Martín Ramírez

Martín Ramírez
Museo Argentino de Ciencias Naturales "Bernardino Rivadavia" · Division of Arachnology

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194
Publications
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Publications

Publications (194)
Article
The systematics of Philodromidae is far from complete, especially for the Neotropical genera. Among these, Petrichus Simon, 1886 is a poorly known genus restricted to arid and semi-arid environments of South America. In this work, we performed a total-evidence analysis to assess the phylogenetic relationships of Petrichus and revised the taxonomy....
Article
Modern methods of ancestral state estimation (ASE) incorporate branch length information, and it has been demonstrated that ASEs are more accurate when conducted on the branch lengths most correlated with a character’s evolution; however, a reliable method for choosing between alternate branch length sets for discrete characters has not yet been pr...
Article
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Filistatids, the crevice weavers, are an ancient family of cribellate spiders without extant close relatives. As one of the first lineages of araneomorph spiders, they present a complicated mixture of primitive and derived characters that make them a key taxon to elucidate the phylogeny of spiders, as well as the evolution of phenotypic characters...
Article
A prominent question in animal research is how the evolution of morphology and ecology interact in the generation of phenotypic diversity. Spiders are some of the most abundant arthropod predators in terrestrial ecosystems and exhibit a diversity of foraging styles. It remains unclear how spider body size and proportions relate to foraging style, a...
Article
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“Pioneers: Women Scientists of the Museo Argentino de Ciencias Naturales’’ is a cycle that began in March 2019 within the framework of the International Women’s Day. It began as an initiative of a self-convened group of working women of the Museum, with the aim of recognizing and honoring the trajectories of the first women who carried out scientif...
Article
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Spiders are a highly diversified group of arthropods and play an important role in terrestrial ecosystems as ubiquitous predators, which makes them a suitable group to test a variety of eco-evolutionary hypotheses. For this purpose, knowledge of a diverse range of species traits is required. Until now, data on spider traits have been scattered acro...
Article
The subfamily Nothopuginae is revised. Titanopuga salinarum gen. et sp. nov., Cuyanopuga bilobata gen. et sp. nov. and Nothopuga telteca sp. nov. are described. We performed a cladistic analysis based on 144 morphological characters and 24 terminals, including representatives of all ammotrechid subfamilies. Nothopuginae is recovered monophyletic wi...
Article
The importance of morphology in the phylogenomic era has recently gained attention, but relatively few studies have combined both types of information when inferring phylogenetic relationships. Sanger sequencing legacy data can also be important for understanding evolutionary relationships. The possibility of combining genomic, morphological and Sa...
Article
Aim Fossil data may be crucial to infer biogeographical history, especially in taxa with tropical trans-Pacific distributions. Here, we use extinct and extant trochanteriid flattened spiders to test hypotheses that could explain its trans-Pacific disjunct distribution, including a Boreotropical origin with a North Atlantic dispersal, an African ori...
Article
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Event-based biogeographic methods, such as dispersal-extinction-cladogenesis, have become increasingly popular for attempting to reconstruct the biogeographic history of organisms. Such methods employ distributional data of sampled species and a dated phylogenetic tree to estimate ancestral distribution ranges. Because the input tree is often a sin...
Article
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1. Major floods of riparian and grassland habitats may lead to a shift in the availability of resources (e.g., food, space) that produces cascading effects on the organisms that rely on it. After flooding occurs, particularly in natural grasslands or agricultural fields, massive aggregative spider webs are occasionally observed. However, given it i...
Article
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Zootaxa published more than a thousand papers on Araneae from 2002 to the present, including descriptions of 3,833 new spider species and 177 new genera. Here we summarise the key contributions of Zootaxa to our current knowledge of global spider diversity. We provide a historical account of the researchers that have actively participated as editor...
Preprint
Full-text available
Event-based biogeographic methods, such as dispersal-extinction-cladogenesis, have become increasingly popular for attempting to reconstruct the biogeographic history of organisms. Such methods employ distributional data of sampled species and a dated phylogenetic tree to estimate ancestral distribution ranges. Because the input tree is often a sin...
Article
Two new caeculid mite species, Andocaeculus beatrizrosso sp. nov. and Andocaeculus burmeisteri sp. nov., are described and A. weyrauchi (Franz, 1964) is redescribed based on material collected at the type locality. All post-larval stages are described for A. weyrauchi and Andocaeculus beatrizrosso sp. nov. and stochastic variation in the idiosomal...
Article
The genus Meriola Banks currently includes 24 known species of spiders distributed across America, especially in southern South America. They have a nearly straight and narrower posterior eye row compared to other American genera of Trachelidae, and elongated and sharply tipped ventral leg cuspules. The study of specimens of Meriola available in co...
Article
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Synopsis Spider web anchors are attachment structures composed of the bi-phasic glue-fiber secretion from the piriform silk glands. The mechanical performance of the anchors strongly correlates with the structural assembly of the silk lines, which makes spider silk anchors an ideal system to study the biomechanical function of extended phenotypes a...
