A new species of Dicranocentrus Schött (Collembola, Entomobryidae, Orchesellinae) from Brazilian Amazon

Abstract

Orchesellinae specimens are distinguished from other Entomobryidae by a shorter fourth abdominal segment (length at the midline less than 1.8 times the third segment), generally more than four antennal segments, recurved labral setae and the presence of a complex metatrochanteral organ, with at least 11 spine-like setae, (Soto-Adames et al. 2008). Adult Dicranocentrus Schött specimens have the following characters: antennae with six segments, both fifth and sixth antennal segments annulated, 8+8 lenses in the eye patches, absence of a postantennal organ, apically rounded and/or truncated scales, pre-labral setae simple, not bifurcated, rows of spines on dens (present in most but not all species) and mucro bearing two teeth with a basal spine (Mari-Mutt 1976, 1981, Arlé & Mendonça 1982, Bellinger et al. 1996–2012). The genus is similar to other scaled Orchesellini genera such as Pseudodicranocentrus Mari-Mutt, 1981 and Dicranorchesella Mari-Mutt, 1977, but differs from these taxa by the presence of simple pre-labral setae (bifurcated in Pseudodicranocentrus) and by rounded and/or truncated scales (fusiform and apically pointed in Dicranorchesella) (Mari-Mutt 1977, 1980). Dicranocentrus is holotropical in distribution only four species recorded from Brazil: D. bicolor Handschin, 1924, D. silvestrii Absolon, 1903, D. termitophilus Handschin, 1924 and D. heloisae Arlé & Mendonça, 1982 (Abrantes et al. 2012). These species are restricted to northeastern and southeastern Regions (Abrantes et al. 2012). The new species is the first from Brazilian Amazon, north region of Brazil. The dorsal chaetotaxic scheme follows that of Mari-Mutt (1979).

A Survey of the Brazilian Dicranocentrus Schött (Collembola, Orchesellidae, Heteromurini) with the Description of a New Species and Notes on the Genus

“…The description of Dicranocentrus amazonicus is succinct as to most species of the genus, and some diagnostic features are unknown or unclear to it, such as the presence and distribution of smooth chaetae on antennae, tibiotarsi and furca, trunk sens formula, antennal and ventral head chaetotaxy (except labial and maxillary outer lobe chaetotaxy), number of tenaculum chaetae, as well as other features. The labral papillae shape and position and absence of scales on ventral tube are also unlikely characters and should be better investigated in this species [ 17 ]. Nevertheless, there are enough data to separate this species from other Brazilian and Neotropical taxa ( Table 2 and Table 3 ).…”

“…The genus’ main diagnostic features are antennae with six segments (antennal segments I and II subdivided), 8 eyes, prelabral chaetae simple (not bifurcate), ungues with a single outer tooth and dental spines, if present, simple (a detailed diagnosis is presented in the results topic) [ 12 , 14 , 15 ]. Currently, there are 11 species of Dicranocentrus known from Brazil, found in humid forested areas of Atlantic and Amazon forests domains ( Table 1 ) [ 6 , 13 , 16 , 17 , 18 , 19 , 20 , 21 ].…”

Redescription of Dicranocentrus heloisae Arlé & Mendonça, 1982 (Collembola: Entomobryidae)

“…The specie Dicranocentrus amazonicus Bellini, Morais & Oliveira, 2013, inserted into the marias-group (Bellini et al 2013), is characterized by Figures 11-16. Dicranocentrus heloisae Arlé & Mendonça, 1982.…”

“…The genus includes 63 species nowadays, of which most are derived from the Neotropical Region (Bellinger et al 2014;Xu & Zhang 2014). In Brazil, five species of this genus have been reported so far: D. bicolor Handschin, 1924 from Santa Catarina State, D. termitophilus Handschin, 1924 from Minas Gerais State, D. heloisae Arlé & Mendonça, 1982 Absolon, 1903 from Rio de Janeiro State (Abrantes et al 2012;Bellini et al 2013).…”

Two New Species and New Records of Springtails (Collembola: Entomobryidae, Paronellidae) from Nevis, Lesser Antilles

“…Species circumscription in the genus Dicranocentrus is based on the pattern of dorsal head and body macrosetae, which are traditionally represented as simple, diagrammatic distributional maps (e.g., Mari Mutt 1979;Bellini et al 2013). The nature of these maps often limits assessment of the homology of elements and may hide information that could help to distinguish species with similar numbers of macrosetae.…”