taxonID	type	description	language	source
86168792B524FF9AFE44763D841AD08A.taxon	description	urn: lsid: zoobank. org: act: 42112360 - 0489 - 4016 - AE 9 B-D 77716 E 84 C 70 Figs 1 D, 2 – 7, 15 C	en	Serafim, Ingrid R., Santos, Júlio C. C. V., Ferreira, Rodrigo L. (2026): Ghosts of subterranean waters: two new troglobitic species of Spelaeometra D. Polhemus & Ferreira, 2018 (Heteroptera: Hydrometridae) from Brazil, with remarks on the enigmatic species Cephalometra pallida D. Polhemus & Ferreira, 2018. European Journal of Taxonomy 1077: 1-28, DOI: 10.5852/ejt.2026.1077.3306, URL: https://europeanjournaloftaxonomy.eu/index.php/ejt/article/download/3306/14546
86168792B524FF9AFE44763D841AD08A.taxon	diagnosis	Diagnosis Spelaeometra ybykoara sp. nov. can be distinguished from all other species of the genus by the following combination of characters: antennae not exceeding body length, compound eyes with 16 ommatidia; and parameres tripartite, with well-developed subtriangular apical process ventrad, almost reaching the middle of the distal arm.	en	Serafim, Ingrid R., Santos, Júlio C. C. V., Ferreira, Rodrigo L. (2026): Ghosts of subterranean waters: two new troglobitic species of Spelaeometra D. Polhemus & Ferreira, 2018 (Heteroptera: Hydrometridae) from Brazil, with remarks on the enigmatic species Cephalometra pallida D. Polhemus & Ferreira, 2018. European Journal of Taxonomy 1077: 1-28, DOI: 10.5852/ejt.2026.1077.3306, URL: https://europeanjournaloftaxonomy.eu/index.php/ejt/article/download/3306/14546
86168792B524FF9AFE44763D841AD08A.taxon	etymology	Etymology The specific epithet is a noun in apposition derived from the Tupi word yby-koara, meaning “ cave inhabitant. ” This term originates from the Tupi language, spoken by indigenous peoples of Brazil, and is used here to honor the region’s cultural heritage and its deep connection to the land. As a noun in apposition, the epithet is indeclinable and does not change to agree in gender with the genus name.	en	Serafim, Ingrid R., Santos, Júlio C. C. V., Ferreira, Rodrigo L. (2026): Ghosts of subterranean waters: two new troglobitic species of Spelaeometra D. Polhemus & Ferreira, 2018 (Heteroptera: Hydrometridae) from Brazil, with remarks on the enigmatic species Cephalometra pallida D. Polhemus & Ferreira, 2018. European Journal of Taxonomy 1077: 1-28, DOI: 10.5852/ejt.2026.1077.3306, URL: https://europeanjournaloftaxonomy.eu/index.php/ejt/article/download/3306/14546
86168792B524FF9AFE44763D841AD08A.taxon	materials_examined	Type material Holotype BRAZIL • ♂; Bahia state, Carinhanha municipality, Lapa dos Peixes I cave; 13 ° 50 ′ 16.750 ″ S, 43 ° 58 ′ 29.060 ″ W; 4 Jun. 2024; Ferreira R. L. leg.; preserved; ISLA 126339. Paratypes BRAZIL • 1 ♂; same collection data as for holotype; dissected; ISLA 126340 • 2 ♀♀; same collection data as for holotype; ISLA 126342 – 43 • 2 juvs; same collection data as for holotype; ISLA 126345 • 1 ♂, 2 ♀♀; same collection data as for holotype; 17 Jul. 2024; ISLA 126346 – 48 • 2 ♀♀; same collection data as for holotype; 7 May 2023; ISLA 126349 – 50.	en	Serafim, Ingrid R., Santos, Júlio C. C. V., Ferreira, Rodrigo L. (2026): Ghosts of subterranean waters: two new troglobitic species of Spelaeometra D. Polhemus & Ferreira, 2018 (Heteroptera: Hydrometridae) from Brazil, with remarks on the enigmatic species Cephalometra pallida D. Polhemus & Ferreira, 2018. European Journal of Taxonomy 1077: 1-28, DOI: 10.5852/ejt.2026.1077.3306, URL: https://europeanjournaloftaxonomy.eu/index.php/ejt/article/download/3306/14546
