Mecynogea infelix
Creators: name: Martins, Pedro H.
name: Santos, Adalberto J.
Publisher: name: Zenodo
Year: 2018
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Arachnida
Araneae
Araneidae
Mecynogea
Mecynogea infelix

description: Mecynogea infelix (Soares & Camargo, 1948) revalidated
Figs 1–8
Wixia infelix Soares & Camargo, 1948: 378, fig. 35 (female holotype from left side of Rio das Mortes, Xavantina, Mato Grosso, Brazil, [18°14'58"S, 43°36'1"W], 6.II.1947, H. Sick leg., deposited in MZSP 1300, examined). Brignoli 1983: 281. Mecynogea infelix — Levi 1993: 56
Mecynogea bigibba Simon, 1903 — Levi 1997: 222 –224 (Syn).
Mecynogea chavona Levi, 1997: 230, figs 65–66, map 2D (Male holotype from Finca Chenevo, 20 km N Río Muco, 20 km S El Porvenir, ca. 170 m, Depto. Meta, Colombia, [4°25'18.97"S, 72°0'53.93"W], 1979, W. Eberhard leg., deposited in MCZ 20767, examined by photograph). New synonymy.
Mecynogea bigibba Simon, 1903 — Levi 1997: 222 –224, figs 10–14 (in part, some females).
Mecynogea lemniscata (Walckenaer, 1849) — Levi 1997: 227 figs 46–48 (misidentified in part, only some females).
Diagnosis. Males and females of M. infelix can be distinguished from other species of the genus by the lack of a median black line and lateral black bands on the carapace (Fig. 1A, B). Males of M. infelx resemble the males of M. lemniscata and M. sucre Levi 1997, by the proximal branch of the terminal apophysis covering the tip of the distal branch of the terminal apophysis in mesal view (Fig. 1C, Levi, 1997: fig. 38). It can be separated from the males of M. lemniscata and M. sucre by the rounded tip of the proximal branch of the terminal apophysis (Figs 1C, 2A), which is truncated in M. lemniscata (Fig. 14C), and acuminate in M. sucre (Levi, 1997: fig. 38). M. infelix also can be differentiated by the less developed tegular keel (Figs 1C, 2A, 3A), which is well developed in M. lemniscata (Fig. 14C, D). It can also be diagnosed by the wide proximal branch of the terminal apophysis (Levi, 1997). Females are most similar to M. lemniscata based on the shape of the epigynum, which have a deep cavity created by the epigynum hood in both species. M. infelix can be distinguished by the presence of a strong, sclerotized median septum on the posterior cavity of the epigynum (Fig. 7C; see also Levi 1997: figs 11, 47), which is membranous in M. lemniscata. It can also be distinguished from M. leminiscata and other species of the genus by the presence of a fracture line on the epigynum hood (Figs 4A–C, 5A, B, 6B, D, E, 7A–D).
Description. Male. Colour and measurements described by Levi (1997: 230), under Mecynogea chavona. Male palp (based on specimen from Santana do Riacho, Minas Gerais, Brazil, UFMG 1739): terminal apophysis with a very developed and sclerotised proximal branch, which covers the apex of the distal branch in mesal view (Figs 1C, 2A). Proximal branch with a longitudinal depression holding the embolus, which is long and very thin (Figs 2C, 3A–B). Conductor well developed, strongly sclerotized and fused to ventral margin of tegulum (Figs 1D, 2A–B, 3A). Internal branch of terminal apophysis elongated, gently sinuous and acuminated apically, hidden by the terminal apophysis branches (Fig. 3A, B). Radix translucent and very poorly sclerotized (Figs 1C, 2A, B). Paracymbium small, apically rounded (Fig. 3A).
Female from Serra da Calçada, Minas Gerais, Brazil (IBSP 63237). Carapace orange without black bands (Fig. 1A). Chelicerae proximally orange, gradually darker distally. Endites and labium dark brown proximally and white distally. Sternum orange with dark lateral blots. Palp light orange. Legs orange, first and second femur with a dorsal, longitudinal black line (Fig 1A). All femora orange, darker ventrally. Coxae orange, with black markings on the second, third and fourth. Opisthosoma with a pair of anterior humps and an elaborated colour pattern, which shows a pair of black anterior markings; a longitudinal, median black mark with a transverse black bar, and two posterior black blots in a longitudinal red band with a trident shape pattern (Fig. 1A). The dorsolateral and lateral sides show a reticulated black background with white sinuous stripes. Venter bearing black stripes, with a pair of longitudinal white bands and four white markings around the spinnerets. Total length 9.60; carapace 3.80 long, 2.90 wide in the thoracic area, 1.30 wide after the posterior median eyes. Femur I length 5.0, patella 1.50, tibia 3.70, metatarsus 4.70, tarsus 1.50. Patella II 1.50, III 1.00, IV 1.40. Tibia II 3.10, III 1.5, IV 2.90. Epigynum projected ventrally, atrium with large, slit-shaped posterior openings. The posterior margin of the hood is folded, entering the atrium, forming an inner fold (Figs 4B, D–E, 5B–D, 8A–C) creating the cavity of the inner fold visible in the ventral view (Fig. 7C). Epigynum shows a sclerotized median septum that originates on median plate. Copulatory openings situated at the sides of median septum (Fig. 7C). Spermathecae divided in two receptacles (Fig. 8A, B), one small proximal and another larger and sock-shaped (Fig. 8C). Copulatory ducts emerge medially between larger spermathecae receptacles, folded, passing dorsally to the large receptacles (Fig. 8A, B). Both spermathecae receptacles show several small and large pores (Fig. 8D). Fertilization ducts connected proximally to spermathecae, near proximal receptacle (Fig. 8C).
