Fernando Alvarez-Padilla

• PhD
• Professor (Full) at National Autonomous University of Mexico

The rhythm of biodiversity loss vastly surpasses the number of new species described per year, with several taxa going extinct without us even knowing about their existence. After more than 250 years of traditional taxonomy, it is clear that the rate of biodiversity description and discovery needs to be improved. Molecular data has greatly increase...

A new caponiid genus, Aamunops gen. n., is described and its phylogenetic placement within Nopinae tested using a published morphological data matrix. This genus includes four species collected during three standardized inventories in the state of Veracruz, Mexico. All specimens were collected inside plots of oak forests and tropical wet forests fr...

The spider family Tetragnathidae Menge is a cosmopolitan, relatively well-studied spider clade with some members readily identifiable by their elongate chelicerae and/or their horizontal orb webs. It has four recognized subfamilies—Tetragnathinae, Metainae, Leucauginae, and the Australasian endemic Nanometinae—although many genera remain unassigned...

Spider community inventories have relatively well-established standardized collecting protocols. Such protocols set rules for the orderly acquisition of samples to estimate community parameters and to establish comparisons between areas. These methods have been tested worldwide, providing useful data for inventory planning and optimal sampling allo...

The genus Wulfila O. Pickard-Cambridge 1895 belongs to the family Anyphaenidae Bertkau, 1878, commonly called ghost spiders. Wulfila is endemic to the Americas and currently has 43 valid species; here we describe five new: Wulfila conchamonile spec. nov., W. xilitlensis spec. nov., W. luisi spec. nov., W. unguis spec. nov. and W. phantasma spec. no...

A faunistic inventory from an oak forest near Pico de Orizaba National Park revealed the presence of two new species of pseudoscorpions. Atherochernes breviductus sp. nov. of the family Chernetidae is represented by 286 mature specimens, and is the first record of this genus for the country; Serianus orizabensis sp. nov. of the family Garypinidae i...

Seven new species of the genus Chrysometa Simon are described: C. citlaltepetl n. sp., C. triangulosa n. sp., C. rosarium n. sp., C. atotonilco n. sp., C. xamaticpac n. sp. C. puya n. sp. and C. sagicuta n. sp. Species identities were evaluated and sexes for each species matched with a fragment of the cytochrome c oxidase subunit I. These data were...

Three new hahniid species, Hahnia quadriseta sp. nov., Neoantistea multidentata sp. nov. and N. aspembira sp. nov., are described from a total of 1,131 individuals collected during spider inventories in Veracruz, Mexico. All specimens were collected inside four plots of Quercus forest, from leaf litter using active searching, sifted litter processe...

We present a phylogenetic analysis of spiders using a dataset of 932 spider species, representing 115 families (only the family Synaphridae is unrepresented), 700 known genera, and additional representatives of 26 unidentified or undescribed genera. Eleven genera of the orders Amblypygi, Palpigradi, Schizomida and Uropygi are included as outgroups....

The diversity of araneomorph spiders in an ecoturistic tropical forest remnant of approximately 40ha is described. A 1-ha plot with homogeneous vegetation was established. Six sampling methods covered all microhabitats, except tree canopy. Four expeditions were conducted from August 2011 to June 2012. In a total of 485 samples, 4,118 adult specimen...

Three new species of the spider genus Trachelas L. Koch, 1872 are described and included in the speciosus group based on the following features: embolus as a separate sclerite from the tegulum with no basal coils, legs with a conspicuous fringe of long trichobothria and narrow copulatory ducts coiled irregularly. The new species described are: T. c...

Reproduction in arthropods is an interesting area of research where intrasexual and intersexual mechanisms have evolved structures with several functions. The mating plugs usually produced by males are good examples of these structures where the main function is to obstruct the female genitalia against new sperm depositions. In spiders several type...

Four new species of oonopid spiders are described from Madagascar, divided between the genera Silhouettella and Noideattella: S. perismontes, sp. nov., S. perisalma, sp. nov., N. omby, sp. nov., and N. sylvnata, sp. nov. A new diagnosis for Silhouettella is provided, its type species, S. curieusei, from the Seychelles is redescribed, and its morpho...

The male of Megacormus granosus is described for the first time and the female redescribed. A homology scheme proposed recently is applied to hemispermatophore structures. The specimens were collected in an oak forest from Pico de Orizaba Volcano at an average altitude of 2340 m. All adult males were collected by pitfall traps, whereas all adult fe...