86168792B524FF9AFE44763D841AD08A.taxon	description	Description Male apterous BODY LENGTH. 2.48 – 2.60 mm (n = 3; including one small, one medium, and one large specimen), maximum width (at abdomen) 1.19 – 1.26 mm (n = 3). Structural characters holotype HEAD. Length 0.77, width 0.26; length interocular 0.25, transocular 0.33, ocular width 0.06, ocular length 0.09; eyes with 16 ommatidia present. Antennal segments I – IV = 0.27, 0.24, 0.93, 1.09. Rostrum length 1.67, lip segment length I – IV = 0.10, 0.06, 1.11, 0.40, respectively. THORAX. Length 0.43, width 0.47, with only the pronotum visible, covering the mesonotum and metanotum. LEGS. Segment lengths: anterior femur, tibia, tarsus I, tarsus II, tarsus III = 0.74, 0.88, 0.04, 0.16, 0.11; middle femur, tibia, tarsus I, tarsus II, tarsus III = 0.83, 1.04, 0.03, 0.19, 0.10; posterior femur, tibia, tarsus I, tarsus II, tarsus III = 1.12, 1.67, 0.03, 0.3, 0.12. ABDOMEN. Length 1.23, maximum width 0.68, minimum width 0.48. Length of abdominal tergites I – VII = 0.14, 0.17, 0.15, 0.19, 0.18, 0.19, 0.19; maximum width of abdominal tergites I – VII = 0.41, 0.37, 0.32, 0.31, 0.29, 0.27, 0.22. (Table 1). General description (paratype, ♂, ISLA 126340) COLORATION (preserved specimen) (Figs 2 A – C, 3 A – C). head and thorax, brilliant orange-yellow (67, sRGB Centroids for ISCC-NBS Level 3 Categories), basally on the thorax and apically on the abdomen, strong orange-brownish (68). Appendage insertions light yellow (86), bringing dark to moderate yellow (87) along their length. Abdomen and male genitalia strong yellowish-brown (74). HEAD. In dorsal view (Fig. 3 A), lateral margin slightly concave, carinae behind the eyes totally elevated. In lateral view (Fig. 3 C), dorsal margin convex, ventral margin sinuous with two small convexities and two small concavities. In ventral view (Fig. 3 B), longitudinal carinae weakly elevated. Rostrum (Fig. 2 B), long and slender, surpassing the third abdominal segment. Cephalic trichobothria (Figs 3 A, C, 4 F) present, as described for the genus. Compound eyes (Fig. 4 C – D) reduced, bearing 16 ommatidia with ocular setae present; ocelli absent. Antennae (Fig. 2 A – C), not exceeding body length; antennal segments as described for the genus. THORAX. In dorsal view (Fig. 3 A) with pronotum slightly bilobed laterally, almost linear distally. Wings (Fig. 3 A) completely absent, with interior wing buds visible. In lateral view (Fig. 3 C), thoracic pleurae as described for the genus. In ventral view (Fig. 3 B), sternum bearing paired, sinuous, slightly raised longitudinal carinae. ABDOMEN. In dorsal view, mediotergites almost equal in length (Fig. 4 A, G). Scent orifice on mediotergite IV obscure (Fig. 4, g 1). In ventral view, some regions brownish. LEGS (Fig. 2 A – C). Anterior and posterior legs with few distinct setae. Femur slender proximally. Tibiae long and robust (Fig. 2 A – C). Tarsi as in other species of the genus, except for tarsus II: long on the anterior and middle legs, short on the hind leg. Middle leg with one claw on tarsus III (Fig. 5 A), fore and hind legs with two claws on the apex of tarsus III (Fig. 5 B). MALE GENITALIA (Fig. 6 A – F). Parameres, bilaterally symmetrical, relatively large and broad, tripartite, with a short basal stem, distal arm with concave dorsal margin, convex ventral margin, with well-developed subtriangular apical process ventrad, almost reaching the middle of the distal arm. Female apterous BODY LENGTH. 