Plato Coddington, 1986

Prete, Pedro H. & Brescovit, Antonio D., 2024, Taxonomic revision of the orb weaving spider genus Plato Coddington, 1986 (Araneae: Theridiosomatidae) with the description of three new species, Zootaxa 5471 (1), pp. 1-32 : 3

Plato Coddington, 1986

Plato Coddington, 1986: 28 ,

type species by original designation: Plato troglodita Coddington, 1986: 29 .

Diagnosis. Plato species are identified by the following combination of characters: males with a general palp conformation similar to those of Chthonos , but Plato has a large and sclerotized apophysis in the conductor (figs. 3B; 5B; 7F; 9C, D, E, F; 11B; 14B; 16C, D, E; 19B, C; 22C), at least two times the length of the apophysis in Chthonos ( Coddington 1986, fig. 30), mesal or distal notch on the cymbium (figs. 19E, 22C), absent in Chthonos , very sharp and pointed cymbium (fig.7B) and cymbial lamella (fig. 1C; 9H; 11F; 14E; 16H; 19G), also absent in Chthonos . The females have a dorsal plate in the epigynum forming an atrium (figs. 4E; 6C, D, E, F; 8D; 10C, D; 12E; 15E; 17C, D; 20C, E, G; 21C, E, G). Strong spines in legs I and II, sclerotized punctuations on abdominal projections and ventrally expanded sternum are absent in Plato , unlike Chthonos .

Description. See Coddington, 1986: 28–29. Additional information: lower cephalic region (except Plato striatus ). Clypeus with 2 or 3 times the diameter of the AME. Diameter ALE and PLE are the same. Distance PME 1x the diameter of the PMEs (fig. 8A). Legs may be darker near the joints in some species (figs. 4A; 5A; 7A; 8A; 18A; 21A; 22A, B), with tarsus and metatarsus being shorter than tibia, patella, and femur (I, II, III and IV). Male palp: internal cymbial lamella, visible only with expansion (figs. 1C; 9H; 11F; 14E; 16H; 19G). Paracymbium Tshaped with a tapered side (figs. 1C; 9H; 11F; 14E; 16H; 19G). Median apophysis with curve and sclerotized tip (fig. 1A, B) situated in the basal area of palp, next to palpal tibia (fig. 3C, 7B). Conductor hyaline, partially covering the embolus (figs. 1A, B; 5B, C, F; 7B, C, D, F), with a thick apophysis, which may or may not be bifid. Embolus flattened with median opening, which can be single, bifid, or tripartite, forming the embolic apophysis shortly after the opening, visible only in an expanded palp (figs. 5C, F; 7C, D, F; 9F, G) and often joined to the embolus by a hyaline membrane. The embolic apophysis emerges is anteriorly to the embolus (fig. 9G), and it length is variable and may be shorter, equal, or longer than the embolus (figs. 5C; 7C, D; 9F, G; 11D, G; 14A, D; 16F, G; 18E). Epigynum: epigynal plate is wider than longer, sclerotized transversal groove (figs. 2A, C; 4B) with or without abrupt median projection (figs. 2B, C; 4B, F; 6B, D; 8B; 15B–F; 21D), where there is a support (Su) for fitting the palp sclerites. Internally, it has a sclerotized dorsal plate (DP), where it is fused (fig. 15E) or partially fused (figs. 2E; 17D) in the posterior part of the ventral epigynal plate, near the end of the transversal groove (TG). The dorsal plate forms an atrium (figs 2E; 17D) which may or may not wrap the spermathecae. Hyaline copulatory ducts with simple inverted “U” shaped route (figs. 4C; 6C; 8C; 10C; 13C). The spermathecae connate has laterally inserted fertilization ducts (figs. 4C, 6E).

Figs. 1 and 2 clarify and standardize the terminology of genital structures of Plato through color differentiation and abbreviations.

Species composition. Plato troglodita Coddington, 1986 , P. bicolor ( Keyserling, 1886) , P. bruneti ( Gertsch, 1960) , P. ferriferus Prete, Cizaukas & Brescovit, 2018 , P. guacharo ( Brignoli, 1972) , P. juberthiei Lopez, 1996 , P. miranda ( Brignoli, 1972) , P. novalima Prete, Cizaukas & Brescovit, 2018 , P. striatus Prete, Cizauskas & Brescovit, 2018 , P. omnipraesens n. sp. Prete & Brescovit, 2022, P. hamatus n. sp. Prete & Brescovit, 2022 and P. peruana n. sp. Prete & Brescovit, 2022.

Figures

FIGURE 1. Palp of Plato. A, B, Plato bicolor from Cave Maroaga, Presidente Figueiredo, Amazonas, Brazil, SEM; C, Plato ferriferus from Parauapebas, Pará, Brazil, SEM; A, mesal view; B, ventral view, expanded; C, cymbium, ventral view. Structures are marked with different colors.Abbreviations, AL, alveolus. C, conductor. CA, conductor apophysis. CL, cymbial lamella. Cy, cymbium. E, embolus. EA, embolic apophysis. MA, median apophysis. O, embolic opening. PC, paracymbium. ST, subtegulum. T, tegulum. Scales: A–C, 0.2.

FIGURE 2. Epigynum of Plato omnipraesens n. sp., from Parque Estadual da Terra Ronca, São Domingos, Goiás, Brazil. A, ventral view, SEM; B, posterior view, SEM; C, dorsal view, illustration; D, lateral view, SEM; E, lateral cut view. Structures are marked with different colors. Abbreviations, At, atrium. CD, copulatory ducts. CP, central pit. DP, dorsal plate. FD, fertilization ducts. S, spermathecae. Su, epigynal support. TG, transversal groove. Scales: A–E, 0.2.