Article
Morphological boundaries between species of the maculatipes‐group in the ghost spider genus Sanogasta Mello‐Leitão are ambiguous, and the most widespread species, S. maculatipes, is unusually variable and may represent multiple cryptic species. To resolve these issues, we perform a geometric morphometric analysis on the female genitalia of the grou...
Article
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Psilodercidae contains some 200 known extant species of small spiders that live in tropical rainforests and caves and is mainly restricted to the Oriental biogeographic realm. Interestingly, at least ten different fossil species have been described from inclusions in Late Cretaceous Burmese amber. This suggests the family has been diversifying in t...
Article
The first phylogenetic analysis of genus Urophonius is performed based on morphological characters. Three monophyletic species groups are recovered. Species of the granulatus species group and Urophonius mondacai have summer or spring activity patterns. The exochus and brachycentrus species groups form a monophyletic group with a winter activity pa...
Article
Variable retention mitigates negative effects of traditional harvesting on biodiversity, maintaining legacies in harvested forests as habitat for sensitive species, and generating other habitats for early-seral species. Their assessment, including drivers, has a high concern for society. Likewise, species association with ecosystems in the landscap...
Presentation
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Opening keynote address, American Arachnological Society 2020 Virtual Summer Symposium. Video available at: https://youtu.be/zwsr2m7pt4A
Article
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The common ancestor of spiders likely used silk to line burrows or make simple webs, with specialized spinning organs and aerial webs originating with the evolution of the megadiverse "true spiders" (Araneomorphae). The base of the araneomorph tree also concentrates the greatest number of changes in respiratory structures, a character system whose...
Article
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Studies in evolutionary biology and biogeography increasingly rely on the estimation of dated phylogenetic trees using molecular clocks. In turn, the calibration of such clocks is critically dependent on external evidence (i.e. fossils) anchoring the ages of particular nodes to known absolute ages. In recent years, a plethora of new fossil spiders,...
Article
This study explores the web-building behavior of Gradungulidae for the first time, using the Otway odd-clawed spider Progradungula otwayensisMilledge, 1997. The web consists of a signal line leading to a retreat, an upper scaffold and a cribellate catching ladder connected to the substrate. The construction sequence and final structure of the catch...
Article
Genital traits are among the fastest to evolve, and the processes that drive their evolution are intensively studied. Spiders are characterized by complex genitalia, but the functional role of the different structures during genital coupling is largely unknown. Members of one of the largest spider groups, the retrolateral tibial apophysis (RTA) cla...
Article
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Spiders are known for producing specialized fibers. The radial orb-web, for example, contains tough silk used for the web frame and the capture spiral consists of elastic silk, able to stretch when prey impacts the web. In concert, silk proteins and web geometry affects the spider’s ability to capture prey. Both factors have received considerable r...
Article
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Spiders are a diverse group with a high eco-morphological diversity, which complicates anatomical descriptions especially with regard to its terminology. New terms are constantly proposed, and definitions and limits of anatomical concepts are regularly updated. Therefore, it is often challenging to find the correct terms, even for trained scientist...
Article
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Physical structures built by animals challenge our understanding of biological processes and inspire the development of smart materials and green architecture. It is thus indispensable to understand the drivers, constraints and dynamics that lead to the emergence and modification of building behaviour. Here, we demonstrate that spider web diversifi...
Article
The monotypic family Trogloraptoridae was only recently described from caves and old‐growth forest of Oregon and California (Western USA). These enigmatic spiders are characterized by striking raptorial claws, and based on their spinneret morphology, a close relationship to dysderoid spiders, a large clade within Synspermiata, was suggested. Here,...
Article
Several slowly evolving characters are evaluated with the main objective of reinforcing the higher classiication of Embioptera. An embiopteran femoral auditory organ, described here for the irst time, exhibits diferences in shape and position that provide diagnostic criteria for higher taxonomic groups in the order. New characters on silk ejectors,...
Article
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The new genus and species Myrmecicultor chihuahuensis Ramírez, Grismado, and Ubick is described and proposed as the type of the new family, Myrmecicultoridae Ramírez, Grismado, and Ubick. The species is ecribellate, with entelegyne genitalia, two tarsal claws, without claw tufts, and the males have a retrolateral palpal tibial apophysis. Some morph...
Article
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Web-building spiders are an extremely diverse predatory group due to their use of physiologically differentiated silk types in webs. Major shifts in silk functional properties are classically attributed to innovations in silk genes and protein expression. Here, we disentangle the effects of spinning behavior on silk performance of the earliest type...
Article
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The atypoid mygalomorphs include spiders from three described families that build a diverse array of entrance web constructs, including funnel-and-sheet webs, purse webs, trapdoors, turrets and silken collars. Molecular phylogenetic analyses have generally supported the monophyly of Atypoidea, but prior studies have not sampled all relevant taxa. H...