2.53 – 2.68 (n = 3; including one small, one medium, and one large specimen), maximum width (at abdomen) 1.30 – 1.32 (n = 3). Structural characters as in males, elongated.	en	Serafim, Ingrid R., Santos, Júlio C. C. V., Ferreira, Rodrigo L. (2026): Ghosts of subterranean waters: two new troglobitic species of Spelaeometra D. Polhemus & Ferreira, 2018 (Heteroptera: Hydrometridae) from Brazil, with remarks on the enigmatic species Cephalometra pallida D. Polhemus & Ferreira, 2018. European Journal of Taxonomy 1077: 1-28, DOI: 10.5852/ejt.2026.1077.3306, URL: https://europeanjournaloftaxonomy.eu/index.php/ejt/article/download/3306/14546
86168792B524FF9AFE44763D841AD08A.taxon	biology_ecology	Habitat and threats Spelaeometra ybykoara sp. nov. is currently known only from a single locality within the Água Clara Cave System (ACCS), a complex linear network of four major subterranean conduits formed in calcarenitic strata of the Sete Lagoas Formation, which forms striking carbonate outcrops in the region. From upstream to downstream, these caves include Gruna da Água Clara (13 880 m), Gruna dos Índios (510 m), Lapa dos Peixes I (9320 m; Figs 6 A – C. 13 A, E), and Lapa dos Peixes II (2100 m). The species was recorded exclusively in Lapa dos Peixes I, a cave characterized by a pronounced seasonal microclimatic gradient created by airflow between entrances located at opposite ends of the conduit. While much of the main gallery becomes markedly dry during the austral winter, the section where specimens were collected retains consistently high humidity throughout the year due to the presence of a perennial water body. This microhabitat, notable for its environmental stability, hosts the highest richness of troglobitic species in the ACCS (Souza-Silva & Ferreira 2016; Ferreira & Souza-Silva 2023). Despite extensive biological inventories across all caves of the system, Spelaeometra ybykoara sp. nov. (Fig. 7 D – E) has not been found outside this discrete habitat, strongly suggesting a highly restricted distribution and microendemism. The species’ apparent confinement to a single, permanently humid conduit section underscores its potential vulnerability to environmental fluctuations and anthropogenic disturbance. The broader ACCS is subject to severe external pressures, particularly from agricultural expansion and wood harvesting for charcoal production in the surrounding region (Fig. 7 B; Ferreira et al. 2023; Ferreira & Souza-Silva 2023). Extensive deforestation near cave entrances (Fig. 8 A – B) has reduced organic input, simplified habitat structure, and increased soil erosion. These changes accelerate the transport of fine sediments into the cave system, leading to substrate homogenization and the degradation of aquatic and terrestrial microhabitats, processes that disproportionately threaten highly specialized hypogean fauna (Pellegrini et al. 2016; Cardoso et al. 2022). Given the exceptional biodiversity of the ACCS, including numerous troglobitic taxa, and the apparent micro-endemism of S. ybykoara sp. nov., conservation measures are urgently required. We recommend the establishment of a legally protected conservation unit that encompasses not only the subterranean system but also its contributing catchment microbasins and the surrounding karst landscape. Such a designation, supported by strict environmental regulations, would be essential to safeguard the ecological integrity of this unique subterranean ecosystem and ensure the long-term survival of its highly specialized fauna.	en	Serafim, Ingrid R., Santos, Júlio C. C. V., Ferreira, Rodrigo L. (2026): Ghosts of subterranean waters: two new troglobitic species of Spelaeometra D. Polhemus & Ferreira, 2018 (Heteroptera: Hydrometridae) from Brazil, with remarks on the enigmatic species Cephalometra pallida D. Polhemus & Ferreira, 2018. European Journal of Taxonomy 1077: 1-28, DOI: 10.5852/ejt.2026.1077.3306, URL: https://europeanjournaloftaxonomy.eu/index.php/ejt/article/download/3306/14546
