BACKGROUND: Literature on systemic envenomation caused by tarantula bites, particularly from the Theraphosidae family, is relatively scarce. This case report provides a formal description of the first known instance of systemic envenomation caused by the Socotra Island Blue Baboon Tarantula (Monocentropus balfouri).
METHODS: In this case, a 23-year-old employee of an exotic pet shop suffered from perioral paresthesia, generalized muscle cramps, and rhabdomyolysis because of a Monocentropus balfouri bite. His symptoms were successfully relieved with oral benzodiazepines. EMERGENCY PHYSICIAN BE AWARE OF THIS?: This case highlights the potential for serious complications resulting from the bite of Monocentropus balfouri, a species gaining popularity among global exotic pet collectors.

The extreme asymmetry of species richness distribution across the tree of life has always intrigued evolutionary biologists. Two competing explanations have been proposed to explain this pattern-the clade age hypothesis and diversification rate variation. While these two scenarios may not be mutually exclusive, to what extent time and diversification rates interact to explain species richness patterns remains understudied. Here, we investigate the relative influence of these two scenarios using tarantulas (Family: Theraphosidae) as a model. Tarantulas represent a speciose group of spiders found worldwide but exceptionally diverse in South America. These spiders show two distinct patterns of microhabitat use (ground-dwelling or arboreal) and defense strategies (presence or absence of urticating hairs). Using various trait-independent and dependent diversification models, we test the clade age hypothesis, the role of microhabitat, antipredator defense strategy, and geography in influencing diversification rates. Our results suggest that clade age is the primary predictor of species richness distribution across the tarantula subfamilies. However, the presence of urticating hair probably disrupted this pattern in some clades by increasing the net diversification rates, not by increasing the speciation rate but by reducing the extinction rate.

Three new species of Cymbiapophysa Gabriel & Sherwood, 2020 are described from south, central, and north-western Ecuador, showing the wide range of distribution that this genus has in Ecuador and its biogeographical provinces. These three new species are easily differentiated from other congeners based on keel morphology of the male palpal bulb. Supplementary information about the locality of C.magna Sherwood, Gabriel, Brescovit & Lucas, 2021 is provided, alongside additional data on morphology and some commentaries about the general distribution and biogeography of Cymbiapophysa. Additionally, a taxonomic key for males of Cymbiapophysa species is presented, based on the palpal bulb morphology.

Tarantula envenomations are encountered infrequently but may increase with increased exotic animal ownership. This case report presents the first documented toxicity from a Venezuelan suntiger tarantula (VST), Psalmopoeus irminia, and provides a general framework for approaching patients with tarantula exposures.
A 35-year-old man presented to an emergency department 4 h after experiencing a bite from his pet VST. He developed erythema, pain, and edema to the bite site on the left thenar eminence that extended proximally. Within 4 h, he developed abdominal pain, nausea, vomiting, throat itching, and tightness. The patient had a blood pressure of 131/105 mm Hg, heart rate of 102 beats/min, 36.6°C, respiratory rate of 20 breaths/min, and SpO2 of 94%. Laboratory evaluations were within normal limits (other than chronically elevated but improved transaminases). The patient received 0.5 mg epinephrine intramuscularly, 50 mg diphenhydramine IV, 20 mg famotidine IV, 0.4 mg ondansetron IV, and 1 L of normal saline for a suspected anaphylactic reaction. Shortly after epinephrine administration, his gastrointestinal and upper airway symptoms resolved. All symptoms resolved within 1 week. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: Little is known about VST toxicity. Therefore, providers should rely on a general framework for approaching patients with tarantula exposures. Morbidity from tarantula exposures is mediated by mechanical injury, venom effects, and hypersensitivity reactions. Typical clinical findings include local pain, pruritis, edema, erythema, and burning. Muscle cramping, ophthalmia nodosa, and hypersensitivity reactions may occur. Treatment is primarily supportive and includes decontamination, cool compresses, analgesia, treatment of anaphylaxis, and ophthalmology evaluation if ocular exposure.

Spiders represent an evolutionary successful group of chelicerate arthropods. The body of spiders is subdivided into two regions (tagmata). The anterior tagma, the prosoma, bears the head appendages and four pairs of walking legs. The segments of the posterior tagma, the opisthosoma, either lost their appendages during the course of evolution or their appendages were substantially modified to fulfill new tasks such as reproduction, gas exchange, and silk production. Previous work has shown that the homeotic Hox genes are involved in shaping the posterior appendages of spiders. In this paper, we investigate the expression of the posterior Hox genes in a tarantula that possesses some key differences of posterior appendages compared to true spiders, such as the lack of the anterior pair of spinnerets and a second set of book lungs instead of trachea. Based on the observed differences in posterior Hox gene expression in true spiders and tarantulas, we argue that subtle changes in the Hox gene expression of the Hox genes abdA and AbdB are possibly responsible for at least some of the morphological differences seen in true spiders versus tarantulas.