Article
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Filistatidae is one of the most phylogenetically enigmatic spider groups, and the genus Kukulcania Lehtinen includes the commonest representatives of the family. Its type species, K. hibernalis (Hentz, 1842), remains a favorite candidate for studies on spider phylogeny and comparative morphology. However, little is known about the taxonomy, species...
Presentation
Web-building spiders rely on their capture threads to retain prey. The threads of many species are therefore equipped with viscoelastic glue droplets. In contrast, cribellate spiders build a complex multi-fibre system endued with a wool of nanofibres. The processing of these cribellate capture threads is nearly unstudied, presumably due to the smal...
Presentation
Unpublished analysis of taxon delimitation provided by BOLD of Amaurobioidinae subfamily, in the context of "II Jornadas Argentinas de Aracnología".
Article
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The Convention on Biological Diversity (CBD) commits its 196 nation parties to conserve biological diversity, use its components sustainably, and share fairly and equitably the benefits from the utilization of genetic resources. The last of these objectives was further codified in the Convention's Nagoya Protocol (NP), which came into effect in 201...
Article
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While grasslands, one of Earth’s major biomes, are known for their close evolutionary ties with ungulate grazers, these habitats are also paramount to the origins and diversification of other animals. Within the primarily South American spider subfamily Amaurobioidinae (Anyphaenidae), several species are found living in the continent’s grasslands,...
Article
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Six new species of the genus Eutichurus Simon, 1897 are described: E. murgai new species (based on male and female) and E. paredesi new species (male) from Peru; E. cumbia new species (female) and E. tequendama new species (male) from Colombia; E. yungas new species (male and female) from Bolivia, and E. nancyae new species (male and female) from B...
Article
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Here we show that the most venomous spiders in the world are phylogenetically misplaced. Australian atracine spiders (family Hexathelidae), including the notorious Sydney funnel-web spider Atrax robustus, produce venom peptides that can kill people. Intriguingly, eastern Australian mouse spiders (family Actinopodidae) are also medically dangerous,...
Article
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The South American genus Diapontia is revised to include nine species: Diapontia uruguayensis Keyserling, 1877 (= Diapontia senescens Mello-Leitão, 1944 syn.n.; D. infausta Mello-Leitão, 1941 syn.n.; D. pourtaleensis Mello-Leitão, 1944 syn.n.; D. albopunctata Mello-Leitão, 1941 syn.n.) from northern Paraguay, southeastern Brazil, southern Uruguay,...
Article
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There is considerable controversy around the patterns and processes that influence spatial variation in taxonomic composition in mountain environments. We analysed elevational variation in the taxonomic composition of epigaeic spider assemblages across five mountains in north-western Patagonia (Argentina) to examine the relative importance of dispe...
Article
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Abstract. Filistatids represent an antique lineage of araneomorph spiders which are most diverse in arid and semiarid regions of the globe. Phylogenetic relationships among its genera are still largely unexplored, and previous studies disagree on the position of the North American Filistatinella Gertsch & Ivie, 1936, which could either be the siste...
Article
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The taxonomy of the poorly known South American goblin spider genus Birabenella Grismado (Araneae: Oonopidae) is updated in light of recently collected material. Three new species are described: B. kamanchaca, from northern Chile, B. portai, from northwestern Argentina, and B. chincha, from southern Peru, where the genus is reported for the first t...
Article
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Tityus curupi n. sp., belonging to the bolivianus complex, is described from the biogeographically distinct area of Paraje Tres Cerros in north-eastern Argentina. We also present a molecular species delimitation analysis between Tityus curupi n. sp. and its sister species Tityus uruguayensis Borelli 1901 to confirm species integrity. Furthermore, a...
Data
Table A. Chromosome measurements of postpachytene cells of Tityus curupi n. sp (2n = 32, 16II). Relative lengths expressed as percentage of total diploid complement length (%TCL). Mean values of N = 15 measured cells and their standard deviations (SD) are given. (*) indicate the rDNA bearing bivalent. Table B. Chromosome measurements of postpachyte...
Data
List of the studied material and Accession Numbers of the Coleccion Aracnológica of the Museo Argentino de Ciencias Naturales “Bernardino Rivadavia” (MACN-Ar) of the newly sequenced specimens used in the species delimitation analysis. (DOC)
Data
Table A. Accession Numbers for tissue samples from which DNA sequences were used in this study, deposited in the Colección Aracnológica of the Museo Argentino de Ciencias Naturales “Bernardino Rivadavia” (MACN-Ar), and GenBank accession codes for the D3 region of the 28S rDNA (28S-D3), 16S rDNA (16S) and Cytochrome c Oxidase Subunit I (COI) sequenc...
Article
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The tip of the legs concentrates the interactions that a spider has with the substrate where it lives. We review the morphology and evolution of spider feet, discussing the functional anatomy of their articulations and proposing a coherent terminology. All spiders consistently have two tendons to operate their feet and show a stereotyped sequence o...