86168792B52AFF84FDAB729F86D3D167.taxon	description	urn: lsid: zoobank. org: act: FCC 0 E 40 E-C 5 FE- 4 A 77 - 86 DB-F 71 DFA 5 A 0720 Figs 9 – 12, 15 D	en	Serafim, Ingrid R., Santos, Júlio C. C. V., Ferreira, Rodrigo L. (2026): Ghosts of subterranean waters: two new troglobitic species of Spelaeometra D. Polhemus & Ferreira, 2018 (Heteroptera: Hydrometridae) from Brazil, with remarks on the enigmatic species Cephalometra pallida D. Polhemus & Ferreira, 2018. European Journal of Taxonomy 1077: 1-28, DOI: 10.5852/ejt.2026.1077.3306, URL: https://europeanjournaloftaxonomy.eu/index.php/ejt/article/download/3306/14546
86168792B52AFF84FDAB729F86D3D167.taxon	diagnosis	Diagnosis Spelaeometra iuiu sp. nov. can be distinguished from all other species of the genus by the following combination of characters: compound eyes bearing 10 – 12 ommatidia; paramere tripartite, large and wide, with a strongly angled ventrolateral margin, and with a short ventroapical hook, not exceeding ⅓ of the length of the anterior region.	en	Serafim, Ingrid R., Santos, Júlio C. C. V., Ferreira, Rodrigo L. (2026): Ghosts of subterranean waters: two new troglobitic species of Spelaeometra D. Polhemus & Ferreira, 2018 (Heteroptera: Hydrometridae) from Brazil, with remarks on the enigmatic species Cephalometra pallida D. Polhemus & Ferreira, 2018. European Journal of Taxonomy 1077: 1-28, DOI: 10.5852/ejt.2026.1077.3306, URL: https://europeanjournaloftaxonomy.eu/index.php/ejt/article/download/3306/14546
86168792B52AFF84FDAB729F86D3D167.taxon	etymology	Etymology The specific epithet iuiu is a noun in apposition, referring to the municipality of Iuiú, Bahia State, Brazil, where the species was collected. As a noun in apposition, the epithet is indeclinable and does not change to agree in gender with the genus name.	en	Serafim, Ingrid R., Santos, Júlio C. C. V., Ferreira, Rodrigo L. (2026): Ghosts of subterranean waters: two new troglobitic species of Spelaeometra D. Polhemus & Ferreira, 2018 (Heteroptera: Hydrometridae) from Brazil, with remarks on the enigmatic species Cephalometra pallida D. Polhemus & Ferreira, 2018. European Journal of Taxonomy 1077: 1-28, DOI: 10.5852/ejt.2026.1077.3306, URL: https://europeanjournaloftaxonomy.eu/index.php/ejt/article/download/3306/14546
86168792B52AFF84FDAB729F86D3D167.taxon	materials_examined	Type material Holotype BRAZIL • ♂; Bahia State, Iuiú municipality, Toca Fria cave; 14 ° 32 ′ 52.861 ″ S, 43 ° 32 ′ 8.992 ″ W; 12 Sep. 2023; Ferreira R. L. leg.; preserved; ISLA 125922.	en	Serafim, Ingrid R., Santos, Júlio C. C. V., Ferreira, Rodrigo L. (2026): Ghosts of subterranean waters: two new troglobitic species of Spelaeometra D. Polhemus & Ferreira, 2018 (Heteroptera: Hydrometridae) from Brazil, with remarks on the enigmatic species Cephalometra pallida D. Polhemus & Ferreira, 2018. European Journal of Taxonomy 1077: 1-28, DOI: 10.5852/ejt.2026.1077.3306, URL: https://europeanjournaloftaxonomy.eu/index.php/ejt/article/download/3306/14546
