Castolus rafaeli, Forero & Mejía-Soto, 2021

Forero, Dimitri & Mejía-Soto, Andrés, 2021, A striking sexually dimorphic new species of Castolus (Hemiptera: Heteroptera Reduviidae) from Colombia, with new records from Neotropical countries and taxonomic notes on the genus, Zootaxa 5048 (4), pp. 538-560 : 541-548

Castolus rafaeli sp. nov.

( Figs. 1–5 )

Diagnosis. Castolus rafaeli sp. nov. is easily recognized from all the known species of Castolus by its contrasting black and orange or red coloration, being sexually dimorphic, in which males have a black body with red thorax ( Figs. 1A, B ), whereas females have a mostly black body with red areas on the head, anterior pronotal lobe, posterior margin of posterior pronotal lobe, and abdomen ( Figs. 2A, B ); by having both sexes the postantennal spines long and erect ( Fig. 1C ); and the humeral spines long ( Fig. 1D ).

Description. Male. Average measurements, range within parentheses, n=2 (first measurement is of holotype): Total length 14.88 mm (15.07–14.68); head length: 2.55 mm (2.51–2.60); head width: 1.57 mm (1.60–1.53); pronotal length: 2.86 mm (2.88–2.84); pronotal width: 3.39 mm (3.38–3.39). COLORATION: Overall coloration black with red areas ( Fig. 1A, B ). Head: Black, collum red. Thorax: Red; pronotum red, humeral spines black; scutellum red ( Fig. 1D ). Legs: Black, coxae red with an apicodorsal black area. Hemelytron: Shiny black, membrane dark. Abdomen: Black; sternite II ventrally and up to below spiracle red, sternite III on anteromedial portion red; pygophore black. VESTITURE: Hemelytron with sparse, very delicate, semi-decumbent setae. STRUCTURE: Elongated body. Head: Anteocular and postocular regions about the same length ( Fig. 1D ); eye hemispherical, protruding laterally in dorsal view, not reaching dorsal or ventral margin in lateral view ( Fig. 1C ); ocellus protruding, raised on postocular region, ocellus closer to eye than to other ocellus; postantennal spine thick, erect, long, almost as long as eye height ( Fig. 1C ); scape as long as basiflagellomere, pedicel and distiflagellomere about the same length, nearly a third of scape length, basiflagellomere slightly wider on basal third ( Fig. 1D ); first (visible) labial segment reaching posterior margin of eye, second and third segment as long as first, third less than half of second ( Fig. 1C ). Thorax: Anterior angle of pronotum blunt; anterior pronotal lobe rounded, shorter than second, surface polished, longitudinal sulcus on posterior area deeply marked; posterior pronotal lobe trapezoidal, disc slightly elevated, humeral spines long, directed laterad ( Fig. 1D ); scutellum with disc elevated, slightly medially depressed, apex with a blunt spine directed caudad; mesepisternum flat, without tubercles. Hemelytron: Membrane surpassing apex of abdomen ( Fig. 1A ). Genitalia: Pygophore ovoid ( Fig. 1E ); process of the genital opening (pgo) broadly produced dorsally, beset with long, dense setae on its posterior margin ( Fig. 1E ); posterior margin of pygophore deeply emarginated medially, with paired setose areas, located close to the paramere socket (ps) ( Fig. 1F ), setose areas (sa) placed on slightly elevated cuticle; median process of the pygophore (mpp) sigmoid in lateral view ( Fig. 1E ), uniform in width in caudal view ( Fig. 1F ), apex blunt; paramere long, almost reaching median process of pygophore, nearly cylindrical, with long, dense setae on dorsal surface of apex ( Figs. 1E, F ); aedeagus with basal plate arms wide, slightly sinuous, close to each other, basal plate bridge very narrow and nearly membranous; dorsal phallothecal sclerite (dps) ovoid ( Fig. 1G ), nearly flat in lateral view ( Fig. 1I ); struts reaching about midpoint of dps, nearly parallel on basal half, divergent on apical half; endosoma with medial basal sclerotization (mbs) as a pair of short, longitudinal, slightly corrugated sclerites ( Fig. 1G ); medial dorsal lobe (mdl) with a posterior, dorsally projected, strongly sclerotized Vshaped portion, beset with triangular microtrichia, anterior portion a pair of rounded, poorly sclerotized areas, with more sclerotized, strongly recurved margin beset with longer microtrichia ( Fig. 1G ); distal dorsal lobe (ddl) beset with very small microtrichia; distal ventral lobe (dvl) with a pair of narrow sclerites ( Fig. 1H ).