The Colombian Pacific coast is an amazing natural region, immersed in one of the most unknown biodiversity hotspots in the world. An expedition carried out in the north of this area, at the Jardín Botánico del Pacífico (JBP) in Bahía Solano, Chocó, focused on studying the diversity of the mygalomorph spider fauna, allowed us to discover four new species included in the families Halonoproctidae and Theraphosidae. The trapdoor species Ummidiasolanasp. nov., and the theraphosids species Euthycaeluscunampiasp. nov. (Schismatothelinae), Melloinapacificasp. nov. (Glabropelmatinae), and Neischnocolusmecanasp. nov. (Theraphosinae) are illustrated, diagnosed, and described in detail. Photographs of somatic features and copulatory organs and a distribution map are provided. Morphological, taxonomical, and biogeographical aspects are discussed for each species. All these taxonomic novelties represent the first records of these genera for the region, expanding the range of geographic distribution of each of them. This work constitutes the first effort focused on characterizing the community of Mygalomorphae species in the Chocó Biogeographic Region.

Taxonomic researchers have used multiple sources of evidence to support species hypotheses and delimitations. Grammostola Simon (Mygalomorphae: Theraphosidae) comprises 20 valid species endemic to South America, six occurring in Brazil. The classical morphological approach based mainly on genitalia may be misleading in recognizing species in this genus. Thus, we used morphology, geographical distribution, genetic distance, and phylogeny to support the redescription of Grammostola pulchra from southern Brazil, a species described a century ago. We also diagnosed and illustrated the species. Males have a developed apical keel at the apex of the embolus; for the first time, this type of structure has been reported in a species of Grammostola. The molecular analyses using the partial sequence of Cytochrome c oxidase subunit I showed 7% of genetic distance (p-distance) between G. pulchra and Grammostola anthracina. Distance and tree-based methods (ASAP and bPTP, respectively) assigned G. pulchra as a valid species. The gene-tree under Bayesian and Maximum-Likelihood recovered a similar topology, placing G. pulchra as closely related to Grammostola burzaquensis and G. anthracina. Morphological characters which could be important in the taxonomy of the genus are further discussed.

Invertebrates, including arachnids, are a common taxon in zoological collections. Invertebrate medicine and pathology are emerging subspecialties, but there is limited reference material or published resources describing histologic lesions in arachnids. Histopathology of 26 captive arachnids (20 spiders and 6 scorpions) from institutional collections was reviewed. Most animals were found dead with limited clinical signs. Tissues evaluated included body wall (cuticle and epidermis), skeletal muscle, book lungs, digestive tract (pharynx, esophagus, sucking stomach, midgut tube, midgut diverticula, and stercoral pocket), central and peripheral nervous system, heart, hemolymph vessels and sinuses, Malpighian tubules, coxal glands, and gonads. Inflammation was frequent (24/26, 92%), and seen in multiple organs (18/24, 75%) with the midgut diverticulum most commonly affected (14/24, 58%) followed by the book lungs (13/24 arachnids, 54%), and body wall (8/24 arachnids, 33%). Inflammation comprised hemocyte accumulation, hemocytic coagula, melanization, and nodulation. Infectious agents, including bacteria (11/26, 42%), fungi (10/26, 38%), and parasites (2/26, 8%), were seen within inflammatory aggregates. Coinfection with multiple infectious agents was common (6/24, 25%). No etiologic agent was identified in 7/24 (29%) cases with inflammatory lesions. Lesions suggestive of decreased nutritional status or increased metabolic rate included midgut diverticula atrophy in 11/26 (42%) animals and skeletal muscle atrophy in 6/26 (23%) animals. Atrophic lesions were seen in combination with infection (8/11, 73%), pregnancy (2/11, 18%), male sex (2/11, 18%), or without other lesions (1/11, 9%). Other suspected contributors to death included dysecdysis-associated trauma (2/26, 8%) and uterine intussusception (1/26, 4%). No animals had neoplasia.

Tarantulas are commonly kept as pets and bites from some species can cause severe symptoms. Here we describe a case of a patient with transient atrial fibrillation (afib) and painful muscle cramps requiring hospitalization for pain management after being bitten by a Poecilotheria tigrinawesseli (Wessel\'s Tiger Ornamental) spider. He was discharged with a cardiac event monitor and outpatient cardiology follow-up. The event monitor documented transient afib which decreased in frequency then resolved halfway through the three-week monitoring period. In conclusion, tarantula envenomation is usually mild with local pain and edema most reported. However, bites by some species, such as P. tigrinawesseli may have local and more systemic, long-lasting effects.

Spider venoms constitute a trove of novel peptides with biotechnological interest. Paucity of next-generation-sequencing (NGS) data generation has led to a description of less than 1% of these peptides. Increasing evidence supports the underestimation of the assembled genes a single transcriptome assembler can predict. Here, the transcriptome of the venom gland of the spider Pamphobeteus verdolaga was re-assembled, using three free access algorithms, Trinity, SOAPdenovo-Trans, and SPAdes, to obtain a more complete annotation. Assembler\'s performance was evaluated by contig number, N50, read representation on the assembly, and BUSCO\'s terms retrieval against the arthropod dataset. Out of all the assembled sequences with all software, 39.26% were common between the three assemblers, and 27.88% were uniquely assembled by Trinity, while 27.65% were uniquely assembled by SPAdes. The non-redundant merging of all three assemblies\' output permitted the annotation of 9232 sequences, which was 23% more when compared to each software and 28% more when compared to the previous P. verdolaga annotation; moreover, the description of 65 novel theraphotoxins was possible. In the generation of data for non-model organisms, as well as in the search for novel peptides with biotechnological interest, it is highly recommended to employ at least two different transcriptome assemblers.