated via a multitrait restricted maximum likelihood. The heritabilities for PM and MFD were 0.225 and 0.237 in Huacaya genetic type and 0.664 and 0.237 in Suri genetic type, respectively; heritabilities for other traits were moderate for productive and morphological traits, and low to moderate for secondary and functional traits. The genetic correlations PM–FD and MFD–FD were high and favorable in both genetic types, between 0.531 and 0.975; the genetic correlation PM–MFD was 0.121 in Huacaya and 0.427 in Suri. The rest of genetic correlations with other traits were in general moderate and favorable. The repeatabilities were 0.556 and 0.668 for PM, and 0.322 and 0.293 for MFD in Huacaya and Suri genetic types, respectively. As a conclusion, PM was identified to be a good selection criterion, probably combined in an index with FD to reduce prickling factor.

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Variación morfogeométrica en Phrynus barbadensis (Pocock, 1893) (Amblypyghi: Phrynidae) de Colombia RESUMEN. Amblypygi es un pequeño orden de arácnidos con características similares a arañas. En Colombia, este orden ha sido poco estudiado, y la mayoría de las investigaciones se han centrado a niveles taxonómicos. Recientemente, la morfometría geométrica ha probado ser una herramienta útil para determinar diferencias en escorpiones y arañas. Debido a esto, utilizamos morfometría geométrica para determinar variación intraespecifica en tres poblaciones colombianas de Phrynus barbadensis. Digitalizamos 16 puntos anatómicos sobre el caparazón y 15 en la patela combinando hitos e hitos deslizantes; las coordenadas fueron analizadas mediante análisis generalizado de Procrustes. Se implementó el Análisis de Variables Canónicas con proporción de grupos reclasificados y MANOVA. Se determinaron diferencias significativas en la conformación del caparazón entre poblaciones; todos los especímenes fueron 80% correctamente clasificados. Los análisis estadísticos de varianza (ANOVA) determinaron diferencias significativas en los tamaños isométricos de caparazón y patela entre poblaciones. Las diferencias en el caparazón se asocian con los márgenes anterior, lateral derecho, y posterior. La variación observada podría asociarse a las diferencias ambientales entre localidades. PALABRAS CLAVE. Araña látigo. Conformación. Procrustes. Variación intraespecífica. ABSTRACT. Amblypygi is a small order of arachnids with features similar to spiders. In Colombia, this order has been subject to low attention, the main investigations are focused towards a taxonomic level. Recently, the geometric morphometrics has proven to be an useful tool for determining shape differences in scorpions and spiders. Due to this, we used geometric morphometrics to determine intraspecific variation in three Colombian populations of Phrynus barbadensis. We digitalized 16 anatomical points over the carapace and 15 in patella by combining landmarks and sliding semilandmarks; the coordinates were aligned by generalized Procrustes analysis. Canonical Variates Analysis was implemented with proportions of reclassified groups and MANOVA. We found significant differences of carapace conformation between populations; all specimens were 80% correctly classified. Statistical analyses of variance (ANOVA) found significant differences in carapace and patella isometric size among populations; the main carapace differences occur in anterior, posterior and right margins. The observed variation could be associated with the environmental differences between localities.

Aspectos de la historia natural de Phrynus barbadensis (Pocock, 1893) (Amblypygi: Phrynidae) RESUMEN. La información sobre las presas y los depredadores de los amblipígidos es escasa, en gran parte dispersa y, a veces, olvidada por el aracnólogo. Phrynus barbadensis es una araña látigo neotropical ampliamente distribuida, pero su historia natural es poco conocida. El objetivo principal de esta contribución se refiere a las presas, los depredadores, el esfuerzo reproductivo y las preferencias de microhábitats de P. barbadensis en una localidad colombiana. Dos investigadores llevaron a cabo el trabajo de campo durante cuatro expediciones de seis días cada una, entre junio y noviembre de 2017. Dos casos observados de depredación intragremial se relacionaron con la araña Scytodes longipes Lucas (Araneae: Scytodidae) y la araña látigo gigante Heterophrynus caribensis Armas, Torres-Contreras & Álvarez (Phrynidae: Heterophryninae). También se registra un nuevo caso de un molusco como presa de las arañas látigo. El número de embriones por lote en P. barbadensis fue 14-79 (n = 27, promedio = 40, error estándar = 3,83), teniendo una correlación positiva con el tamaño de la hembra. Esta especie estuvo altamente asociada a troncos caídos y rocas, pero pobremente a la hojarasca y las paredes rocosas (χ 2 = 16,26; P < 0,001); con respecto a la temperatura del sustrato, mostró una asociación positiva. El canibalismo y la necrofagia entre las arañas látigo son brevemente comentadas, y también se proporcionan listas actualizadas de las presas y depredadores conocidos de los amblipígidos.