86168792B52AFF84FDAB729F86D3D167.taxon	description	Description Male apterous BODY LENGTH. (n = 1) 2.39, maximum width (at abdomen) 1.19 mm. Structural characters HEAD. Length 0.69, width 0.24; length interocular 0.21, transocular 0.29, ocular width 0.04, ocular length 0.06; eyes with 10 – 12 ommatidia present; Antennal segments I – IV = 0.24, 0.24, 0.74, 1.30. Rostrum length 1.54, lip segment length I – IV = 0.10, 0.05, 1.07, 0.32, respectively. THORAX. Length 0.40, width 0.47, with only the pronotum visible, covering the mesonotum and metanotum. LEGS. Segment lengths: anterior femur, tibia, tarsus I, tarsus II, tarsus III = 0.67, 0.91, 0.02, 0.18, 0.09; middle femur, tibia, tarsus I, tarsus II, tarsus III = 0.85, 1.03, 0.03, 0.18, 0.09; posterior femur, tibia, tarsus I, tarsus II, tarsus III = 1.04, 1.54, 0.04, 0.28, 0.11. ABDOMEN. Length 1.19, maximum width 0.55, minimum width 0.48. Length of abdominal tergites I – VII, respectively = 0.17, 0.11, 0.17, 0.18, 0.16, 0.19, 0.18; maximum width of abdominal tergites I – VII = 0.35, 0.33, 0.31, 0.28, 0.25, 0.21, 0.17. (Table 1) General description COLORATION (preserved specimen; Fig. 9 A – C). head, thorax, and abdomen strong orange yellow (68, sRGB Centroids for ISCC-NBS Level 3 Categories), basally on the thorax and apically on the abdomen, deep orange yellow (69). Appendage insertions light orange yellow (70), changing to moderate orange yellow (71) along their length. HEAD. In dorsal view (Fig. 10 A), lateral margin slightly concave, carinae behind the eyes totally elevated. In lateral view (Fig. 10 C), dorsal margin convex, ventral margin straight. In ventral view (Fig. 10 B), longitudinal carinae weakly elevated. Rostrum (Figs 9 B – C, 10 B), long and slender, surpassing the third abdominal segment. Cephalic trichobothria (Fig. 10 A, C) present, as described for the genus. Compound eyes (Fig. 10 A – C) reduced, bearing 10 – 12 ommatidia without ocular setae; ocelli absent. Antennae (Fig. 9 A – C), longer than body length; antennal segments as described for the genus, except segments I and II of equal size. THORAX. In dorsal view (Fig. 10 A), with pronotum slightly bilobed laterally, almost linear distally. Wings (Fig. 10 A) completely absent, with interior wing buds visible. In lateral view (Fig. 10 C), thoracic pleurae as described for the genus. In ventral view (Fig. 10 B), with sternum bearing paired, sinuous, slightly raised longitudinal carinae. ABDOMEN. In dorsal view, mediotergites almost equal in length (Fig. 9 A). Scent orifice not visible on mediotergite IV. LEGS (Fig. 9 A – C). Anterior and posterior legs with few distinct setae. Femur slender proximally. Tibiae long and robust (Fig. 9 A – C). Tarsi, like other species of the genus, with approximately the same size. Middle leg with one claw on tarsus III, fore and hind legs with two claws on the apex of tarsus III as in Spelaeometra ybykoara sp. nov. MALE GENITALIA (Fig. 11 A – F). Parameres bilaterally symmetrical, relatively large and long, tripartite, with a short basal stem; distal arm with dorsal margin slightly concave at the end of the joints; ventral margin slightly convex; subtriangular apical process developed ventrally, not reaching the middle of the distal arm.	en	Serafim, Ingrid R., Santos, Júlio C. C. V., Ferreira, Rodrigo L. (2026): Ghosts of subterranean waters: two new troglobitic species of Spelaeometra D. Polhemus & Ferreira, 2018 (Heteroptera: Hydrometridae) from Brazil, with remarks on the enigmatic species Cephalometra pallida D. Polhemus & Ferreira, 2018. European Journal of Taxonomy 1077: 1-28, DOI: 10.5852/ejt.2026.1077.3306, URL: https://europeanjournaloftaxonomy.eu/index.php/ejt/article/download/3306/14546
