Zavrelimyia (Paramerina) ximenesae Dantas, Pinheiro & Hamada, 2025, sp. nov.
Creators: name: Dantas, Galileu P. S.
name: Pinheiro, Marcos P. G.
name: Hamada, Neusa
Publisher: name: Zenodo
Year: 2025
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Diptera
Chironomidae
Zavrelimyia
Zavrelimyia ximenesae

description: Zavrelimyia (Paramerina) ximenesae sp. nov.
urn:lsid:zoobank.org:act: 649A0B42-9D6F-4C92-AD18-0F5E8A55F514
Type material. Holotype: male with pupal exuvia, BRAZIL, Rio Grande do Norte, Parnamirim, Taborda river, 05º56’49”S / 35º14’07”W, 14.vii.2024, G.P.S. Dantas and M.P.G. Pinheiro (INPA). Paratypes: 2 males, as holotype except collected with a modified Shannon trap; a pupal exuvia, as holotype (INPA).
Diagnostic characters. Adult male: TI mostly pale, with anterolateral brown spots; TII– IV with a brown band on the anterior half; TV mostly pale, with faint brown lateral stripes; TVI– TVII mostly dark brown, with a pale posterior band; TVIII dark brown. Lateral vitta light brown, darker at the anterior end; dorsal half of MAII dark brown, ventral half pale; a distinct dark brown spot between AAII and Pp, and another on the anterior margin of the scutum. Foreleg with femur predominantly pale, with a slightly darker tone at the distal end, tibia and tarsus are dark brown. Gonostylus with two small outer preapical setae, each located in a pit. Pupa: TI – V without shagreen; internal margins of anal lobe without spines; genital sac extending beyond apex of the anal lobe.
Etymology: The name is a tribute to Dr. Maria de Fátima F. de Melo Ximenes, in recognition of her contribution to the study of insects in the Brazilian state of Rio Grande do Norte, where the new species was collected.
Adult male (n = 3)
Total length 2.79–2.97 [2.97] mm. Total length/wing length 1.80–1.96 [1.82]. Wing length/ profemur length 2.10– 2.26 [2.10].
Coloration. Head: antennae and palpomeres brown. Thorax: medial vitta light brown, lateral vitta light brown, darker at the anterior end, gradually becoming lighter toward the posterior end; the dorsal half of MA II is dark brown, while the ventral half is pale; there is a distinct dark brown spot between AA II and Pp, and another on the anterior margin of the scutum. Wings with unmarked membrane, covered with macrotrichia. Foreleg with femur predominantly pale, with a slightly darker tone at the distal end, while the tibia and tarsus are dark brown; mid and hind legs with femur predominantly pale, with a slightly darker tone at the distal end, tibia and tarsus faintly brownish. Abdomen: TI with anterolateral brown spots; TII–IV with a brown band on the anterior half; TV mostly pale, with faint brown lateral stripes; TVI–TVII mostly dark brown, with a pale posterior band; TVIII dark brown; hypopygium pale.
Head (Fig. 1B). Antenna: AR 1.71–1.83 [1.83], flagellum 1030–1145 [1145] µm long, apical flagellomere offset, conical, 65–80 [80] µm long, 23–25 [25] µm wide, pre-apical seta 60 [60] µm long, pedicel with 4–5 [4] setae. Eyes bare; dorsomedial extension well developed, 120–135 [120] µm long, 65–70 [70] µm wide, medially separated by 80–90 [80] µm. Temporal setae 14–15 [15], uniserial. Clypeus 90–105 [105] μm long, 80–90 [85] μm maximum width, with 17–27 [19] setae. Cibarial pump with anterior margin concave, 200–230 [230] μm long. Tentorium 140–180 [180] μm long. Palpomere lengths (I–V in μm): 36–50 [47]; 55–70 [65]; 145–180 [180]; 175–200 [200]; 215–280 [280].
Thorax (Fig. 1A). Acrostichals about 44–46 [46], biserial, diverging and merging with Dc posteriorly; dorsocentrals 30–36 [35], arranged in a multi-, bi-, and uniserial pattern in the anteroposterior direction; prealars 12–18 [16], multiserial; supraalar 1. Antepronotum with 1–2 [1–2] lateral setae and two small tubercles, one dorsal and one medial. Scutellum with about 25 [25] setae, triserial, with the posterior row composed of thicker setae and the two anterior rows of very fine setae.
