Cyclocephala tucumana Bréthes, 1904

Fuhrmann, Juares, Dias, Bruno Mateus Ribeiro & Rodrigues, Sérgio Roberto, 2019, Population dynamics and description of larva and pupa of Cyclocephala tucumana Bréthes, 1904 in West-Central Brazil, and remarks on immatures of other Cyclocephala species (Coleoptera: Scarabaeidae: Dynastinae), Revista Brasileira de Entomologia 63 (4), pp. 331-342 : 332-337

Cyclocephala tucumana Bréthes, 1904

Third-instar larva ( Figs. 3, 4 , 7–44 ). Body ( Fig. 3 ) length 17.41 mm (12.4–23.0), cranium width 3.3 mm (2.1 − 4.4), thorax width 4.96 mm (3.3–6.0); yellowish white, head and respiratory plates yellow; surface setose, setae yellowish brown. Head ( Figs. 4 , 7 , setation in Table 1). Epicranial and epistomal sutures distinct; stemmata absent; antennifer somewhat cylindrical and with 4–7 punctures; cranium, clypeus, and labrum ( Figs. 7, 8 ) with homogeneously distributed punctures, except in the anterior area of labrum. Each half of cranium and clypeus with ( Fig. 7 ): 4–5 long and 0–2 minute dorsoepicranial setae (des), 4–6 long and 0–2 minute posteroepicranial setae (pes), 1–2 long anteroepicranial setae (aes), 5–9 long externoepicranial setae (ees), 2 long and 0–1 minute posterofrontal setae (pfs), 1 externofrontal seta (efs), 2–3 long anterofrontal angle setae (aas), 2 long anterofrontal setae (afs), 2 long externoclypeal setae (ecs), 1 long anteroclypeal seta (acs). Each half of labrum ( Fig. 8 ) with 2–3 long posterolabral setae (pls), 1 long mediolabral seta (mls), 4 long laterolabral setae (lls), and 2–3 long anterolabral setae (als). Antenna ( Figs. 9–12 ) with 4 antennomeres: I with 7 sensilla (1 dorsal, 1 outer, 5 ventral); II with 9 sensilla (3 dorsal, 6 ventral); III with 5 sensilla (2 dorsal, 3 ventral), ventrodistal process bearing a dorsal sensorial spot and 3 distal sensilla; IV with 7 sensilla (1 inner, 4 outer, 2 ventral), 2 dorsal and 2 ventral sensorial spots, and a distal sensorial area bearing about