86168792B52AFF84FDAB729F86D3D167.taxon	biology_ecology	Habitat and threats Spelaeometra iuiu sp. nov. is currently known only from Toca Fria Cave, located in the municipality of Iuiú, southwestern Bahia State, Brazil (Fig. 12 A – C). Although this is the only confirmed locality, the presence of several other caves in the same limestone outcrop suggests that additional populations may eventually be found in nearby systems. However, it is important to note that numerous caves in the main massif of the Serra de Iuiú karst have been surveyed, and no specimens were found in these systems, suggesting that this species may be restricted to the Serrinha outcrop. The Serrinha outcrop (Fig. 12 A), which hosts Toca Fria Cave, is a relatively small karst formation measuring approximately 2.4 km in length and 1.3 km in width. It lies about 4 km in a straight line from the main massif of the Serra de Iuiú. Toca Fria is a labyrinthine cave system extending roughly 2500 m, with multiple entrances concentrated along the outcrop margins. Permanent water bodies are absent from most of the cave; however, during the rainy season, several conduits become flooded, and moisture persists for several months following rainfall events. By the end of the dry season, the cave’s substrates are predominantly desiccated (Fig. 12 C), with residual moisture restricted to sheltered microhabitats beneath rocks in a few interior areas. Spelaeometra iuiu sp. nov. (Fig. 12 D – E) was found under a rock in this moist, secluded area, well beyond the reach of natural light near the entrances. Several conduits also contained partially moistened sediments resulting from surface runoff infiltrating through the entrances. The pronounced seasonal drying of the cave suggests that individuals may retreat to deeper, permanently humid zones inaccessible to humans during the dry season, reappearing in the macrocavern during wetter periods. Although Toca Fria Cave is occasionally visited by residents, its irregular topography and narrow passages limit visitation primarily to the vicinity of the main entrance, leaving deeper sectors relatively undisturbed. In contrast, the external environment is heavily altered. Most of the native vegetation surrounding the outcrop has been replaced by pasture, except for areas along its upper portion, where patches of xerophytic vegetation persist. Extensive tracts of bare soil now encircle the outcrop (Fig. 12 A), promoting soil erosion and sediment deposition within the cave during periods of intense rainfall. Such landscape alterations likely diminish organic matter input and disrupt critical subterranean microhabitats, posing a significant threat to the long-term survival of this species.	en	Serafim, Ingrid R., Santos, Júlio C. C. V., Ferreira, Rodrigo L. (2026): Ghosts of subterranean waters: two new troglobitic species of Spelaeometra D. Polhemus & Ferreira, 2018 (Heteroptera: Hydrometridae) from Brazil, with remarks on the enigmatic species Cephalometra pallida D. Polhemus & Ferreira, 2018. European Journal of Taxonomy 1077: 1-28, DOI: 10.5852/ejt.2026.1077.3306, URL: https://europeanjournaloftaxonomy.eu/index.php/ejt/article/download/3306/14546