Wing (Fig. 1C). Length 1.43–1.63 [1.63] mm, width 0.46–0.49 [0.48] mm. Membrane densely covered with macrotrichia; C slightly produced beyond apex of R 4+5 by 45–55 [55] μm. Brachiolum with 3 setae. Squama with 22–30 [30] setae. VR 0.84–0.90 [0.87].
Legs. Foretibia with one apical spur (Fig. 2A), 40–47 [47] μm long, bearing narrow, elongated main teeth and 3 side teeth. Mid tibia with an inner spur 60–75 [65] μm long, bearing narrow, elongated main teeth and 3 side teeth; an outer spur 30–42 [42] μm long, bearing a main tooth only slightly longer than the 3 side teeth (Fig. 2B). Hind tibia with an inner spur 65–75 [75] μm long, bearing narrow, elongated main teeth and 3 side teeth; an outer spur 35–40 [40] μm long, bearing a main tooth only slightly longer than the 3 side teeth (Fig. 2C); tibial comb with 6 bristles. All legs with slender, distally curved claws, each with basal spines. Lengths and proportions of male legs as in Table 1.
Hypopygium (Figs. 1D, 2D). Tergite IX without posterior row of setae. Anal point conical, 35 [35] μm long. Phallapodeme elongated and very distinct, strongly curved at the anterior end, 125–140 [140] μm long; sternapodeme with a strong oral projection, 30–32 [30] μm long. Gonocoxite 185–195 [195] μm long. Inferior volsella absent. Gonostylus slender, slightly curved, 130–145 [145] μm long, with two small outer preapical setae, each located in a pit (Figs. 1E, 2E); megaseta lanceolate, 13–15 [13] μm long. HR 1.34–1.44 [1.34]; HV 2.05–2.17 [2.05].
Pupa (n = 2). Total length 3.70–3.77 [3.77] mm (abdomen and thorax of male).
Coloration. The cephalothorax and wing sheath are mostly light brown, with some hyaline maculation as shown in Figure 3A. The thoracic horn has a transparent external membrane, except at the base, which is light brown; the plastron plate is pale brown, and the respiratory atrium is dark brown (Fig. 3B). The abdomen is as shown in Figure 3C; TI–TVIII are brown, with a light spot/band at the posterior/posterolateral margin; the anal lobe is light brown; the genital sac is hyaline at apex.
Cephalothorax. Dorsal surface smooth. Frontal apotome triangular, 170 [170] μm wide at base (Fig. 4B). Wing sheath smooth, 1025–1100 [1100] μm long, 380–390 [390] μm maximum width (Fig. 3A). Thoracic horn slightly arched, rounded at apex, external membrane with scattered spines (Figs. 3B, 4A), 250–275 μm long, 60–65 [65] μm maximum width; plastron plate small, rounded, 30–45 [30] μm long. Corona 65 [65] μm long. Respiratory atrium occupying about 80% of the thoracic horn volume, connected to the plastron plate by a distinct aeropyle 24–27 [24] μm long. Basal lobe well developed, 22–30 [22] μm high, 60–80 [60] μm wide at base; thoracic comb composed by 13–14 tubercles (Fig. 4A).
Abdomen (Fig. 3C). Tergite I with a distinct scar 180–195 [180] μm long; TI-V without shagreen; TVI–TVII with minute spines grouped near the anterolateral margin (difficult to see); TVIII with anterior field of fine shagreen; anal lobe with shagreen in the anterior half. Sternite I without shagreen; SII with a large field of shagreen composed by groups of 2–4 spine in the middle and isolate spines laterally; SII–VI with shagreen formed by isolated spines restricted to the paratergites; SVII with shagreen formed by fine spines restricted to the area around V 1 and V 3; SVIII with a wide shagreen field formed by isolated spines, except in the paratergites and median-posterior area, which are bare. Chaetotaxy of segments IV and V as in Figure 4C. Segment VII with 4 LS setae, all in the posterior half. Segment VIII with 5 lateral filaments. Anal lobe elongated (Fig. 3D, 4D), 360–390 [390] μm long, 225 [225] μm wide at base, with 2 lateral macrosetae; outer margins with 10–13 [10–11] small spinules; inner margin membranous, without spinules. Genital sac elongated, 395–420 [420] μm long, 170–180 [180] μm wide at base, extending beyond the apex of the anal lobe. GS/AL 1.08–1.10 [1.08].
