Furculanurida boiuna, Carolina da Rocha Neves, Ana, Cleide de Mendonca, Maria & Costa Queiroz, Gabriel, 2019

Carolina da Rocha Neves, Ana, Cleide de Mendonca, Maria & Costa Queiroz, Gabriel, 2019, Two new species and new records of Neanuridae (Hexapoda: Collembola) from Brazilian central Amazonia, Zoologia 36, pp. 1-8 : 3-6

Furculanurida boiuna sp. nov. Figs 10-15, 16-22, Tab. 2

Description

Body length 0.9 mm (Holotype). Habitus elongated and cylindrical, paratergites not developed. Secondary granules moderately developed. Color white, in ethanol. Antennae shorter than cephalic diagonal. Ratio antenna: cephalic diagonal = 1: 1.6. Ant IV with trilobed apical bulb, subapical organite apically displaced, next to apical bulb; 6 long S-chaetae (S1-S4, S8, S9?); dorsolateral S-microchaeta absent. Ant III and Ant IV dorsally fused. Antennal organ III with two inner small and curved S-microchaetae, two subcylindrical guard S-chaetae and one S-microchaeta ventrally; dorsal guard S-chaeta apically displaced, towards Ant IV and aligned to S2 and S3, and as long as S-chaetae of Ant IV (Figs 10, 11). Ant II with 11 chaetae and Ant I with 6 chaetae.

Head. Eyes absent, PAO circular with 8-9 vesicles, rosette-like (Fig. 12). Central head chaetotaxy with d1-5, sd3-5 (chaetae sd1,2 absent - probable homology), oc1-3, p1-3; c row of chaetae is absent. Maxilla styliform; Mandible with 7 teeth: 2 large basal, 3 subequal intermediate and 2 apical (Fig. 13). Pre-labral/labral chaetae arranged according to the formula: 4/2,3,5,2 (Fig. 14). Labium truncate with C and D chaeta apically displaced (Fig. 15).

Chaetotaxy of legs I, II, III. Subcoxa I 1,3,3; Subcoxa II 0,2,2; Coxa 3,6,8; Trochanter 6,6,6; Femur 12,12,11; Tibiotarsus 19,19,18; M chaetae basally displaced (Figs 16-18). Unguis of leg I with a strong basal tooth on inner edge (Fig. 16); unguis of legs II and III with small basal tooth on inner edge (Fig. 18).

Dorsal chaetotaxy of tergites consisting of simple, short and subequal chaetae and thin and long S-chaetae. Formula of S-chaetae by half tergite: 022/11111. Ratio ordinary chaeta: S-chaeta= 1: 4.5. Th I with 2+2 chaetae. Th II with dorsolateral S-microchaetae; Th II and III with one lateral ordinary chaeta posteriorly displaced. Abd VI with 8 chaetae, which 4 arranged in a row (Fig. 19).

Ventral tube with 3+3 chaetae. Abdominal sternites II-V with 2+2, 2+2, 5+5 and 3+3 chaetae, respectively (Fig. 20). Tenaculum with 3+3 teeth. Furca well developed: manubrium with 20 chaetae, dens with 5-6 chaetae; mucro with two lamellae and slightly curved apex (Fig. 21). Ratio mucro: dens = 1: 2.3. Each anal valve with 13 chaetae and 3 hr. Genital plate of male with 5+5 eugenital chaetae and 10 circungenital chaetae (Fig. 22).

Material examined

Holotype male. BRAZIL, Amazonas State: Manacapuru municipality, forest leaf litter of Amazon Rainforest, coordinates 03°12'23"S, 60°40'21,0"W, 29.III.2008, Nessimian, Querino, Pepinelli, Azevedo & Neiss leg. (CM/ MNRJ slide number 2523).

Etymology

The name of this species is a reference to the legendary Amazonian giant snake called Boiuna, in Amerindian Tupi Language. According to the legend, a huge snake grows to unrealistic proportions and, as it crawls through dry land, it leaves behind the grooves that later on become the Igarapés.

