Tylorida Simon 1894
Creators: name: Sankaran, Pradeep M.
name: Malamel, Jobi J.
name: Joseph, Mathew M.
name: Sebastian, Pothalil A.
Publisher: name: Zenodo
Year: 2017
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Arachnida
Araneae
Tetragnathidae
Tylorida

description: Tylorida Simon, 1894
Type species: Tylorida striata (Thorell, 1877), originally described as Meta striata Thorell, 1877.
Rediagnosis. Genus Tylorida can be separated from other described tetragnathid genera by the following combination of characters: femora IV with smooth trichobothrial shaft, cymbial dorso-basal process shorter than half the cymbial width and perpendicular to the cymbium longitudinal axis, short, acute embolus with a broad, twisted embolic base, short, lamelliform conductor lying dorsal to embolus, ventrally swollen tegulum with a distomedian triangular process, long, tubular fertilization ducts connected to both copulatory ducts and spermathecal bulb, copulatory and fertilization ducts running parallel before entering into spermathecal bulb (Álvarez-Padilla & Hormiga 2011: figs 115F, 116C, 117A, B, F; present data: Figs 4H, 8A–H, 10A–H, 11B, D, E–F, 14A–D, F, 17A– D, F–I, K–N, 18 C, F, I, L, O).
Relationship. Genus Tylorida is closely allied to the genus Orsinome (Álvarez-Padilla et al. 2009; Álvarez- Padilla & Hormiga 2011; Dimitrov & Hormiga 2011). Members of both these genera are similar in size, colouration (compare Figs 5A–F, 6A–D, 15A–F with 20A–F) and web building behaviour (Álvarez-Padilla & Hormiga 2011: fig. 5C, E), making them misplaced within both the genera. Females of both genera share similar cheliceral dentition: three promarginal and four retromarginal teeth (compare Fig. 12B, D, G, I with K). Male chelicerae of Orsinome spp., however, significantly differ from that of Tylorida spp. In the former, the male chelicerae are massive, nearly as wide as long with cheliceral apophysis and less number of teeth, while in the latter, it is longer than wide with numerous teeth and without any apophysis (compare Fig. 12A, C, F, H with J and Álvarez-Padilla & Hormiga 2011: fig. 101D, H).
Members of both the genera differ significantly in male and female genitalia. Whereas in Tylorida spp., the pedipalp possesses a short embolus, short, lamelliform conductor, that clearly separated from embolus, distomedian triangular process of tegulum and basally placed cymbial dorso-basal process, the pedipalp of Orsinome spp. share features such as long embolus, long conductor, which appears contiguous to embolus, tegulum without disto-median triangular process and a more or less distally placed cymbial dorso-basal process (compare Figs 10A– I, 14A–D, 17A–D, F–I, K–N, with 21A–E, Álvarez-Padilla & Hormiga 2011: fig. 103A, F). In contrast to the epigyna of Tylorida spp., which have prominent epigynal plate, widely separated copulatory openings and very long, tubular fertilization ducts, the epigyna of Orsinome spp. are characterised by less prominent epigynal plate, short, thick fertilization ducts and having closely placed/contiguous copulatory openings placed in a common chamber (genital opening) at the centre of the epigynal plate (compare Figs 11A–F, 14E–F, 18A–O with Fig. 21F– G, Zhu et al. 2003: fig. 164D, E, Álvarez-Padilla & Hormiga 2011: figs 102A, 104E).
Taxonomic significance of male chelicerae of Tylorida. Most tetragnathid males are characterised by conspicuously enlarged chelicerae, often armoured with numerous teeth and specialized cheliceral apophyses, which are used for cheliceral clasp during courtship and mating (Bristowe 1958; Eberhard & Huber 1998). Like members of the genus Tetragnatha Latreille, 1804, whose chelicerae are taxonomically significant in systematics, the chelicerae of male Tylorida spp. are useful in species identification and in the case of Tylorida, it is particularly significant as the members are extremely similar to each other in both male (Figs 8A–H, 14A–D, 17A–D, F–I, K– N) and female (Figs 9A–D, 14E–F, 18A–O, Jäger & Praxaysombath 2009: fig. 25) genitalic aspects and exhibiting intense intraspecific variations, both somatic as well as genitalic (Figs 1E–F, 5A–F, 6A–D, 8A–H, 9A–D, 10A–H, 11A–F, 12A–D, 16A–J, 17A–D, F–I, K–N, 18A–O, Jäger & Praxaysombath 2009: figs 24, 28–31, 33, 36–37), which will make species identification hard. We have examined 4 male specimens of T. marmorea, 1 male specimen of T. striata and twenty one male specimens of T. ventralis. Despite the small sample size, it was found that the male chelicerae of all the Indian Tylorida spp. lack specialized apophysis/apophyses, but possess teeth and tubercles that are varying in number, shape, size and mutual spacing from species to species (Figs 12A, F, H). Unlike males, females have chelicerae armed with similar number of teeth: three promarginal teeth, which are slightly larger than the four retromarginal teeth (Figs 4D, 12B, G, I).
description: Published as part of Sankaran, Pradeep M., Malamel, Jobi J., Joseph, Mathew M. & Sebastian, Pothalil A., 2017, On the genus Tylorida Simon, 1894 with the first record of the genus Atelidea Simon, 1895 from India (Araneae: Tetragnathidae, Leucauginae), pp. 294-326 in Zootaxa 4353 (2) on pages 295-296, DOI: 10.11646/zootaxa.4353.2.3, http://zenodo.org/record/1065166