Two new genera of goblin spiders from Madagascar, Noideattella, new genus, and Tolegnaro, new genus, are described with 11 and two species respectively. Noideattella includes N. assumptia, new combination (transferred from Silhouettella), and 10 new species: N. amboa, N. famafa, N. fantara, N. farihy, N. gamela, N. lakana, N. mamba, N. saka, N. tan...

Based on a survey of a wide variety of oonopid genera and outgroups, we hypothesize new synapomorphies uniting the Oonopidae (minus the South African genus Calculus Purcell, which is transferred to the Orsolobidae). The groundplan of the tarsal organ in Oonopidae is hypothe sized to be an exposed organ with a distinctive, longitudinal ridge origina...

In order to study the tempo and the mode of spider orb web evolution and diversification, we conducted a phylogenetic analysis using six genetic markers along with a comprehensive taxon sample. The present analyses are the first to recover the monophyly of orb-weaving spiders based solely on DNA sequence data and an extensive taxon sample. We prese...

The present atlas documents the morphology of representative species of 22 tetragnathid genera, with emphasis on nontetragnathines. It includes approximately 960 scanning electron micrographs, morphological drawings and web photographs. The 213 characters used in the phylogenetic analyses are described and illustrated. We discuss the optimal cladog...

The spider genus Atelidea Simon, 1895 previously included two described species, A. spinosa Simon, 1895 and A. globosa Yamaguchi, 1957. In this study we describe for the first time the female of A. spinosa, and provide illustrations and scanning electron microscope images of external and internal features. The phylogenetic placement of this genus w...

The genus Atimiosa Simon, 1895, is a junior synonym of Dolichognatha O. P.-Cambridge, 1869. This synonymy is strongly supported by cladistic analyses of morphological characters and examination of types of all known Atimiosa species. Two new combinations resulted from this nomenclatural change, Dolichognatha comorensis (Schmidt and Krause, 1993), n...

The monophyly of Tetragnathidae including the species composition of the family (e.g., Are Nephila and their relatives part of this lineage?), the phylogenetic relationships of its various lineages, and the exact placement of Tetragnathidae within Araneoidea have been three recalcitrant problems in spider systematics. Most studies on tetragnathid p...

Exploring a large number of parameter sets in sensitivity analyses of direct optimization parsimony can be costly in terms of time and computing resources, and there is little a priori guidance available for reasonable limits to these search parameters. For this reason, we sought a general-purpose upper limit for gap costs in the direct optimizatio...

Examination of the holotype of the tetragnathid spider Sternospina concretipalpis Schmidt & Krause, 1993 demonstrates that the extraordinary claim by the authors of the original description of this species that the male palps are fused is unfounded. The monotypic genus Sternospina Schmidt & Krause, 1993 is a junior synonym of Tylorida Simon, 1894 a...

Examination of the holotype of the tetragnathid spider Sternospina concretipalpis Schmidt & Krause, 1993 demonstrates that the extraordinary claim by the authors of the original description of this species that the male palps are fused is unfounded. The monotypic genus Sternospina Schmidt & Krause, 1993 is a junior synonym of Tylorida Simon, 1894 a...

We describe a simple protocol for digesting the internal soft tissues of spiders using an enzyme complex known as pancreatin. This technique is preferred over digestions with caustic agents because it better preserves the cuticle surface, allowing its study by means of scanning electron or transmitted light microscopy. In addition, we describe a te...

The spider genus Metabus (Tetragnathidae) previously included nine species: the type M. gravidus O. P.-Cambridge, 1899 – junior synonym of Leucauge ocellata (Keyserling) – from Central America and eight species from Chile. In this paper, the classification of the Metabus species-complex is revised, and two new genera, with three new species and fiv...

The female genital morphology of the spiders in the araneoid genus Agriognatha (Tetragnathidae) is described and illustrated. The female genitalia of Agriognatha is characterized by a strong reduction of the sperm storage organs (spermathecae) and by the presence of a specialized distal compartment of the median membranous chamber that functions as...

A new species of ochyroceratid spider, Ochyrocera cachote, n.sp., is described and its unique web architecture is documented. This is the first record of Ochyroceratidae for the extant fauna of Hispaniola. Additional new family records include Symphytognathidae (Patu sp. and Symphytognatha sp.) and Mysmenidae (Microdipoena sp.), with the latter fam...

We review the systematics of the tetragnathid spider genus Sancus Tullgren, hitherto known from a single species from Kilimanjaro. The type species Sancus bilineatus Tullgren is redescribed and diagnosed from the only other known species, S. acoreensis (Wunderlich) new combination. Leucognatha Wunderlich is a junior synonym of Sancus, which thus el...