Female: Stouter, similar to male except as follows. Average measurements, range within parentheses: Total length: 17.37 mm (16.37–18.51; n=5); head length: 2.57 mm (2.36–2.68; n=5); head width: 1.60 mm (1.48–1.64; n=4); pronotal length: 2.86 mm (2.48–3.02; n=5); pronotal width: 3.84 mm (3.35–4.08; n=5). COLORATION: Overall coloration bright red with black markings ( Figs. 2A, B ). Head: Red; labrum and anterior portion of clypeus black; antenna black, flagellomeres paler than scape and pedicel; area between antennal tubercles black, sometimes black coloration extending anteriorly reaching the clypeus; postantennal spine black; postocular region adjacent to ocelli black; second and third (visible) labial segments black ( Fig. 2B ). Thorax: Anterior pronotal lobe red, anterior angle black; posterior pronotal lobe including humeral spines black, posterior margin with a broad red area, with three prolongations extending anteriad, one at base of each humeral spine, and one medial, lateral ones longer than medial one, length and width on these anteriad red markings variable, from almost not extending anteriad ( Fig. 2C , 3B ) to strongly extending anteriad nearly reaching anterior lobe of pronotum ( Fig. 3A ); scutellum red; pleura red, procoxal lobes black connecting to black area of posterior pronotal lobe, meso- and metacoxal lobes with a smaller black area, mesepisternum on area dorsal to mesocoxal lobe with a small black area ( Fig. 2B ). Legs: Black, coxae red with an apicodorsal black area; mid and hind femur with narrow pale ring on middle of segment, inconspicuous dorsally, rarely visible dorsally. Hemelytron: shiny black, membrane dark. Abdomen: Red; tergites darkened; lateral areas on sternites III–VII, between each segment, with irregular ovoid dark areas, sometimes anterior lateral area of segment III with a smaller ovoid black area ( Fig. 2B ); posterior lateral area of segment VII with a small dark area; gonocoxa 8 medially darkened; gonapophysis 8 darkened apically; syntergite 9/10 darkened apically. STRUCTURE: Head: Eye slightly reniform ( Fig. 2B ); basiflagellomere of uniform diameter. Genitalia: Gonocoxa 8 (gcx8) with posterior margin slightly concave; gonapophysis 8 (gap8) narrow, apically with numerous, stout, short setae ( Fig. 2F ); gonocoxa and gonapophysis 9 not examined; gonoplac (gpl) not medially fused, apically rounded; syntergite 9/10 quadrangular, proximal half with a round, strongly convex area, with small anterior portion concave, distal half with narrow transversely depressed area, distal portion strongly convex; bursa copulatrix subrectangular, membranous (Fig, 2D), area of insertion of median oviduct (mo) in bursa completely membranous ( Fig. 2E ); subrectal glands present, nearly as long as bursa ( Fig. 2D ).

