The poorly known mygalomorph genus Thalerommata Ausserer, 1875 is redescribed and rediagnosed. Thalerommata gracilis Ausserer, 1875 (type species) and T. macella (Simon, 1903) are rediagnosed. Thalerommata meridana (Chamberlin & Ivie, 1938) is considered a nomen dubium. Six new species are described: T. squamea n. sp., T. huila n. sp., T. splendens n. sp., T. pecki n. sp., T. maculata n. sp., and T. gertschi n. sp. Thalerommata is transferred from Barychelidae to Theraphosidae and considered closely related with Trichopelma Simon, 1888, with which it shares the biserially dentate superior tarsal claws in males in combination with non-incrassate PLS. The genus is distributed from northern South- America to the Caribbean.

Seven new species of Schismatothele Karsch, 1879 (Araneae, Theraphosidae) are described, almost doubling the diversity of the genus: S. caeri sp. nov.; S. caiquetia sp. nov.; S. merida sp. nov.; S. moonenorum sp. nov.; S. quimbaya sp. nov.; S. timotocuica sp. nov. and S. wayana sp. nov. An identification key for all species of Schismatothele (except S. kastoni) is presented, as well as a complementary diagnosis for the genus. Also, a standardized nomenclature is proposed to describe the prolateral keels of male palpal bulbs of species of Schismatothele.

Nhandu sylviae sp. nov. is described from Guyana, representing the first record of the genus Nhandu Lucas, 1983 from Guyana and the first record in northern South America.

The female of Melloina gracilis (Schenkel, 1953), a species previously known only from males, is described. This is the second species of the genus known from both sexes. Detailed morphological description and figures of the female specimen are presented. A reanalysis of Mori & Bertani, 2020 matrix is done and some comments about the familial placement of the genus Melloina Brignoli, 1985 are made.

Paraje Tres Cerros is a low altitude hilly natural area surrounded by cattle fields and characterized by three isolated rocky formations of about 150–180 m a.s.l. located in the Corrientes province of Argentina. Their topographic and environmental conditions are unique across the whole Mesopotamian littoral of Argentina and, therefore, can be considered as a biogeographic island that hosts several endemic species of plants and animals. The lack of knowledge of the mygalomorph spider species of the area led us to conduct a field study at Paraje Tres Cerros with the objective of surveying these spiders. From this survey, we described two new endemic species, Stenoterommata isa sp. nov. (Pycnothelidae) and Catumiri sapucai sp. nov. (Theraphosidae); and we recorded Xenonemesia platensis for the first time in the Corrientes province. In addition, we described the sexual behavior of Stenoterommata isa sp. nov. and Catumiri sapucai sp. nov. for the first time. We presented distribution maps for the Argentinean species of Stenoterommata, for the genus Catumiri as well as for Xenonemesia platensis. Stenoterommata isa sp. nov. constitutes the eighth known species of the genus in Argentina and according to its distribution is the only exclusive species recorded in the Corrientes province. Regarding its sexual behavior, we obtained one mating, which consisted in touches the female legs with legs I and II by the male, who starts the courtship by beating the female’s cephalothorax and sternum with legs II and palps respectively. Then the male clasps with the first pair of legs between the palp base and chelicerae of the female and elevate her to reach the genital opening for the palpal insertions. Catumiri sapucai sp. nov. is the third species described from Argentina with a new spermathecae shape with two additional elongated digitiform domes external to the inner receptacles. We obtained five matings for this species, two of which involved males contacting females without an evident courtship. For the remaining three, the males initiated courtship by performing a few quick body vibrations. All males achieved the typical copulation position observed in most mygalomorphs and made about 3 to 5 palpal insertions, with the exception of one case in which spiders lost equilibrium and separated from each other. The presence of Xenonemesia platensis at this area is based on one adult female, thus further campaigns to collect more specimens will lead us to confirm this record or to better elucidate its taxonomic identity.

Chinchaysuyu gen. nov. is described as a new monotypic Theraphosidae genus from northern Peru, with distinct genitalic morphology. Males of Chinchaysuyu gen. nov. differ from all known species by having a palpal bulb organ with many conspicuous keels extending towards the subtegulum. Females differ by having two pairs of short and hyper-sclerotized receptacles. This new genus is described and illustrated on the basis of the type species Chinchaysuyu spinosa sp. nov. and their morphological affinities and its phylogenetic position are analyzed and discussed.

