Rhodnius taquarussuensis, Rosa, Joao Aristeu da, Justino, Hernany Henrique Garcia, Nascimento, Juliana Damieli, Mendonca, Vagner Jose, Rocha, Claudia Solano, Carvalho, Danila Blanco de, Falcone, Rossana, Oliveira, Maria Tercilia Vilela de Azeredo, Alevi, Kaio Cesar Chaboli & Oliveira, Jader de, 2017

Rosa, Joao Aristeu da, Justino, Hernany Henrique Garcia, Nascimento, Juliana Damieli, Mendonca, Vagner Jose, Rocha, Claudia Solano, Carvalho, Danila Blanco de, Falcone, Rossana, Oliveira, Maria Tercilia Vilela de Azeredo, Alevi, Kaio Cesar Chaboli & Oliveira, Jader de, 2017, A new species of Rhodnius from Brazil (Hemiptera, Reduviidae, Triatominae), ZooKeys 675, pp. 1-25 : 5-14

Rhodnius taquarussuensis sp. n. Figure 2

Holotype.

BRAZIL: Mato Grosso do Sul: Taquarussu; Residence, 22°29'07.7"S; 53°21'08.9'W, 10 November 2010 H. E. G. Justino. UNESP (♀).

Paratypes.

BRAZIL: Colony formed from eggs obtained from the holotype: Araraquara: Triatominae Insectarium of the Faculty of Pharmaceutical Sciences, Araraquara, January 3, 2017, J. A. da Rosa, UNESP (25 ♂ 25 ♀).

Additional paratypes.

CTIOC - Collection of Triatomines of the Oswaldo Cruz Institute, Rio de Janeiro - Brazil (2 ♂ 2 ♀). Entomological Reference Collection of the Faculty of Public Health - USP, São Paulo -Brazil (1 ♂ 1 ♀). Collection of the Institute of Entomology of the Metropolitan University of Education Sciences (IEUMCE), Santiago - Chile (2 ♂ 2 ♀).

Etymology.

The name Rhodnius taquarussuensis sp. n. was chosen because this species was found in the city of Taquarussu, Mato Grosso do Sul, Brazil.

Diagnosis.

Rhodnius taquarussuensis sp. n. is close to R. neglectus , their differences being the color and a variety of morphological, morphometric and cytogenetic characters (Tables 1, 2). The general color of R. taquarussuensis sp. n. is brown, whereas R. neglectus is dark brown, almost black. This difference is particularly noticeable on the hind wings. The stridulatory sulcus of R. taquarussuensis sp. n. is brown at the base and black on the sides, whereas on R. neglectus it is completely black.

On the head, differences were noticed on the vertex, genae, antennae and triangular furrow of the first segment of the rostrum. The vertex of the head of R. taquarussuensis sp. n. is quite visible, whereas on R. neglectus it is not (Fig. 3A, B, D, E). The genae of R. taquarussuensis sp. n. are longer than those of R. neglectus (Fig. 3A, D).On R. taquarussuensis sp. n. the 10th part of the second segment of the antenna is brown; on R. neglectus , though, only the basis has that color. The triangular furrow of the first segment of the rostrum, towards the second segment, ends in a filamentous way on R. taquarussuensis sp. n. and in a rounded way on R. neglectus (Fig. 3C, F). On the thorax, differences can be found on the pronotum, wings, scutellum, prosternum, mesosternum and metasternum (Figs 4, 5). The membranous portion of the hind wings is brown on R. taquarussuensis sp. n. and dark brown on R. neglectus . The scutellum ends in a rounded apex on R. taquarussuensis sp. n. and in a filamentous apex on R. neglectus (Fig. 4A, B). On R. taquarussuensis sp. n. the apex of the scutellum covers the final portion of the urotergite I process, while on R. neglectus the apex of the process of the urotergite I is perfectly visible (Fig. 4A, B). The lines limiting the stridulatory sulcus are straight on R. taquarussuensis sp. n. and narrowed in the anterior third on R. neglectus (Fig. 5A, B). On R. taquarussuensis sp. n. the basis of the stridulatory sulcus is brown and the sides are black, whereas on R. neglectus the entire stridulatory sulcus is black. The central region of the limit between the mesosternum and the metasternum is regular and half-moon shaped on R. taquarussuensis sp. n., while on R. neglectus it is pronounced and slightly irregular (Fig. 5C, D). The beginning of the metasternum is narrow on R. taquarussuensis sp. n. and wide on R. neglectus (Fig. 5C, D). The ventral abdomen of R. taquarussuensis sp. n. is light brown, and that of R. neglectus is dark brown (Fig. 2). The terminal portion of the paramere of the male genitalia of R. taquarussuensis sp. n. is thinner than that of R. neglectus (Fig. 9A, C). The dorsal phallothecal sclerite has a trapezoidal shape on R. taquarussuensis sp. n. and is rounded on R. neglectus (Fig. 8C, D). The external limit of the 10th segment of the dorsal side of the female external genitalia of R. taquarussuensis sp. n. presents a concavity in the middle portion, whereas on R. neglectus that limit is straight (Fig. 6A, B). From posterior view, the limits of the 9th segment with gonocoxite VIII are curve on R. taquarussuensis sp. n. and straight on R. neglectus , and the superior line limiting the 10th and 9th segments is straight on R. taquarussuensis sp. n. and curve on R. neglectus (Fig. 6C, D). In the ventral side of the female external genitalia of R. taquarussuensis sp. n. there is a concavity in the external limit with the 10th segment that is also noticed from dorsal view; on R. neglectus that limit is a straight line. From ventral view, the external limits of the 9th segment of the female external genitalia are curve on R. taquarussuensis sp. n. and straight on R. neglectus (Fig. 6E, F).