86168792B534FF84FE43732484BDD541.taxon	description	Figs 1 F, 13	en	Serafim, Ingrid R., Santos, Júlio C. C. V., Ferreira, Rodrigo L. (2026): Ghosts of subterranean waters: two new troglobitic species of Spelaeometra D. Polhemus & Ferreira, 2018 (Heteroptera: Hydrometridae) from Brazil, with remarks on the enigmatic species Cephalometra pallida D. Polhemus & Ferreira, 2018. European Journal of Taxonomy 1077: 1-28, DOI: 10.5852/ejt.2026.1077.3306, URL: https://europeanjournaloftaxonomy.eu/index.php/ejt/article/download/3306/14546
86168792B534FF84FE43732484BDD541.taxon	materials_examined	Type material Holotype BRAZIL • ♂ apterous; Minas Gerais, Itacarambi, Lapa D’Água do Zezé; 25 Jan. 2015; Ferreira R. L. leg.; ISLA 10042. Paratypes BRAZIL • 2 ♂♂, 5 ♀♀; same data as for holotype; ISLA, BPBM • 2 ♀♀; Minas Gerais, Itacarambi, Cavernas do Peruaçu National Park, Gruta Caboclo; 13 Dec. 2014; Ferreira R. L. leg.; ISLA 10042; ISLA • 2 ♂♂, 2 ♀♀; Minas Gerais, Itacarambi, Gruta do Nestor; 25 Jan. 2015; Ferreira R. L. leg.; ISLA 10042; ISLA • 1 ♀; Minas Gerais, Montalvânia, Gruta do Fóssil; 14 ° 21 ′ 37 ″ S, 44 ° 18 ′ 55 ″ W; 13 Apr. 2016; Ferreira R. L. leg.; ISLA 15681; ISLA • 1 immature; same data as for preceding; ISLA 15680; ISLA • 4 ♂♂, 3 ♀♀, 1 immature; Minas Gerais, Montalvânia, Lapa Grande; 26 Nov. 2016; Ferreira et al. leg.; ISLA 46653; ISLA • 1 ♂; Minas Gerais, Montalvânia, Gruta do Fóssil; 28 Nov. 2016; Ferreira et al. leg.; ISLA 46654; ISLA. Other material examined BRAZIL • 2 ♂♂; Minas Gerais, Itacarambi Montalvânia, Gruta do Fóssil; 14 ° 21 ′ 37 ″ S, 44 ° 18 ′ 55 ″ W; 13 Apr. 2016; Ferreira R. L. leg.; ISLA 157015 • 1 ♂; ISLA 157016 (Fig. 13).	en	Serafim, Ingrid R., Santos, Júlio C. C. V., Ferreira, Rodrigo L. (2026): Ghosts of subterranean waters: two new troglobitic species of Spelaeometra D. Polhemus & Ferreira, 2018 (Heteroptera: Hydrometridae) from Brazil, with remarks on the enigmatic species Cephalometra pallida D. Polhemus & Ferreira, 2018. European Journal of Taxonomy 1077: 1-28, DOI: 10.5852/ejt.2026.1077.3306, URL: https://europeanjournaloftaxonomy.eu/index.php/ejt/article/download/3306/14546
86168792B534FF84FE43732484BDD541.taxon	discussion	Remarks Spelaeometra gruta D. Polhemus & Ferreira, 2018 (Fig. 13 A – D) was the first species described within the genus Spelaeometra and represents the first hydrometrid lineage known to exhibit an exclusively cave-dwelling habit. Similar to its congeners, this species possesses an odoriferous orifice located on the fourth mediotergite of the abdomen (Fig. 13 D, d 1). Spelaeometra gruta is relatively widespread in limestone caves situated in the municipalities of Itacarambi, Montalvânia and Juvenília, in northern Minas Gerais State.	en	Serafim, Ingrid R., Santos, Júlio C. C. V., Ferreira, Rodrigo L. (2026): Ghosts of subterranean waters: two new troglobitic species of Spelaeometra D. Polhemus & Ferreira, 2018 (Heteroptera: Hydrometridae) from Brazil, with remarks on the enigmatic species Cephalometra pallida D. Polhemus & Ferreira, 2018. European Journal of Taxonomy 1077: 1-28, DOI: 10.5852/ejt.2026.1077.3306, URL: https://europeanjournaloftaxonomy.eu/index.php/ejt/article/download/3306/14546
86168792B533FF81FE4C711D8759D631.taxon	description	Fig. 14	en	Serafim, Ingrid R., Santos, Júlio C. C. V., Ferreira, Rodrigo L. (2026): Ghosts of subterranean waters: two new troglobitic species of Spelaeometra D. Polhemus & Ferreira, 2018 (Heteroptera: Hydrometridae) from Brazil, with remarks on the enigmatic species Cephalometra pallida D. Polhemus & Ferreira, 2018. European Journal of Taxonomy 1077: 1-28, DOI: 10.5852/ejt.2026.1077.3306, URL: https://europeanjournaloftaxonomy.eu/index.php/ejt/article/download/3306/14546