The taxonomic status of some Mexican and Central American species within the genus Aphonopelma Pocock, 1901 are reviewed primarily based on the morphology of the male palpal bulb in preparation for more comprehensive treatments of these species in future works. Aphonopelma latens (Chamberlin, 1917) is regarded as a junior synonym of Aphonopelma seemanni, (F. O. Pickard-Cambridge, 1897) syn. nov. based on palpal bulb, tibial apophysis, metatarsal apophysis morphology and biogeography. Dugesiella Pocock, 1901 is removed from synonymy with Aphonopelma with the genotype restored to its original combination Dugesiella crinita Pocock, 1901 gen. et comb. rest. Aphonopelma duplex (Chamberlin, 1925), Aphonopelma serratum (Simon, 1891) and Aphonopelma anitahoffmannae Locht et al., 2005 are transferred to the genus Dugesiella based primarily on palpal bulb morphology and geographical distribution creating the restored combination Dugesiella duplex comb. rest., and the new combinations Dugesiella serrata comb. nov. and Dugesiella anitahoffmannae comb. nov.

Background The theraphosid spider genus Chilobrachys Karsch, 1892 contains 30 species, almost entirely limited to Indochina, India, Sri Lanka and China. Six species of Chilobrachys are currently known from China: C. dominus Lin & Li, 2022 (Yunnan), C. guangxiensis (Yin & Tan, 2000) (Guangxi, Hainan), C. hubei Song & Zhao, 1988 (Hubei, Chongqing), C. jinchengi Lin & Li, 2022 (Tibet), C. liboensis Zhu & Zhang, 2008 (Guizhou, Guangxi) and C. lubricus Yu et al., 2021 (Yunnan). New information A new species, Chilobrachys qishuoi Lin & Li, sp. n., is described from Guangdong, China, on the basis of both sexes. This is the easternmost Chilobrachys species known. Photos and a morphological description of the new species are provided. Type materials are deposited in the Institute of Zoology, Chinese Academy of Sciences (IZCAS) in Beijing, China.

The species Pamphobeteus antinous Pocock, 1903, P. fortis (Ausserer, 1875), P. insignis Pocock, 1903, and P. ornatus Pocock, 1903 are redescribed, based on examination of the respective type material. Lectotypes are designated for Pamphobeteus ferox (Ausserer, 1875) and P. nigricolor (Ausserer, 1875), with these taxa also redescribed. A new diagnosis and description of Pamphobeteus augusti (Simon, 1889) is presented, based on a non-type male compared against illustrations of one of the syntypes. New distribution records of Pamphobeteus grandis Bertani, Fukushima & Silva, 2008 are presented from Peru. Four new species of Pamphobeteus Pocock, 1901 are described: P. nellieblyae sp. nov., P. urvinae sp. nov. and P. zaruma sp. nov. from Ecuador, and P. lapola sp. nov. from Colombia.

Theraphosidae is the most diversified family of mygalomorph spiders, commonly known as tarantulas. Two genera inhabit the Mediterranean region: Chaetopelma in the east and Ischnocolus mostly in the western part of the Basin. Their phylogenetic position and the validity of some Ischnocolus species remain unclear. We implemented a multilocus target approach to shed new light on the position of both genera and further integrated molecular data with additional lines of evidence (morphology and ecology) to explore species boundaries in western Mediterranean Ischnocolus. Our results reveal that Ischnocolus and Chaetopelma are not closely related. Chaetopelma formed a clade with the African subfamily Eumenophorinae and Ischnocolus was recovered in a clade comprising all remaining theraphosids. The western Mediterranean Ischnocolus comprises two deeply divergent clades that separated during the Early Miocene and differ in both morphology and lifestyle. We found molecular, morphological and ecological evidence to restore the name Ischnocolus mogadorensis and revalidate this species. We also uncovered distinct allopatric lineages in Ischnocolus elongatus. However, the lack of males, the uniform morphology of females and low withinclade support hampered the assessment of their status and boundaries. Finally, our data support that I. elongatus should be considered a senior synonym of Ischnocolus hancocki and Harpactirella insidiosa.