Among the 19 characters measured, 12 showed significant differences between R. taquarussuensis sp. n. and R. neglectus in both sexes and also the eggs of both species. Two characters showed differences only between males, and five characters did not show significant differences (Tables 1, 2).

Description.

A total of 15 adult females and 15 adult males of R. taquarussuensis sp. n. and R. neglectus were measured, as well as 30 eggs shells of both species. Such measurements are detailed in Table 1.

The head of R. taquarussuensis sp. n. has a prominent brown vertex contrasting with the black sides. The clypeus is well defined. The genae are large, visible and dark brown, moving towards the anteclypeus (Figs 2A, C, 3 A, B). The limits between the genae and the clypeus are brown.

The first segment of the antennae is black with mixes of brown. The articulation between the first and second segment of the antennae is brown. Roughly all the 10th part of the beginning of the second antennal segment is brown. The second segment is mostly black. In the articulation between the second and third antennal segment there is a black ring followed by a brown one. The beginning of the third segment (around 1/3) is black and the remaining portions (2/3) are brown. The articulation between the third and fourth antennal segment is brown. The beginning of the fourth segment is black and the remaining portions are brown with mixes of black (Fig. 2A, C).

The eyes are black and the ocelli are brown. The neck has a brown central dorsal strip flanked by two (1+1) black, narrower strips. The ventral portion of the neck between the ocelli is dark brown (Fig. 2A, B, C, D).

The pronotum of the thorax of R. taquarussuensis sp. n. has a trapezoidal shape and is limited by a brown carina. In the antero posterior direction the pronotum has other two brown carina in the middle portion and six black strips. The three carina and the three brown strips are interspersed with the six black strips, which are larger. The collar (first portion of the pronotum) in the central part is brown and is followed by two (1+1) black glabrous areas and the two (1+1) antero lateral angles. The anterior portion of the pronotum consists of three anterior lobes which are clearly distinct from the posterior portion (hindlobe). Those three anterior lobes are limited by the carina and on each of them there are two black glabrous areas with a lengthy and irregular outline (Fig. 2A, C).

The cuticle involving the veins of the hemelytron is light brown. The corium between the veins of the coriaceous region is dark brown, whereas that of the membrane is brown (Fig. 2A, C).

The prosternum contains the stridulatory sulcus, which moves along that segment in an antero-posterior direction, having a brown color in the background and black on the sides. Two elongated tubercles limit the anterior half of the stridulatory sulcus. In the superior portion and in diagonal direction from the tubercles there are two black glabrous areas surrounded by a set of brown sensilla (Fig. 5A).

