A reassessment of the Neotropical genus Pseudonannolene Silvestri, 1895: cladistic analysis, biogeography, and taxonomic review (Spirostreptida: Pseudonannolenidae)

Abstract

In order to provide a reassessment of the Neotropical genus Pseudonannolene Silvestri, 1895, a cladistic analysis, biogeographic analysis, and taxonomic review were conducted in the present work. For the cladistic approach, 91 morphological characters were scored for 53 terminals as the ingroup and 10 as the outgroup. Three synapomorphies support the monophyly of the genus: presence of a longitudinal suture on the promentum, penial bases partially fused, and the internal branch of the gonopods surrounding the telopodite; and two homoplastic transformations: the lateral lobe of the collum densely striated and setae present up to the apical portion of the prefemoral process on the first leg-pair of males. The genus Pseudonannolene is recovered as sister-group of Epinannolene Brölemann, 1903 (Pseudonannoleninae). A total of 226 occurrence points were recorded for Pseudonannolene, with the majority of records from the Chacoan subregion, composed by Araucaria Forest, Atlantic, and Parana Forest provinces. The biogeographical searches using the Geographically explicit Event Model recovered two biogeographic reconstructions (cost of 79 000), with the vicariance events occurring more frequently in the deep clades, whereas sympatry and points of sympatry occurred in more inclusive clades. The first reconstruction recovered four vicariances, 13 sympatries, 4 points of sympatry, and 21 founder events, and the second reconstruction recovered four vicariances, 12–13 sympatries, 4–5 points of sympatry, and 21 founder events. The genus Pseudonannolene comprises 56 species, including 8 new species herein described: P. alata sp. nov., P. aurea sp. nov., P. bucculenta sp. nov., P. curvata sp. nov., P. granulata sp. nov., P. insularis sp. nov., P. morettii sp. nov., and P. nicolau sp. nov.; P. brevis Silvestri, 1902 and P. rugosetta Silvestri, 1897 are regarded as species inquirendae; a neotype of P. alegrensis Silvestri, 1897 is here proposed with male described for the first time. The following taxa are synonymized: P. canastra Gallo & Bichuette, 2020 and P. saguassu Iniesta & Ferreira, 2013 with P. ambuatinga Iniesta & Ferreira, 2013; P. marconii Iniesta & Ferreira, 2013 with P. longicornis (Porat, 1888); P. chaimowiczi Fontanetti, 1996, P. gogo Iniesta & Ferreira, 2013, P. rosineii Iniesta & Ferreira, 2014, P. taboa Iniesta & Ferreira, 2014, and P. longissima Iniesta & Ferreira, 2014 with P. microzoporus Mauriès, 1987; P. tricolor gracilis Brölemann, 1902 and P. tricolor rugosus Schubart, 1945 with P. tricolor Brölemann, 1902; P. auguralis Silvestri, 1902 with P. rocana Silvestri, 1902; and P. abbreviata Silvestri, 1902 with P. typica Silvestri, 1895. P. inops Brölemann, 1929 is proposed here as new status from P. bovei inops. A dichotomous identification key is presented to facilitate the species identification.

Expanding the range of the troglobitic millipede Pseudonannolene ambuatinga Iniesta & Ferreira, 2013: insights into its distribution and conservation status (Spirostreptida, Pseudonannolenidae)

“…Pseudonannolene Silvestri, 1895 is the most diverse genus within the Neotropical Pseudonannolenidae Silvestri, 1895 (Spirostreptida), with 56 valid species (Iniesta et al 2023a). Most of Pseudonannolene species are found in Brazil, with a considerable number of populations inhabiting areas associated with subterranean environments (Iniesta et al 2023b).…”

“…Most of Pseudonannolene species are found in Brazil, with a considerable number of populations inhabiting areas associated with subterranean environments (Iniesta et al 2023b). Over the past few decades, there has been an increasing interest in the taxonomy of this genus in Brazil, particularly concerning groups that are widely distributed in karst regions, including those regarded as obligatory cave-dwelling species Ferreira 2013, 2014;Iniesta et al 2023aIniesta et al , 2023b. To date, Pseudonannolene includes three troglobitic species (sensu troglobiont/troglobiotic species or population-race by Sket ( 2008)): P. spelaea Iniesta & Ferreira, 2013 found in iron-ore caves in Pará state; P. ambuatinga Iniesta & Ferreira, 2013 in carbonate caves in Minas Gerais state; and P. lundi Iniesta & Ferreira, 2020 from a single carbonate cave also in Minas Gerais state (for more details, see Iniesta et al 2022Iniesta et al , 2023a.…”

“…Identifying Pseudonannolene species as exclusively cave-dwelling solely based on distributional data is a challenging task because most of them, whether troglobitic or not, are found in karst regions. However, three of the 56 species known for the genus exhibit morphological adaptations associated with specific ecological restriction to caves: decrease in body size compared to related epigean species, body depigmentation in adults, and an apparent reduction in the number of ommatidia (observed only in P. spelaea) (Iniesta et al 2023a). Physiological and biological adaptations related to the restriction to caves known for many other troglobiont invertebrate taxa are still undescribed for Pseudonannolene species, as well as for any other millipede in Brazil.…”

“…The exhaustive mineral exploration in the region is the main threat and directly affects the species' habitat by potentially causing degradation to or even destruction of the caves (ICMBio 2018). The latest taxonomic review of the genus determined that P. ambuatinga has two junior synonyms: P. saguassu Iniesta & Ferreira, 2013, and P. canastra Gallo & Bichuette, 2020(Iniesta et al 2023a). The synonymization of these taxa added to the species' geographic distribution by providing additional occurrences (Iniesta et al 2023a).…”

“…The latest taxonomic review of the genus determined that P. ambuatinga has two junior synonyms: P. saguassu Iniesta & Ferreira, 2013, and P. canastra Gallo & Bichuette, 2020(Iniesta et al 2023a). The synonymization of these taxa added to the species' geographic distribution by providing additional occurrences (Iniesta et al 2023a). Additionally, since its description, additional specimens have been found at new locations, which has resulted in considerable changes to the known distribution of P. ambuatinga.…”