Nymphs: 1st instar ( Fig. 4B ): pale yellow without dark markings. 3rd instar ( Fig. 4C ): dark yellow; antenna dark, distiflagellomere yellow; wing pads dark; abdominal mediotergites with a longitudinal red line reaching mid length of abdomen; head ovoid, postantennal spine not conspicuous; anterior lobe of pronotum ovoid, shiny, strongly convex; abdomen large and ovoid. 4th instar ( Fig. 4D ): similar to 3rd instar, darker, postantennal spines small, blunt. 5th instar: orange-red with black markings; seemly dimorphic; female ( Fig. 4E ) with apex of clypeus black; second and third (visible) labial segments black; postantennal spine and adjacent area black; ocellar area black; postocular portion of head laterally black; antenna black with flagellomeres paler; pronotum with anterolateral angle black, large lateral, smaller medial, and posterior markings black; wing pads black, legs black; abdominal mediotergites 7–8 with a medial black area, segment 9 black; male ( Fig. 4F ) similar to female, but with less dark markings on head ant thorax; mid and hind femur with medial, narrow pale ring; both sexes with long and erect postantennal spine ( Figs. 4E, F ).

Material examined. HOLOTYPE: COLOMBIA — Antioquia • 1 ♂; El Retiro, finca la Pilarica; 06.07118°N 75.496831°W; 2100 m; 30 ene 2018; A. Mejía leg.; criado de huevos [bred from egg batch] / CEUA 109653 / (red label) Holotype Castolus rafaeli sp. nov. Forero & Mejía-Soto ( CEUA) .

PARATYPES: COLOMBIA — Antioquia • 1 ♀; El Carmen de Viboral, v[ere]da Camargo ; [06.0720°N, 75.3409°W]; 2150–2200 m; May 2010; K. Quintero leg.; [colecta] manual; CEUA 99058 ( CEUA) • 1 ♀; same data; 22 May 2010; J. Garcia leg.; CEUA 99059 ( CEUA) • 1 ♀; Girardota, vda [vereda] Juan Cojo ; [06.3504°N, 75.4574°W]; 1600–1700 m; 22–26 ago 2009; bosque; CEUA 99128 ( CEUA) • 1 ♂; El Retiro, finca la Pilarica ; 06.07118°N, 75.496831°W; 2100 m; 30 ene 2018; A. Mejía leg.; criado de huevos [reared from eggs]; [genitalia dissected]; MPUJ _ ENT00064056 ( MPUJ _ ENT) • 1 ♂; same data; 11 Jul 2018; reared from eggs; MPUJ _ ENT0068465 ( MPUJ _ ENT) • 1 ♂; same data; 28 Jul 2018; reared from eggs; MPUJ _ ENT0068466 ( MPUJ _ ENT) • 1 ♀; same data; 8 May 2018; reared from eggs; MPUJ _ ENT0068467 ( MPUJ _ ENT) • 1 ♀; same data; 3 Feb 2018; breeding female; MPUJ _ ENT0068468 ( MPUJ _ ENT) • 1 ♀; Guarne, vereda La Honda ; [06.2261°N, 75.4587°W]; 1250 m; 13 Abr 2014; Edison Toro S. leg.; 237 [abdomen dissected] ( MEFLG) • 1 ♀; San Vicente, v[ere]da Chaparral ; 6°15’49”N, 75°21’40”W; 2100–2200 m; 11 Dic 2015; A. Mejía leg.; [en] domicilio, [colecta] manual; CEUA 99110 ( CEUA) .

OTHER EXAMINED MATERIAL: COLOMBIA — Antioquia • 6 nymphs, 1st instar; El Retiro, finca la Pilarica; 06.07118°N, 75.496831°W; 2100 m; 11 Mar 2018; A. Mejia leg.; criados de huevos [reared from egg batch]; in ETOH; CEUA 109646 ( CEUA) • 4 nymphs, 2nd instar; same data; 30 Mar 2018; in ETOH; CEUA 109647 ( CEUA) • 4 nymphs, 3rd instar; same data; 20 Apr 2018; in ETOH; CEUA 109648 ( CEUA) • 3 nymphs, 4th instar; same data; 15 May 2018; in ETOH; CEUA 109649 ( CEUA) • 5 nymphs, 5th instar; same data; 2 Jun 2018; in ETOH; CEUA 109650 ( CEUA) .

