Mitogoniella modesta (Perty, 1836)

Ázara, Ludson Neves De, Dasilva, Marcio Bernardino & Ferreira, Rodrigo Lopes, 2013, Description of Mitogoniella mucuri sp. nov. (Opiliones: Gonyleptidae) and considerations on polymorphic traits in the genus and Gonyleptidae, Zootaxa 3736 (1), pp. 69-81 : 78-79

Mitogoniella modesta (Perty, 1836)

New Records: Brazil. Alagoas: Murici (MZSP 31237); Quebrangulo (REBIO Pedra Talhada), (MNRJ 31239). Bahia: Elísio Medrado (RPPN Jequitibá), (MNRJ 07701). Pernambuco: Caruaru (P.N.M. João Casconcelos Sobrinho), (MZSP 31310); Jaqueira (RPPN Frei Caneca), (MZSP 56036).

Mitogoniella indistincta was hitherto known to occur in six localities of the east-central region of Minas Gerais State (DaSilva & Gnaspini 2010). The present work adds 13 localities to the species distribution ( Fig. 6 ). These new occurrences expand its range widely northward and southward, onto high altitudes of the leeward side of Serra da Mantiqueira moutain range (up to 2200m). Mitogoniella taquara was known to Itatiaia, in Rio de Janeiro State, and to three localities of Minas Gerais (DaSilva & Gnaspini 2010). Currently, new occurrences expand the species range widely northward, beyond the limits of Atlantic Rain Forest biome, in the Cerrado biome ( Fig. 6 ). However, it is unlikely that those populations live in the open savannah vegetation, since Goniosomatinae is restricted to forestal physiognomies. Actually, these specimens were collected in caves that are common shelters for most species of Goniosomatinae (DaSilva & Gnaspini 2010). M. unicornis was hitherto known only from its type locality, Itororó, in Bahia State (DaSilva & Gnaspini 2010), now expanding to one nearby locality, Camacan ( Fig. 6 ). Mitogoniella modesta was hitherto known only from one locality, Santa Luzia municipality, in Bahia State (type locality unknown; DaSilva & Ganspini 2010). Five new occurrences expand the species range widely northward to Alagoas and Pernambuco States ( Fig. 6 ). The new occurrences are farther north from those of Bahia and actually widely expand the distribution of the subfamily (now occurring from Pernambuco to Santa Catarina States).

Mitogoniella mucuri sp. nov. occurs in a gap for harvestmen distributions (Pinto-da-Rocha et al. 2005; DaSilva & Pinto-da-Rocha 2011), in northeastern Minas Gerais State around the upper Mucuri River, between M. indistincta occurrences in Minas Gerais and M. unicornis occurrences, in Bahia, besides a single record in southern Minas Gerais ( Fig. 6 ).

Recent works have presented a historical biogeographical scenarios for the Atlantic Rain Forest using harvestmen distributions, including Goniosomatinae (Pinto-da-Rocha et al. 2005; DaSilva & Pinto-da-Rocha 2011). Harvestmen living in this biome have very restricted ranges and about 97% of endemism in Atlantic Rain Forest (especially Goniosomatinae, whose all species are endemic). From 36 species of the subfamily, 32 are restricted to one of the areas of endemism proposed by Pinto-da-Rocha et al. (2005) and DaSilva and Gnaspini (2010). Those areas probably originated by the uplift of mountain ranges and the resulting Pleistocene refuges of forest and marine transgressions in large river valleys (DaSilva & Pinto-da-Rocha 2011). Goniosomatinae speciated with those events, especially due to their association with humidity, high phylopatry and low vagility (DaSilva & Gnaspini 2010).

New occurrences of Mitogoniella species do not corroborate previous delimitation of areas of endemism, except for M. unicornis , restricted to Bahia area. This species was one of those used by DaSilva and Pinto-da- Rocha (2011) to form the Congruence Core of this area of endemism. Mitogoniella indistincta lives in south Serra do Espinhaço area of endemism (DaSilva & Pinto-da-Rocha 2011), the only one totally composed of Semideciduous Seasonal Forest, but with a range much wider than other endemic harvestmen species living there ( Fig. 6 ). Mitogoniella modesta lives in the Bahia and Pernambuco areas of endemism, i.e., a widespread species in northeastern Brazil, with a range spreading throughout important barriers for animal and plant forest species, such as the São Francisco River and Baía de Todos os Santos (e.g., Prance 1982; Silva & Casteleti 2005; Carnaval & Moritz 2008; DaSilva & Pinto-da-Rocha 2011). Mitogoniella taquara is restricted to Serra da Mantiqueira mountain range and the adjacent interior plateau, but the mountain range is not demonstrated as an area of endemism, since there is not enough congruence among endemic species ranges (unpublished data). Thus, Mitogoniella taquara lives in Itatiaia, the core of Serra da Mantiqueira, but much northward into the Cerrado biome. Other harvestmen species restricted to this region also live in Itatiaia, but with unique ranges in the interior of Minas Gerais State (DaSilva & Pinto-da-Rocha 2011 and unpublished data). We can infer from this pattern a scenario that contradicts the hypothesis of a common geographical origin of these species ranges, as in the area of endemism hypothesis, but isolated biological expansions from the more humid coastal areas of Atlantic Rain Forest or Serra do Espinhaço area of endemism. In glacial periods, marked by colder and drier weather, the Atlantic Forest reduced to mountain range slopes and coastal areas and probably its biota followed it (e.g., Ab´Saber 1982; Ledru et al., 2005). However, some works have shown asymmetry and asynchrony in these changes, as evidence of moist and cold periods in some areas, as in northeastern region (Oliveira et al. 1999). Thus, the present Semideciduous forest was probably substituted by Cerrado savannah in drier periods. With moist periods, species could spread over this “new” interior forest, and could speciate, as would have happened with M. taquara and other endemic species of Serra da Mantiqueira area.

Mitogoniella mucuri sp. nov. was recorded in a region poorly known for harvestmen, the northeast region of Minas Gerais State, plus in southern Minas Gerais. This distribution is unexpected, since this southern occurrence is disjunct from others, overlaps two other species of the genus, and a complete allopatry among sister-species is by far the most common pattern in Goniosomatinae (DaSilva & Gnaspini 2010). This unexpected sympatry with M. taquara and M. indistincta strengthen the hypothesis of unique biogeographical histories of species living in interior forests or other non-allopatric speciation modes.

Taxonomic studies on Opiliones contribute to ecological and behavioral studies, including those in caves, as shown by intensive work in recent years, especially with Goniosomatinae species (e.g., Gnaspini & Cavalheiro 1998; Machado & Oliveira 1998; Machado et al. 2000; Machado 2002; Willemart & Gnaspini 2004; Ferreira et al. 2005; Buzatto et al. 2007; Buzatto & Machado 2009). Harvestmen use caves as refuges during the day, form large aggregates on cave walls and leave them at night to forage in the epigean environment (Gnaspini 1995; Gnaspini et al. 2003; Machado et al. 2003; Willemart & Gnaspini 2004; Ferreira et al. 2005; Chelini et al. 2011). Therefore, Goniosomatine harvestmen are important in subterranean ecosystems, and a new species makes an immense contribution to the justification for conserving the caves in its type locality and, in general, eastern Minas Gerais State.

Figures

FIGURE 6. Geographic distribution of Mitogoniella species.