Friesea multiclavata, 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 : 2-3

Friesea multiclavata sp. nov. Figs 1-6, 7-9, Tab. 1

Description

Body length: 0.51 mm (Holotype). Habitus cylindrical and robust, typical of Friesea . Color bluish-gray with ventral of head, legs and sternites white. Secondary granules moderately developed. Antennae shorter than cephalic diagonal. Ratio antenna: cephalic diagonal = 1: 1.4. Ant IV with apical bulb simple and subapically displaced on ventral side; subapical organite, dorsolateral S-microchaeta and 6 S-chaetae present dorsally (Fig. 1). Sensory organ of Ant III formed by five S-chaetae: two internal S-microchaetae bent externally and freely exposed; two subcylindrical guard S-chaetae and one smaller ventral S-microchaeta (Fig. 2). Ant I with 7 simple chaetae and Ant II with 11 chaetae, of which 10 are simple and one is strongly spatulate dorsoexternally (see detail in Fig. 7).

Head with 8+8 eyes in heavily pigmented eye-patch. Mandible strong with 5 unequal teeth; basal tooth measuring approximately twice the size of the others; maxilla head typical of the genus, with three lamellae; internal lamella with about 6 denticles (Fig. 3). Buccal cone short; Pre-labral/labral chaetae arranged according to the formula: 2/5,5,4. Labium typical of the genus, with papillated chaeta L, chaeta F about twice the length of E (Fig. 4).

Chaetotaxy of legs I, II, III. Subcoxae I 1,3,3; Subcoxae II 0,2,2; Coxae 3,6,7; Trochanters 5.4,4; Femora 11,10,10; Tibiotarsi 18,18,17, without M chaeta. Tibiotarsi I-III with 4,5,5 clavate tenent hairs, respectively (2 dorsal and 2 ventral on Tita I; 3 dorsal and 2 ventral on Tita II and III) (Figs 5, 6). Subcoxa I of legs I-III and lateral region of Abd V with hemispheric tegumentary protuberance constituted of primary granules (see detail of Fig. 7). Ungues toothless.

Dorsal body. Composed of short ordinary chaetae, slender S-chaetae, slightly longer than ordinary, and strongly clavate chaetae laterally on head and abdominal tergites IV-VI (Fig. 7). Head chaetotaxy composed of a0, d0, d2-5, sd1-5, oc1-3, c1-2, p1-2. Th I with 2+2 simple chaetae. Abd IV with 2+2 small clavate dorsolateral chaetae; Abd V with 2+2 long clavate dorsal chaetae; Abd VI with 10 strongly clavate chaetae arranged in three linear rows, as 4,4,2 (Fig. 7 and detail). Formula of S-chaetae by half tergite: 022/11111.

Ventral tube with 3+3 chaetae. Abdominal sternites II-V with 4+4, 5+5, 12+12, 5+5 chaetae, respectively (Fig. 8). Tenaculum and furca absent; furcal area with 2+2 microchaetae. Anal valves with 11-12 chaetae and one hr chaeta. Male genital plate with 2+2 pregenital chaetae, 4+4 eugenital and 9 circungenital chaetae (Figs 8, 9).

Material examined

Holotype male. BRAZIL, Amazonas State: Presidente Figueiredo municipality, forest leaf litter of Amazon Rainforest, coordinates 02°02'56"S, 60°06'08"W, 23.IV.2008, Hamada, Azevedo, Neiss, Silva & Meneses leg. (CM/ MNRJ slide number 2538).

Etymology

The specific name multiclavata is derived from Latin, meaning bearing nails, and is an allusion to the numerous clavate chaetae arranged along the tergites.

Remarks

Friesea multiclavata sp. nov. can be included in the reducta-group, which is composed of 14 species, according to Queiroz and Mendonça (2015), based on the following characters: 8+8 eyes and absence of furca and anal spines (Table 1). Despite the absence of anal spines, most species in this group, with the exception of Friesea africana Delamare Deboutteville, 1953, have some degree of chaetae modification on Abd VI. In this sense, the new species is unique within this group since it also presents modified chaetae on head and antennae.

Friesea multiclavata sp. nov. is very similar to Fr. albithorax Massoud & Thibaud, 1980 (Antilles), Fr. lobulata Palacios-Vargas & Díaz, 1986 and Fr. mucumontana Palacios-Vargas & Díaz, 1986 (Venezuela) mainly for sharing the 2+2 chaetae on Th I, clavate chaetae on body and 18,18,17 chaetae on tibiotarsi I-III. However, Fr. multiclavata sp. nov. has a simple apical bulb, 4,5,5 tenent hairs on tibiotarsi and ungues without teeth while Fr. lobulata has a trilobed apical bulb, only two clavate tenent hairs on legs I-III and toothed unguis. Friesea multiclavata sp. nov. is uniformly bluish-gray colored, while Fr. albithorax presents white thoracic tergites and the rest of the body is grey. Moreover, Fr. multiclavata sp. nov. is unique among the four species here referred, by the 10 strongly clavate chaetae on Abd VI, while the others have six ( Fr. lobulata and Fr. mucumontana ) or eight ( Fr. albithorax ) clavate chaetae.

Friesea multiclavata sp. nov. has an inconspicuous tegumentary protuberance on subcoxa I of legs I-III and ventrolaterally on Abd V (Fig. 7), also found in Fr. reducta and Fr. boitata . This structure was first mentioned by Massoud and Thibaud (1980) in specimens of Fr. reducta from Lesser Antilles. Later on, Fr. boitata was also found to possess the same structures on subcoxae I and Abd V. According to Queiroz and Mendonça (2015), it is possible that these structures were not mentioned in other descriptions as they may have not been properly visualized.

Although there are no phylogenetic studies for Neotropical species of Friesea , the proposition of a group relying on morphological similarities, such as reducta-group, represents the first step towards a better understanding of the genus’ morphological diversity in the biogeographical region. As proposed by Queiroz and Mendonça (2015), it is possible to distinguish “subgroups” of species within this group based on the number of chaetae on Th I, being 2, 3 or 4 by half tergite. Despite that, we believe that the striking resemblance of these species, especially those previously mentioned with 2+2 chaetae on Th. I, suggests close relationship between them.

While further studies may clarify phylogenetic relationships, comparative morphological studies are still the mainframe for species recognition. In this sense, all described species in the mentioned subgroup can be distinguished mainly based on body chaetotaxy, especially chaetae morphology, such as clavate chaetae. This character is considered to be consistent and, therefore, it is widely used, especially for recently described species.