(iNaturalist observations): COLOMBIA — Antioquia • 1 nymph; Envigado ; 06.1181°N, 75.5814°W; 29 Jan 2014; A. Ortega leg; https://www.inaturalist.org/observations/66622640 • 1 ♀; Carrera 43C, Cl. 4 Sur #199, Medellín ; 06.1995442°N, 75.5765974°W; 28 Jan 2017; David Foster leg.; https://www.inaturalist.org/observations/20262656 • 1 ♀; El Carmen de Viboral ; 06.051249°N, 75.326458°W; 2300 m; 8 Dic 2019; Á. M. Gómez leg.; https://www. inaturalist.org/observations/36488939 • 1 ♂; El Carmen de Viboral ; 06.051249°N, 75.326458°W; 2300 m; https:// www.inaturalist.org/observations/36513106 • 1 ♀; [near El Carmen de Viboral ]; 6.0573°N 75.3709°W; 2300 m; 30 Apr 2019; Á. M. Gómez leg.; seen walking around the house, among the house plants, roofs, grass, frequent in the garden, [preying on a Muscidae ]; https://www.inaturalist.org/observations/36488934 • 1 ♀; [near El Carmen de Viboral ]; 06.0607°N, 75.3023°W; 29 Sep 2019; Á. M. Gómez leg.; seen walking around the house, among the house plants, roofs, grass, frequent in the garden; https://www.inaturalist.org/observations/36488930 • 1 ♂; [near El Carmen de Viboral ]; 06.0399°N, 75.3224°W; 2300 m; 17 Oct 2019; Á. M. Gómez leg.; relatively frequent near the house and surroundings; https://www.inaturalist.org/observations/36513101 • 1 ♀; Guarne , 06.295493°N, 75.472604°W; 23 Jun 2019; S. Serna leg.; https://www.inaturalist.org/observations/27601988 • 1 ♂; Guarne ; 06.29563°N, 75.47256°W; 1 Jan 2020; S. Serna leg.; https://www.inaturalist.org/observations/37217235 • 1 ♀; [Hacienda] Fizebad , [near embalse La Fe]; 06.09581°N, 75.51282°W; 14 Ago 2020; V. Aboultaif leg.; https://www. inaturalist.org/observations/56446616 • 1 ♀; Peñol ; 06.21996°N, 75.24353°W; 23 Dic 2018; V. Mercier leg.; https:// www.inaturalist.org/observations/27835514 • 1 ♂; Retiro ; 06.05890°N, 75.49937°W; 15 May 2020; S. Múnera leg.; https://www.inaturalist.org/observations/46021041 • 1 ♂; Retiro ; 06.09734°N, 75.50804°W; D. Foster leg.; https://www.inaturalist.org/observations/36544670 • 1 ♀; Rionegro ; 06.18338°N, 75.46163°W; 9 Jan 2020; S. Jisi leg.; https://www.inaturalist.org/observations/42307121 — Santander • 1 ♀; Bolívar ; 06.146553°N, 73.81020°W; 14 Feb 2020; U. Camargo leg.; https://www.inaturalist.org/observations/39544078 • 1 ♀; Bolívar ; 06.14642°N, 73.81005°W; 13 Feb 2020; U. Camargo leg.; https://www.inaturalist.org/observations/39544102 . PANAMA — Coclé • 1 ♀; el Valle [de Anton ]; 08.621605°N, 80.1394312°W; 2 Sep 2012; E. R. Nielsen leg.; https://www.inaturalist. org/observations/18126830 .

Distribution. Colombia and probably also Panama. Examined specimens from entomological collections are all from northern Colombia, from localities on the Central Cordillera in Antioquia, especially on eastern areas between 2,000 –2,250 m ( Fig. 5A , circles). Observations from iNaturalist ( Fig. 5A , inverted triangles) are also from these areas in Antioquia, with an additional locality in Santander on the Eastern Cordillera. Additionally, an examined image from iNaturalist of this new species is from central Panama ( Fig. 5A , inverted triangle). Future studies should corroborate with specimens the presence of C. rafaeli sp. nov. in Panama.

