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| Surazomus saturninoae
Ruiz & Valente, 2019
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Abstract
Surazomus saturninoae sp. nov. is described from eastern Amazon. The male has a pentagonal flagellum, similar to those of three other species in the genus. These four species are herein gathered as the arboreus-group of Surazomus. We present a brief synopsis of chaetotaxy description in hubbardiines and several homology proposals for the flagellum of the species in the arboreus-group: the posterior lobes may be homologous to the lateral lobes of hubbardiine species with trilobed flagella; the setal brush with 4–5 setae on the posterior lobe may be composed of one Dl2 seta and enlarged lobular microsetae; the single, median posterior coupling pocket may be homologous to the pair of posterior pockets seen in other hubbardiines; the single, median anterior coupling pocket may be homologous to the pair of pockets on the anterior border of the flagellum seen in other hubbardiines. Based on the morphology of these pockets and the chelicerae within Surazomus, we discuss the anchoring mechanism during the mating march.
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| Fig 1. Male holotype of Surazomus saturninoae sp. nov. (A) Lateral view. (B) Dorsal view. (C) Ventral view. |
The arboreus-group of Surazomus.
Within Surazomus, four species share features believed to be apomorphic and compose a species group, easily distinguished from the remaining species of the genus and traditionally recognized, but unnamed. To ease the discussion below, we herein propose the use of the informal name “the arboreus-group of Surazomus” to refer to that group.
List of species of the arboreus-group: Surazomus arboreus Cokendolpher & Reddell, 2000; Surazomus manaus Cokendolpher & Reddell, 2000; Surazomus paitit Bonaldo & Pinto-da-Rocha, 2007; and Surazomus saturninoae sp. nov.
Diagnosis. Species of the arboreus-group of Surazomus may be recognized by the males having pentagonal flagellum and bearing only two dorsal coupling pockets: one in front of Dm1 (AP), and another between Dm1 and Dm4 (PP), and by having a single large posterodorsal process on tergite XII (see Cokendolpher & Reddell [2000]: figs 11, 13, 20 and 23; Bonaldo & Pinto-da-Rocha [2007]: figs 2 and 3). Also, females have two pairs of slender, elongated spermathecal lobes with small bulbs followed by terminal constrictions (see Cokendolpher & Reddell [2000]: figs 14, 15, 24 and 25).
Surazomus saturninoae sp. nov.
Diagnosis from other species of the arboreus-group. Male: the overall shape of the flagellum of S. saturninoae sp. nov. is similar to that of S. arboreus, but the flagellum is as wide as long in S. arboreus (see Cokendolpher & Reddell [2000]: figs 11–13), while it is wider than long in S. saturninoae (Fig 6A). Also, the posterior dorsal hood (or dorso-median eminence) of S. arboreus is far from the posterior border of the flagellum, while it is close to the border in S. saturninoae (Fig 9D, in red). The widest portion of the flagellum in S. paitit is close to its middle length (see Bonaldo & Pinto-da-Rocha [24]: figs 2–4), while the widest portion of the flagellum in S. saturninoae is near its anterior border (Fig 6A). The posterodorsal process of abdominal segment XII of S. manaus (see Cokendolpher & Reddell [2000]: figs 20–23) and S. saturninoae (Fig 6A and 6C) is long, but the flagellum of S. manaus has parallel sides with the posterior lobes much longer than the flagellum body, while the flagellum in S. saturninoae has oblique sides and shorter posterior lobes. Female is unknown.
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| Fig 2. Details of the male holotype of Surazomus saturninoae sp. nov. (A) Peltidia, dorsal view. (B) Prosomal sterna, leg coxae and pedipalps, ventral view. (C-D) Abdomen: (C) dorsal view, (D) ventral view. |
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| Fig 5. Pedipalp and flagellum of the male holotype of Surazomus saturninoae sp. nov. (A) Detail of left pedipalp, retrolateral view. (B-E) Flagellum: (B) dorsal view, (C) ventral view, (D) dorsolateral view, (E) and lateral view. |
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| Fig 9. Mating march in Surazomus. (A) Male dragging locked female by the flagellum (note female chelicerae in vertical position). (B) Hypothesis of the anchoring mechanism for the species with paired AP and paired PP (four supporting points). (C) Hypothesis of the anchoring mechanism for S. algodoal (three supporting points); (D) Hypothesis of the anchoring mechanism for the species of the arboreus-group (two supporting points). Color explanation: (green) male flagellum; (pink) female chelicerae (illustrated in lateral view for better visualization of the hypotheses of anchoring machanism); (orange) AP; (blue) PP; (red) hood. |
Etymology. The specific epithet honors our friend, arachnologist Dr Regiane Saturnino, who collected the holotype. Noun in genitive case.
Natural history. The single specimen was collected with pitfall trap in primary upland Amazonian Rain forest (Terra Firme) from Bagre, municipality in eastern Amazon, state of Pará, Brazil. Surazomus saturninoae sp. nov. is the third species of the genus collected from eastern Amazon. The two others were also collected from state of Pará, Brazil, S. paitit from the upland Amazonian Rain forest of Caxiuanã, and S. algodoal from the dry forest (Restinga) of Algodoal Island.
Gustavo R. S. Ruiz and Roberta M. Valente. 2019. Description of A New Species of Surazomus (Arachnida: Schizomida), with Comments on Homology of Male Flagellum and Mating March Anchorage in the Genus. PLoS ONE 14(3): e0213268. DOI: 10.1371/journal.pone.0213268