The species is known only from the type locality in northeastern Brazil. Pupae were collected in association with aquatic vegetation in a backwater area of a sandy-bottom stream. Nascimento et al. (2019) recorded a morphotype of Zavrelimyia (Paramerina) based on larvae collected in the state of Pernambuco, Brazil, approximately 350 km away from the type locality of Z. ximenesae sp. nov., in an area with similar environmental conditions, both within the Atlantic Forest domain. It is possible that the larvae recorded by Nascimento et al. (2019) belong to Z. ximenesae sp. nov. However, this identification requires the association and description of the species’ larval stage.
Males of the subgenus Zavrelimyia (Paramerina) are distinguished by the following combination of character states: elongated tibial spurs, R 2 wing vein present, absence of a setal row on tergite IX (TIX), and a well-developed, anteriorly curved phallapodeme. The pupa is characterized by a combination of the genital sac extending beyond the apex of the anal lobe and by the absence of spines on the inner margins of the anal lobe. Both the male and pupa of the new species fit this diagnosis exactly and are, therefore, placed in Z. (Paramerina).
The morphology of the Z. (Paramerina) adult male is highly conserved, and generally, the wing, thorax, and abdomen color patterns are the main characteristics used in species identification (Roback 1971, Niitsuma et al. 2012, Mondal et al. 2022). Zavrelimyia ximenesae sp. nov. is similar to the neotropical species Z. (Paramerina) fasciata (Sublette & Sasa, 1994) and Z. (P.) smithae (Sublette, 1964), sharing similarities in male abdominal color pattern. However, the male of these species can be differentiated by the color pattern of the abdominal tergites, thorax, and legs. In the new species, the thorax exhibits darker lateral vittae at the anterior end and gradually becomes lighter toward the posterior end; the dorsal half of MA II is dark brown, and there is a distinct dark brown spot between AA II and Pp. Regarding the legs, the anterior femur is predominantly pale, with a slightly darker tone at the distal end, while the anterior tibia and tarsus are dark brown. In the thorax of Z. fasciata, the lateral vittae are darker at the posterior end, and laterally, there is only a small brown spot on the pleural region. The legs of Z. fasciata are uniformly light brown. According to Sublette (1964), the thorax of Z. smithae displays a reddish-brown coloration on the vittae, postnotum, and preepisternum. In addition, the new species has abdominal TI mostly pale, with only anterolateral brown spots; TII has a continuous brown band anteriorly, and TV has narrow, faint lateral stripes. In contrast, in Z. fasciata, TII has a discontinuous band on the posterior margin and in Z. smithae, TI is mostly brown, with a pale white dorsal disc, and TV has a narrow posterior band. According to Roback (1971), Z. anomala has abdominal tergites 1, 3, 4, 6, and 8 with a broad basal band, whereas tergites 2, 5, and 7 are pale—a pattern that differs significantly from that observed in the new species. Zavrelimyia ximenesae sp. nov. has two preapical pits on the gonostylus, each bearing a small seta. This feature has not been mentioned in the descriptions of other species of the genus, suggesting its potential as a diagnostic character for the new species. However, it is possible that this structure is present in other species but has been overlooked in previous descriptions.
According to Roback (1972) and Sublette & Sasa (1994), the pupae of Z. smithae and of Z. fasciata have spines on the inner margin of the anal lobe. This feature is currently considered diagnostic of the subgenus Z. (Zavrelimyia), distinguishing Z. fasciata and Z. smithae not only from Z. ximenesae sp. nov., but also from all other known pupae of Zavrelimyia (Paramerina). In contrast, the males of Z. (P.) fasciata and Z. (P.) smithae lack setae on TIX, and the phallapodeme is notably long and curved anteriorly, characteristics that are diagnostic of the subgenus Zavrelimyia (Paramerina). This observed divergence in the morphology of different stages of Z. fasciata and Z. smithae, compared to the current definition of the Zavrelimyia subgenera, suggests that the ‘diagnostic characteristics’ used to define these subgenera may need to be revised, clarified, and supplemented with new data. This also underscores the need for a comprehensive taxonomic and phylogenetic revision to clarify species relationships within Zavrelimyia.
description: Published as part of Dantas, Galileu P. S., Pinheiro, Marcos P. G. & Hamada, Neusa, 2025, The first species of Zavrelimyia Fittkau, 1962 (Diptera: Chironomidae) described from South America, pp. 192-200 in Zootaxa 5632 (1) on pages 193-199, DOI: 10.11646/zootaxa.5632.1.12, http://zenodo.org/record/15371458