Biology. Most of the observed specimens in the field were found in low vegetation or close to houses in the countryside during the day. The observations from iNaturalist are congruent with our field observations and show that both sexes can be found in these circumstances. In some cases, specimens were observed hunting Muscidae flies, as well as other Brachycera, but from the iNaturalist images examined it is certain that other prey can be consumed as well. The female kept in the rearing chamber laid 5 eggs masses ( Fig.4A ), hatching between 30–35 nymphs from each. The first oviposition was on February 5th, 2018, and after 30 to 31 days the nymphs emerged. The last oviposition was on April 7th, 2018. The average time between each oviposition was 10–24 days, and it took 29–31 day to hatch all the eggs. After hatching, it took between 22–35 days to molt into II instar, from II to III instar 22–28 days, from III to IV instar 23–27 days, from IV to V between 23–26 days, and finally from V to adult 14–25 days for males and 34–40 days for females. Nevertheless, very few individuals were able to reach the adult stage; e.g., in one egg mass, only 9 out of 35 specimens reached the adult stage, where 8 were males and 1 a female. The female which oviposited the egg masses remained alive for 3 months after capture as an adult, but the longevity must be much longer. It must be noted that these observations were based on different egg masses from a single female, which does not allow generalization of developmental times for the species.

Etymology. The new species is named after the senior author’s son, Rafael Forero, in celebration of his life and the possibility to help him accomplish his dreams. Rafael likes to paint and enjoys using vibrant colors, and thus, we are sure he will be thrilled having such a striking-colored true bug named after him.

Discussion. Maldonado (1976) provided a redescription of Castolus , indicating the most relevant external characters that characterize this genus. Castolus is nonetheless a challenging taxon to diagnose, as evidenced by the molecular phylogenetic analysis of Zhang & Weirauch (2014), in which most terminals assigned to Castolus fall into a single clade, with a few terminals identified as “cf. Castolus ” found outside this clade. At least some of the terminals in their analysis identified as such might be in fact other taxa, e.g., UCR_ENT 00005122 (“cf. Castolus 2280 ”), which is a good Repipta species based on its external morphology. Swanson and Chordas (2018) highlighted the most important attributes that might allow recognition of the genus, including the mesopleuron without a tubercle (= “plica” of authors), the first visible labial segment longer than the second, the lack of spines on the posterior margin the posterior pronotal lobe, femora apically without spines, and hemelytra not wider than pronotal width. Both Maldonado (1976) and Swanson and Chordas (2018) also discussed the value of the male genitalia in helping recognize Castolus . In general, species of Castolus have a non-bifid median process of the pygophore, and a pair of setose areas on the posterior margin of the pygophore adjacent to the median process. Nonetheless, some characters are variable within the genus, such as the armature of the humeral angles, ranging from completely rounded (e.g., C. plagiaticollis ) to strongly spined (e.g., C. lineatus ), or the structure of the anterior pronotal lobe, which is barely convex in some species or large and inflated in others (e.g., C. trinotatus ). Maldonado (1976) stated that species of Castolus have very short postantennal spines, and some species even lack them, although might have short ones (e.g., C. subinermis ). Thus, having a new species with a well-developed postantennal spine and marked sexual dimorphism, fits well with the present delimitation of Castolus ( Maldonado 1976; Swanson & Chordas 2018).

