Imperfect and askew: A review of asymmetric genitalia in araneomorph spiders (Araneae: Araneomorphae)

Bilateral asymmetry in the genitalia is a rare but widely dispersed phenomenon in the animal tree of life. In arthropods, occurrences vary greatly from one group to another and there seems to be no common explanation for all the independent origins. In spiders, genital asymmetry appears to be especially rare. Most known species show almost perfectly symmetrical genitals with the right and left sides being mirror images of each other. However, some examples of asymmetric genitalia have been studied and many other reports are scattered in the taxonomic literature. Based on a broad literature survey, we found several species in thirteen families with evidence of genital asymmetry, mostly expressed only in females. Our review suggests that spider genital asymmetries, although rare, are more common than previously thought and taxonomic descriptions and illustrations are a useful but not entirely reliable tool for studying them. Here we also report on directional asymmetry in the liocranid spider Teutamus politus, the first known case of morphologically asymmetric male genitals in Entelegynae spiders. Generalities, evolution and categorization of asymmetry in spiders are further discussed.Animal science

New leaf- and litter-dwelling species of the genus Pholcus from Southeast Asia (Araneae, Pholcidae)

We describe eight new species of the genus Pholcus, and document their microhabitats. Four species are assigned to the previously described Pholcus ethagala group: P. tanahrata Huber sp. nov., P. uludong Huber sp. nov., and P. bukittimah Huber sp. nov. from the Malay Peninsula, and P. barisan Huber sp. nov. from Sumatra. These species are all litter-dwellers that build domed sheet webs on the undersides of large dead leaves on the ground. The other four species are assigned to newly created species groups: the P. tambunan group with two species from northern Borneo: P. tambunan Huber sp. nov. and P. bario Huber sp. nov.; and the P. domingo group with two species from the Philippines, Mindanao: P. domingo Huber sp. nov. and P. matutum Huber sp. nov. These latter four species are leaf-dwellers that build barely visible silk platforms tightly attached to the undersides of live leaves. The main rationale for this paper is to provide part of the taxonomic and natural history background for upcoming phylogenetic and evolutionary (microhabitat shifts) analyses

Mining data from legacy taxonomic literature and application for sampling spiders of the Teutamus group (Araneae; Liocranidae) in Southeast Asia

Taxonomic literature contains information about virtually ever known species on Earth. In many cases, all that is known about a taxon is contained in this kind of literature, particularly for the most diverse and understudied groups. Taxonomic publications in the aggregate have documented a vast amount of specimen data. Among other things, these data constitute evidence of the existence of a particular taxon within a spatial and temporal context. When knowledge about a particular taxonomic group is rudimentary, investigators motivated to contribute new knowledge can use legacy records to guide them in their search for new specimens in the field. However, these legacy data are in the form of unstructured text, making it difficult to extract and analyze without a human interpreter. Here, we used a combination of semi-automatic tools to extract and categorize specimen data from taxonomic literature of one family of ground spiders (Liocranidae). We tested the application of these data on fieldwork optimization, using the relative abundance of adult specimens reported in literature as a proxy to find the best times and places for collecting the species (Teutamus politus) and its relatives (Teutamus group, TG) within Southeast Asia. Based on these analyses we decided to collect in three provinces in Thailand during the months of June and August. With our approach, we were able to collect more specimens of T. politus (188 specimens, 95 adults) than all the previous records in literature combined (102 specimens). Our approach was also effective for sampling other representatives of the TG, yielding at least one representative of every TG genus previously reported for Thailand. In total, our samples contributed 231 specimens (134 adults) to the 351 specimens previously reported in the literature for this country. Our results exemplify one application of mined literature data that allows investigators to more efficiently allocate effort and resources for the study of neglected, endangered, or interesting taxa and geographic areas. Furthermore, the integrative workflow demonstrated here shares specimen data with global online resources like Plazi and GBIF, meaning that others can freely reuse these data and contribute to them in the future. The contributions of the present study represent an increase of more than 35% on the taxonomic coverage of the TG in GBIF based on the number of species. Also, our extracted data represents 72% of the occurrences now available through GBIF for the TG and more than 85% of occurrences of T. politus. Taxonomic literature is a key source of undigitized biodiversity data for taxonomic groups that are underrepresented in the current biodiversity data sphere. Mobilizing these data is key to understanding and protecting some of the less well-known domains of biodiversity.Naturali

First records and three new species of the family Symphytognathidae (Arachnida, Araneae) from Thailand, and the circumscription of the genus Crassignatha Wunderlich, 1995

The family Symphytognathidae is reported from Thailand for the first time. Three new species: Anapistula choojaiae sp. nov., Crassignatha seeliam sp. nov., and Crassignatha seedam sp. nov. are described and illustrated. Distribution is expanded and additional morphological data are reported for Patu shiluensis Lin & Li, 2009. Specimens were collected in Thailand between July and August 2018. The newly described species were found in the north mountainous region of Chiang Mai, and Patu shiluensis was collected in the coastal region of Phuket. DNA sequences are provided for all the species here studied. The relations of these symphytognathid species were tested using previously published phylogenetic analyses on micro orb-weavers. Also, we used micro CT analysis to build 3D models of the male genitalia and somatic characters of two species of Crassignatha Wunderlich, 1995. The molecular phylogeny and 3D models were used to discuss the taxonomy and circumscription of the currently valid symphytognathid genera, with focus on Crassignatha and Patu Marples, 1951. Based on this, three new combinations are suggested: Crassignatha bicorniventris (Lin & Li, 2009), comb. nov., Crassignatha quadriventris (Lin & Li, 2009), comb. nov., and Crassignatha spinathoraxi (Lin & Li, 2009), comb. nov. A new record of Crassignatha danaugirangensis Miller et al. 2014 is reported from Brunei.Naturali