Remarks

The broadness and vagueness of the current diagnosis for Furculanurida was discussed in some studies involving species of this genus and its similarity to other genera ( Thibaud and Palacios-Vargas 2000, Queiroz and Fernandes 2011, Zon et al. 2014). Recently, Zon et al. (2014) drew attention to the fact that Furculanurida has a poor definition, with many morphological features overlapping with the diagnosis of Pseudachorutes Tullberg, 1871 and Stachorutes Dallai, 1973 (see Table 2). The most conflicting aspects are related to number of eyes, PAO shape and number of vesicles and furcal development, as well as antennal chaetotaxy, more specifically the presence/absence of dorsolateral S-microchaeta on Ant IV ( Queiroz and Fernandes 2011, Zon et al. 2014). Therefore, a revision of the genus is needed, along with a redescription of the type species, Fu. africana (Massoud, 1963).

According to Massoud (1967), Fu. africana has no eyes and no body pigments but has a well-developed furca. Regarding these characteristics, until now, Fu. emucronata Zon et al., 2014 was the only species similar to Fu. africana , except for the absence of mucro. In this sense, the new species Fu. boiuna sp. nov. represents the third in the genus without eyes and body pigment.

In relation to these three species, the most remarkable similarity among them is: the presence of a somewhat swollen branch of mandible and two basal strong teeth, although some minor differences can be observed in the total number of apical teeth. Furculanurida boiuna sp. nov., together with Fu. emucronata , has seven teeth on the mandible and the ungues exhibit a tooth on their inner edge, while Fu. africana mandible has nine teeth and the ungues are devoid of teeth.

Despite the mentioned similarities, Fu. boiuna sp. nov. shows a complete furca, while in Fu. emucronata it is incomplete, without mucro. Moreover, Fu. emucronata has 7 S-chaetae on Ant IV and between 13-16 vesicles on PAO of an elliptical shape, while Fu. boiuna sp. nov. shows 6 S-chaetae on Ant IV and 8-9 vesicles arranged in circular shape.

From a biogeographical point of view, the fact that the Neotropical Fu. boiuna sp. nov. is the first species outside of Africa with these set of characters is of considerable relevance. This indicates that a more widespread distribution, i.e. holotropical, is possible and raises questions regarding Pseudachorutinae distribution throughout the tropics. In this sense, despite their rareness, since few specimens are known from these three species, e.g., Fu. africana is known only by the holotype, these eyeless species are important for Pseudachorutinae taxonomy.

It must be highlighted that the new species clearly fits the recently proposed Arlesia -group of genera ( Queiroz and Zeppelini 2017). Except for an elongated Sgd, almost subequal to Ant IV S-chaetae, Ant III-IV chaetotaxy is doubtlessly similar to the mentioned group of genera. For example Fu. boiuna sp. nov. has trilobed apical bulb; absence of ms; presence of S1-4, S8 and S10; x chaeta between a1 and i chaeta; and apically displaced Sgd. Regarding head and thorax chaetotaxy, the pattern similarity is also evident. On head: the reduced sd chaetae, absence of c row of chaetae, as well as only p1-3 chaeta on head. On thorax: Th. I with only 2+2 chaetae; Th. II and III with one dorsolateral chaeta posteriorly displaced.

In the same sense, according to original illustrations provided by Zon et al. (2014) for Fu. emucronata , it is possible to recognize one main chaetotaxal difference from the proposed Arlesia group: the absence of one dorsolateral chaeta on Th. II and III, probably the posteriorly displaced one. However, regarding all other chaetotaxy features of Ant III-IV (S10 is interpreted as S9 by Zon et al. 2014), head (sd with fewer chaetae - sd2-5? - and c row absent) and tibiotarsi (although not drawn, M chaetae position is clearly basally displaced), it can also be placed inside the Arlesia group.

In short, as advocated by Queiroz and Fernandes (2011) and Zon et al. (2014), it should be reinforced that Furculanurida , now with 15 species (see Table 2), needs to be revised. We estimate that after such review, only these three species, Furculanurida boiuna sp. nov., Fu. emucronata and Fu. africana , would remain within the genus. However, further analyses must be made to stablish species relationships as well as their character evolution.