Variation. Three of the seven females from Serra do Cipó have an entire epigynum with a rounded hood, which hides the atrium with the copulatory openings. The remaining females, from Brasilândia de Minas, Serra da Moeda and four specimens from Serra do Cipó lack the apex of the epigynum. The total length of females varies from 7.20 to 10.13 (n, 4).
Remarks. M. infelix was described based on a single female from Mato Grosso, central-western Brazil (Soares & Camargo 1948), and was considered by Levi (1997) as a junior synonym of M. bigibba based on the examination of the both species’ type material. In this same study, he described M. chavona based on a single male from Meta, Colombia.
We have found on the UFMG collection a sample of seven males and seven females collected together (UFMG 1739). The males match perfectly the diagnosis of M. chavona. However, the females show a very weird genital pattern. Three of them have an epigynum similar to those of M. lemniscata (Levi, 1997: figs 46–48) and of the holotype of M. infelix (Levi, 1997: figs 13–14), which have a deep cavity created by the epigynum hood. However, they differ from M. lemniscata by having a sclerotized medium septum on the epigynum, and by lacking the median black line and the black bands on the carapace edges. The holotype of M. infelix shares the same features with those three specimens. The remaining four females apparently have their epigynum damaged, missing the apex, making them very similar to some females illustrated by Levi (1997: figs 10–12) as M. bigibba. Those specimens considered by Levi as a variation of M. bigibba matched better the holotype of M. infelix than the holotype of M. bigibba by having a posterior atrium in the epigynum rather than the small posterior bulge seen in M. bigibba, leading us to reconsider the synonymy between M. bigibba and M. infelix.
Additionally, because we have found seven males that match the description made by Levi (1997), which are identical to the holotype of M. chavona, and were collected together with seven females that match the M. infelix holotype, we concluded that M. chavona should be considered a junior synonym of M. infelix.
Natural History. Several female specimens examined for this study have mutilated epigyna, in which the apex has apparently been removed (Figs 5A–C, 7A–D). The break in the epigynum coincides with an apparent fracture line (Fig. 4A–C). The mutilation of female epigynum during or after copulation has been reported for other araneid genera, and has been seen as a male strategy to prevent subsequent female mating events with other males (Mouginot et al. 2015, Nakata 2016). We think this explanation could possibly apply to M. infelix. We also noted cell clumps in the epigynum surface of different specimens, particularly on the fracture line (Figs 6C, F–H, 7E–F). These cells resisted the enzymatic cleaning treatment, indicating a chitin cell wall. The cells in our images are similar to the conidia of Beauveria bassiana, an entomopathogenic fungus (Wakefield 2006: fig 3a–d). It is unclear at this point whether these apparent fungal cells have any importance for the female epigynum mutilation, or if they simply spread on the fracture line.
Regarding the male copulatory apparatus, the shape and position of the proximal branch of the terminal apophysis suggest it could act as a functional conductor during copulation. Additionally, the remarkable size and sclerotization, as well as the folded shape of this sclerite (Fig. 2C) could indicate it is somehow related to female epigynum mutilation.
Distribution. This species is distributed mostly in the Neotropical savannas, including the Colombian llanos, which represent the northernmost record of the species. In Brazil, it can be found in the Distrito Federal, Minas Gerais, and Mato Grosso (Fig. 16).
Additional material examined. BRAZIL: Distrito Federal: Brasília, São Francisco, Lago Paranoá [15°50'41.16"S, 47°50'17.75"W], 1038 m, I.1978, 1 ♀, (MZSP 70592); Minas Gerais: Brasilândia de Minas, Fazenda Brejão [17°1'9.72"S, 46°54'59.81"W], 4.IV.2004, R.A.F. Redondo & F.A. Perini leg., 5♂ 1♀ (UFMG 1536); Diamantina [18°14'58"S, 43°36'1"W], 1236 m, 2♀ 1 juv. (MNRJ 2331); Moeda, Serra da Moeda [20°20'1.16"S, 44°3'18.82"W], 809 m, 1♀, 20.V.2006, E.S.S. Álvares leg. (IBSP 63237); Santana do Riacho, Parque Nacional da Serra do Cipó [19°20'57"S, 43°37'10.16"W], 822 m, I.2004, E.S.S. Álvares leg., 5♂ 2♀ (UFMG 1739); 1♀ (UFMG 19542); 1♀ (UFMG 19543); 1♂ (UFMG 19890); 1♀ (UFMG 19891); 1♀, (UFMG 19892); 1♂ (UFMG 19893), ditto, Portaria Palácio (19°15'0"S, 43°31'0"W), 1200 m, 10.XII.2001, E.S.S. Álvares & E.O. Machado leg., 1♂ (UFMG 1364).
description: Published as part of Martins, Pedro H. & Santos, Adalberto J., 2018, Morphology and taxonomy of the orb-weaving spider genus Mecynogea, and a peculiar species of Argiope (Araneae, Araneidae), pp. 423-451 in Zootaxa 4415 (3) on pages 424-432, DOI: 10.11646/zootaxa.4415.3.2, http://zenodo.org/record/1242066