Meriola Banks
Creators: name: González, María E.
name: Grismado, Cristian J.
name: Ramírez, Martín J.
Publisher: name: Zenodo
Year: 2021
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Arachnida
Araneae
Trachelidae
Meriola

description: Genus Meriola Banks
Meriola Banks, 1895: 81 (type species by monotypy: M. decepta Banks, 1895); Platnick & Ewing, 1995: 8.
Diagnosis. Members of the genus Meriola resemble the American trachelids currently included in Trachelas and Trachelopachys by having male cuspules and reduced spination, but differ in several respects. The most remarkable characteristics are their almost straight, rather than recurved, posterior eye row (Fig. 1 a–b), narrower than in the other American genera (Fig. 1c), and the elongated, sharply tipped ventral leg cuspules (Fig. 4c).
Description. Small to medium sized trachelids (total length 2.52̅6.88). Carapace elongate to oval in dorsal view (Figs 1a, 2a, 3a), widest at rear of coxae II, cephalic and thoracic area shiny, with short thin hairs, or bearing tubercles associated with setal sockets (Figs 2 ̅3). Sockets may be on surface or in depressions on carapace (Figs 2c ̅d, 2f, 3c, 3f). In some cases, socket presents a cuticular fold on one side, resulting in a tubercle (Fig. 3e ̅f). These folds can vary in size, distribution and number in different species. Thoracic groove short. Color brownish-orange to dark brown, sometimes lighter posteriorly. Eyes: from above, anterior eye row slightly recurved to recurved, posterior eye row straight to slightly recurved; from front, anterior eye row slightly procurved, posterior eye row procurved (Fig. 10g ̅h); AME circular, dark, PME circular to oval, with silvery oblique tapeta forming a 90° angle between each other (Ramírez 2014: character 26), ALE and PLE circular to oval, silvery; eyes nearly equal in size, except some species where AME are slightly smaller; all eyes about evenly spaced; MOQ-AW ± MOQ-PW (Fig. 1a). Clypeal height about equal to AME diameter. Chelicerae with three teeth on promargin and two on retromargin. Endites rectangular, their inner margins with distinct longitudinal depression, distal portion of their external edge angulate, parallel; labium nearly trapezoidal, almost as long as its basal width, in general with basal protuberances and constriction near base; sternum oval to heart-shaped, longer than wide, pointed behind coxae IV. Palpal claw without teeth. Precoxal triangles present in both sexes. Legs: spination reduced (see under species description), species-specific except for females of M. balcarce Platnick & Ewing and M. foraminosa Keyserling, both with distal spine on prolateral side of femur I; metatarsi III and IV sometimes with preening combs (Fig. 4g). Macrosetae present as cuspules in some males, but absent females and males of M. californica, M. decepta, M. foraminosa, M. lineolata comb. nov., M. mauryi Platnick & Ewing, M. ramirezi and M. tablas Platnick & Ewing; present in M. macrocephala (Nicolet) comb. nov. females. Cuspules elongated and sharply tipped, on ventral side of tibiae, metatarsi and tarsi, number varying intra- and interspecifically (Fig. 4c; compare Figs 56g ̅h with 57h̅i). Leg segments pale brown to yellowish-brown, in some cases with dark rings, or tibiae I darker. Scopulae composed of distally spatulate tenent setae, from distal end of metatarsi to distal tarsi I and II (Figs 4a, 4c), absent on III and IV. Females of some species exhibit strong ventral scopula on anterior legs, which start as loosely dense in distal tibiae and become stronger towards tarsus. Claw tufts composed of spatulate setae, with block-like shape of the bases (Ramírez 2014: figs 72A̅C). The mesal side of the seta, at its insertion, is widely expanded in large blocks with defined vertices, while the ectal side becomes narrow (Figs 4e, h). Claws pectinate, claw-tuft clasping mechanism present in structure of teeth appressed together, with claw lever file-claw tuft bases interlocking (observed with SEM in M. penai Platnick & Ewing, M. mauryi, M. fasciata Mello-Leit „o and M. macrocephala) (Figs 4b, h; Ramírez 2014: figs 72A̅C). Tarsal organ capsulate, aperture oval to slit-shaped (Ramírez 2014: fig. 58O). Trichobothria with transversal ridges on anterior hood, shaft with basal bulbous expansion with bumps (Fig. 4d, Ramírez 2014: fig. 96D). Abdomen of male sometimes with dorsal faintly slightly sclerotized area, on anterior half (Fig. 35a), posterior half (Figs 62a, 74a), or most of dorsum (Fig. 71a); without epiandrous spigots. Coloration: dorsum grayish-brown or brownish, sometimes with chevrons, reticulations and/or cardiac mark; venter pale, in cases with dark ventral stripe, epigastric area of males more sclerotized. Tracheal spiracle about ALS length, just before spinnerets. Spinnerets (Fig. 6; observed with SEM in M. rahue Platnick & Ewing, M. fasciata, M. macrocephala): Anterior lateral spinnerets with single major ampullate gland spigot and several piriform gland spigots (Figs 6b, f, j). Posterior median spinnerets of females with five large cylindrical gland spigots, as well as single minor ampullate gland spigot and few aciniform gland spigots (Fig. 6c; Ramírez 2014: fig. 133G); males with single minor ampullate gland spigot and few aciniform gland spigots (Figs 6g, k). The posterior lateral spinnerets bear two cylindrical gland spigots in females and several aciniform gland spigots in both sexes (Figs 6d, h, i; Ramírez 2014: fig. 114D). Genitalia: Male palp with retrolateral tibial apophysis (Fig. 5f); copulatory bulb with simple looping sperm duct, median apophysis absent, embolus long and slender to short and thick (Figs 5e, 21b, 63c). Epigyne with median field of variable size, lateral lobes in general with sclerotized ridges (Fig. 5a), primary spermatheca usually small, identified by origin of fertilization duct, which is close to epigastric furrow, secondary spermathecae present, sometimes larger than primary spermatheca, identified by gland ducts, with additional expansion of copulatory duct, here referred to as copulatory duct receptacle (CDR) (Figs 5b, c; 24b).
Distribution. All species occur in temperate to subtropical areas of the New World, with most of the diversity in southern South America (Peru, Bolivia, Brazil, Chile and Argentina). There are two native species in North America, one (M. californica) occurring only on the west coast, while the second (M. decepta) is found throughout most of U.S.A. and southeast Canada. In addition, an introduced species native to South America (M. arcifera) occurs in California. There are as well isolated records of M. foraminosa in Venezuela and Ecuador, which may be the result of poor collecting efforts, and of M. decepta in Guatemala, Colombia, Peru and Brazil, probably due to anthropogenic introductions.
description: Published as part of González, María E., Grismado, Cristian J. & Ramírez, Martín J., 2021, A Taxonomic Revision Of The Spider Genus Meriola Banks (Araneae: Trachelidae), pp. 1-113 in Zootaxa 4936 (1) on pages 6-12, DOI: 10.11646/zootaxa.4936.1.1, http://zenodo.org/record/4559165