86168792B533FF81FE4C711D8759D631.taxon	discussion	Remarks Cephalometra pallida is evidently a rare and elusive species. It is known exclusively from Natividade cave, and despite extensive sampling efforts in other caves throughout the region, it has never been recorded outside this locality (Fig. 14 A – B). Moreover, the population appears to be restricted to a single chamber situated in the innermost portion of the cave, which is connected to the phreatic zone. The holotype was collected on 15 May 2005, and subsequent surveys failed to detect additional adults for many years (Fig. 14 D). Only a single immature specimen was found on 5 May 2013. No individuals were observed on 8 January 2016, and 24 February 2018, only immature specimens were recorded (Fig. 14 C). Finally, on 9 June 2025 (after approximately 20 years), adult individuals were detected again. Given the sporadic nature of these surveys, it is currently not possible to formulate any robust hypotheses regarding the species’ life cycle. However, considering that the chamber in which the species is observed is relatively small, it is plausible that individuals may migrate to other subterranean compartments during certain periods of the year, possibly in search of more suitable microhabitats. As mentioned in the original description of Cephalometra pallida, human-induced alterations are clear in the outermost portions of the cave, particularly near the main entrance. Historical accounts from residents indicate that saltpeter extraction for gunpowder production occurred there until at least the 1940 s. This activity has left visible traces, including excavated depressions and patches of burned material in the entrance zone and the first chamber. In contrast, the deeper sections of the cave, where C. pallida specimens are observed, show no indications of past human presence. These inner compartments appear to have remained untouched, suggesting that historical visitors did not venture beyond the accessible entrance areas. As a result, the deeper environment has been preserved in a largely pristine state. In contrast, the external habitats surrounding it have undergone significant alteration in recent years, primarily due to forest clearing for pastures and agriculture. Although degraded areas were already evident during our first visit in 2005, the extent of deforestation has increased markedly since then. This trend raises concerns regarding the long-term conservation of the species, as deforestation can lead to sedimentation processes that modify subterranean habitats and reduce the influx of organic matter into the cave, both factors capable of compromising the species’ viability over time. Given these threats, systematic monitoring of the population is strongly recommended. Additionally, the creation of a protected area encompassing the limestone outcrop that hosts the cave, together with reforestation of the surrounding landscape, would provide essential safeguards to ensure the persistence of this highly vulnerable species.	en	Serafim, Ingrid R., Santos, Júlio C. C. V., Ferreira, Rodrigo L. (2026): Ghosts of subterranean waters: two new troglobitic species of Spelaeometra D. Polhemus & Ferreira, 2018 (Heteroptera: Hydrometridae) from Brazil, with remarks on the enigmatic species Cephalometra pallida D. Polhemus & Ferreira, 2018. European Journal of Taxonomy 1077: 1-28, DOI: 10.5852/ejt.2026.1077.3306, URL: https://europeanjournaloftaxonomy.eu/index.php/ejt/article/download/3306/14546