Castolus rafaeli sp. nov. superficially resembles a few other Harpactorini species from South America due to its contrasting black and red coloration. Females of the new species externally resembles females of Zelus chamaeleon Stål, 1872 ( Zhang et al. 2016a) (https://bit.ly/3lyptjw, https://bit.ly/3lwsIYJ) because of its mostly dark dorsal coloration with red areas on the head, pronotum, and abdominal sternites. Castolus rafaeli sp. nov. can easily be distinguished from Z. chamaeleon because of the presence of a large, erect, postantennal spine, which is completely lacking in Z. chamaeleon , and because the anterior lobe of the pronotum in Z. chamaeleon is always black whereas in C. rafaeli sp. nov. is always red. Another striking similar species is Repipta fuscipes (Stål, 1855) , which has a nearly identical coloration ( Martin-Park et al. 2012), particularly to females of C. rafaeli sp. nov. The new species can be separated from R. fuscipes because of the lack of paired posteriad medial spines on the posterior lobe of the pronotum, a character shared by all known species of Repipta , and by the large and erect postantennal spines, which in R. fuscipes are mere small tubercles. It is unknown if these species are part of a mimetic complex, but at least C. rafaeli sp. nov. and Z. chamaeleon might be sympatric because both can be found in Antioquia.

The male of C. rafaeli sp. nov. was unknown among the specimens examined, until rearing egg masses from a female showed that the male exhibited a completely different coloration pattern ( Figs. 1A , 2A ). The striking different coloration between sexes might have hindered their association as a single species if not reared from the same egg batch. This extreme sexual dimorphism is not found in other species of Castolus , where only minor differences in the color pattern are found (e.g., C. lineatus ). Sexually dimorphic species are rare in Harpactorini, but there are a few Neotropical species with such attribute. In Corcia columbica Stål, 1859 , males and females have constant but completely different color patterns each (see female: https://bit.ly/350Xt0u; male: https://bit.ly/3w4PKKB). In two species of Zelus , Z. laticornis (Herrich-Schaeffer, 1853) and Z. versicolor (Herrich-Schaeffer, 1848) , there is also marked sexual dimorphism ( Gil-Santana 2008; Zhang et al. 2016a). It is still unknown the biological reason for a sexually dimorphic color pattern among these species of Harpactorinae. Color pattern is the main character used to separate species within Castolus ( Brailovsky 1982; Maldonado 1976; Swanson & Chordas 2018), therefore, understanding the variability of color patterns in different taxa is important to help recognize the limits for species in Castolus .

Figures

FIGURE 1. Castolus rafaeli sp. nov., male holotype (CEUA 109653). A. Dorsal view; B. lateral view; C. detail of head in lateral view; D. detail of head and thorax in dorsal view; E. lateral view of pygophore; F. posterior view of pygophore; G–I. inflated aedeagus, G. dorsal view; H. ventral view; I. lateral view. Abbreviations: ddl, distal dorsal lobe; dps, dorsal phallothecal sclerite; dvl, distal ventral lobe; mbs, medial basal sclerotization of endosoma; mdl, medial dorsal lobe of endosoma; mpp, median process of pygophore; pgo, process of the genital opening; ps, paramere socket; sa, setose areas of posterior margin of pygophore.

FIGURE 2. Castolus rafaeli sp. nov., female paratype (CEUA 99059). A. Dorsal view; B. lateral view; C. detail of head and thorax in dorsal view; D. genitalia, ventral view, showing bursa copulatrix and subrectal glands; E. detail of insertion of median oviduct on bursa copulatrix; F. detail of gonocoxa 8, gonapophysis 8, and gonoplac.Abbreviations: gap8, gonapophysis 8; gcx8, gonocoxa 8; gpl, gonoplac; mo, median oviduct.

FIGURE 3. Live female specimens of Castolus rafaeli sp. nov. showing pronotal color variability. A. Panama (photo E. R. Nielsen); B. Colombia, Antioquia.

FIGURE 4. Castolus rafaeli sp. nov., A–E. eggs and nymphs reared from a single female (El Retiro, Antioquia), F. from an iNaturalist observation. A. Egg mass; B. First instar nymphs; C. third instar; D. fourth instar; E. fifth instar female nymph; F. fifth instar male nymph.

FIGURE 5. Distribution map of Castolus species based on data from examined specimens and iNaturalist observations. A. C. rafaeli sp. nov.; B. C. lineatus.