The mesosternum is limited anteriorly by the prosternum and posteriorly by the metasternum, both limits being brown. The central line dividing two dark brown elevations is also brown. Those two elevations are limited by two (1+ 1) black side glabrous areas diagonally placed. The central region of the posterior limit of the mesosternum has a half-moon shape. The metasternum is brown and resembles an isosceles triangle. Its anterior portion, i.e., its limit with the mesosternum, corresponds to the vertex of the triangle and is narrow, whereas its posterior portion, i.e., its limit with the first abdominal segment, corresponds to the basis of the triangle (Fig. 5C).

The three pairs of coxae are brown, except for the black glabrous areas. The trochanters of the anterior pair of legs are brown, but mixed with black glabrous areas. The middle and posterior pairs of trochanters are brown and have no glabrous areas. The three pairs of femora are black and the same color prevails in the three pairs of tibiae, except in the articulations with the femur and the spongy fossula, which are brown. The spongy fossulae are located in the first and second pairs of legs in the final portion of the tibia, alongside the articulations with the tarsi (Fig. 2A, B, C, D).

The abdomen of R. taquarussuensis sp. n. presents a brown color in the longitudinal central portion. On the sides of each segment there are (3+3) black glabrous areas, which are mixed with brown and black areas. The connexivum of the dorsal portion lies between the second and seventh segment. For each of those segments the anterior half is black and the posterior one is brown. The dorsal connexivum, also lying between the second and seventh segment, has a black color in 2/3 of the anterior portion, but that black color ends in an irregular way over the remaining 1/3, which is brown. Therefore, the black portion of the connexivum presents two edges moving towards the brown portion: one in the internal limit of the connexivum and the other in the middle portion. However, the connexivum of the second dorsal segment is black in the anterior half and brown in the posterior one, the limit between the portions having a diagonal shape. The seventh segment, on the other hand, is practically all black, except for a small brown strip located in the external posterior half. Type 1 sensilla, which prevail on the head, thorax and abdomen, have a brown color (Fig. 2B, D).

Male genitalia have the typical aspect of the genus Rhodnius . The median process of the pygophore (PrP) is short and triangular, but the base is broad and the sides are elongated with a thin edge. Parameres are hairy with a thin edge. From ventral view, the phallosome (Ph) has a broad plate whose superior region has a trapezoidal shape and occupies the middle region of the aedeagus. The support of the phallosome plate (PrPh) is broad. Conjunctival process I (PrcjI) is present and II (PrcjII) is absent. Endosomal process (En) is well-developed when seen from dorsal and ventral view (Figs 8A, C, 9B).

The dorsal side of the female external genitalia presents a concavity in the middle portion of the 10th segment. Seen from posterior view, the limits (1+1) of the 9th segment with gonocoxite VIII are curve, whereas the superior line limiting the 10thand 9thsegments is straight. In the central portion of the 10th segment of the ventral side of the female external genitalia there is another concavity that can be noticed from dorsal view. The external limits (1+1) of the 9th segment of the female external genitalia are curve when seen from ventral view (Fig. 6A, C, E).

Egg shells of R. taquarussuensis sp. n. have a length of 1.72 mm and an opercular opening of 0.49 mm. They present lateral flattening, collar and exochorion cells, most with pentagonal or hexagonal shape (Fig. 7A, C).

Finally, although R. taquarussuensis sp. n. showed the same number of chromosomes as R. neglectus and all the tribe Rhodniini , i.e., 2n = 22 (Figure 11B), the constitutive heterochromatin pattern and the composition of the pairs of bases of DNA rich in AT and CG were completely different from R. neglectus , as the analysis of the nuclei of the initial prophases of R. taquarussuensis sp. n. has revealed a chromocenter consisting of sex chromosomes (arrow) and several heterochromatic blocks dispersed in the nucleus (Fig. 11A). The analysis of metaphase I of R. taquarussuensis sp. n. has demonstrated that this triatomine has heterochromatic blocks in both extremities of practically all the autosomes and in the Y sex chromosome (Fig. 11B), unlike what has been recently stated for many populations of R. neglectus that do not present heterochromatin in autosomes ( Alevi et al. 2015a). Furthermore, R. taquarussuensis sp. n. has the X sex chromosome rich in CG (Fig. 12C), the Y rich in AT (Fig. 12D) and various blocks rich in CG dispersed in the prophase nucleus (Fig. 12C), while R. neglectus only has the X sex chromosome rich in CG (Fig. 12A) and the Y rich in AT (Fig. 12B), which proves the genetic differences between the two Rhodnius species.