9 prominent minute sensilla. Epipharynx ( Figs. 13, 14 ). Corypha : epizygum distinct and clithra absent. Haptomerum: zygum beaklike, 2-toothed and with about 3 sensilla; heli absent. Paria : acroparia evidently separated from chaetoparia and right side with about 20 setae, left side with about 12 setae; each side of acanthoparia with 12 anterior setae and 1–4 minute posterior setae; gymnoparia narrow; right chaetoparia with 57–63 setae and 36–46 sensilla, left chaetoparia with 49–57 setae and 17–22 sensilla; dexiotorma slightly longer than laeotorma, left pterotorma rounded, apotorma indistinct, epitorma as an impressed rounded sulcus; plegmatia slightly distinct at middle or almost indistinct, proplegmatia and phoba absent. Pedium longer than wide and smooth. Haptolachus with right area bearing 6 setae and 2 sensilla and left area bearing 8 setae and 2 sensilla; nesium internum (sensorial cone) as a superficial plate, entire or divided at middle and with 4 sensilla; nesium externum (sclerotized plate) prominent and acute; crepis lateral area conspicuous and medial area almost indistinct. Mandible ( Figs.15–20 ). Incisor with 2 well-defined teeth (S2 inconspicuous), dorsoproximal area with 1 puncture. Ventral striated stridulatory area with about 19 thin anterior striae and 6 broad posterior striae. Ventral area with 3–4 medial punctures and posterior asperites. Scrobe (outer proximal area) with about 5 setae. Ventral processes well developed. Both molars with about 9 dorsoproximal setae in a row, 5–7 ventroproximal setae in a tuft, and brustia with 4–6 setae; right molar with 3 chisel-like teeth and calx slightly sinuous; left molar with 1 anterior chisel-like tooth, 2 dorsal and 1 ventral teeth, acia with truncate apex and bearing about 5 setae, calx semicircular. Maxilla ( Figs. 21–23 ). Galea and lacinia fused (as a mala) and limited from each other by dorsal suture; galea with an uncus; lacinia with 3 unci; mala without conspicuous setae row. Stipe with stridulatory area bearing 9–10 obtuse teeth and a distal truncate tooth. Palp with 4 palpomeres: I with a dorsoproximal sensillum; II with an outer dorsal sensillum and 3–4 ventral sensilla; III with an outer seta, a ventral seta and 2 ventral sensilla; IV with or without an outer sensillum, distal sensorial area bearing about 13 sensilla. Hypopharynx ( Figs. 14 , 22 ) with asymmetrical sclerite, right lateral of sclerite with about 5 punctures, left lateral with about 7–8 long setae, lateromedial left area with a row of 21–25 stout setae; right anterior area with a prominent tooth. Posterior preoral area: each side of dorsal area (posterior to epipharynx, Fig. 13 ) with a sensillum; each side of ventral area (posterior to hypopharynx, Fig. 22 ) with 1–2 sensilla, left area with a row of 18–21 stout setae. Labium ( Figs. 14 , 22, 23 ). Submentum with an inconspicuous sclerite, each side with 2 setae and about 9 sensilla. Mentum with a transversal sclerite, each side with 1 seta and 3–6 sensilla. Prementum with a transversal sclerite, each side with about 7 setae distributed around palpus insertion; ligula ( Figs. 14 , 22 ) with 33–36 small stout setae, a small medial tubercle and a posterior transversal sclerite, right area with 11–13 long setae, left area with 17–23 long setae, posterior area bearing asperites. Palp with 2 palpomeres: I with a minute ventroproximal seta; II with a ventrodistal sensillum, distal sensory area with about 13 sensilla. Thorax ( Fig.3 , setation in Table 2). Prothorax with a tergal lobe bearing 6–8 minute anterior setae, 8–10 short or long posterior setae, and 6 lateral setae; thoracic lateral sclerite with 4–6 setae; pleural anterior lobe with 2–3 setae, pleural posterior lobe with 10 setae, ventral anteromedial lobe with 36–40 setae, and ventral posterior lobe bare. Meso- and metathorax with tergal anterior lobe bearing 6–8 setae, tergal medial lobe with 31–40 setae, tergal posterior lobe bare, pleural anterior lobe with 2–3 setae, pleural posterior lobe with 3–9 setae, ventral anteromedial lobe with 23–24 setae, and ventral posterior lobe bare. Legs ( Figs.24–26 ). Pro-, meso- and metafemur with 2 small inner tubercles, each tubercle bearing 2 distal setae; pretarsus ( Figs. 27–29 ) with 2 lateroventral setae and an acuminate apex, propretarsus as long as meso- and longer than metapretarsus. Thoracic spiracle ( Figs. 30, 31 , see remarks) with 14–17 perforations in dorsal and ventral radius (DR, VR) and 13–15 in longitudinal radius (LR); perforations oblong; bulla slightly wider than the distance between respiratory plate arms. Abdomen ( Fig. 5 , setation in Table 2). Segment I with tergal anterior lobe bearing 8–12 thin and 0–2 stout setae, tergal medial lobe with 16–20 thin and 8–18 stout setae, tergal posterior lobe with 8–11 thin and 16–17 stout setae, pleural anterior lobe bare, pleural posterior lobe with 3–9 setae, spiracle lobe with 0–2 setae, tergal lateral lobe indistinct or distinct and bearing 0–2 setae, ventral anterior lobe with 6–16 setae, ventral medial lobe with 2 setae, ventral posterior lobe bare. Segment II with tergal anterior lobe bearing 6–10 thin and 23–28 stout setae, tergal medial lobe with 21–26 thin and 68–80 stout setae, tergal posterior lobe with 5–8 thin and 43–63 stout setae, pleural lobes and tergal lateral lobe as segment I, spiracle lobe with 4–9 setae, ventral lobes as segment I. Segments III–V with tergal anterior lobe bearing 2–6 thin and 38–50 stout setae, tergal lateral lobe with 2–4 setae, other lobes as segment II. Segment VI with tergal anterior lobe bearing 2–4 thin and 53–63 stout setae, tergal medial lobe with 25–28 thin and 55–64 stout setae, tergal posterior lobe with 12–16 thin and 24–33 stout setae, ventral anterior lobe with 4–8 setae, other lobes as segments III–V. Segment VII with tergal anterior lobe bearing 10–25 thin and 0–6 stout setae, tergal medial lobe indistinct, tergal posterior lobe with 14–28 thin setae, tergal lateral lobe indistinct, ventral anterior lobe with 2–4 setae, other lobes as segment VI. Segment VIII with a tergal lobe bearing 25–28 thin setae, ventral lobe with 4 setae, dorsolateral lobes as segment VII. Segment IX with a tergal lobe bearing 10–15 anterior setae and 21–24 posterior setae, pleural lobe with 9–11 setae and ventral lobe with 4 setae. Tergite X ( Fig. 44 ) with a curved anal opening and an anterior U-shaped thin sclerotized bar, sclerite delimiting an anterior thin area and a wide posteromedial area, each side of anterior area with 5–7 dorsolateral setae and 7–11 lateral setae, posteromedial area with about 130 anterior thin setae and about 40 posterior stout setae. Spiracles ( Figs. 33, 35–37, 39–42 , see remarks): I–VI smaller than VII–VIII, respiratory plates with 9–12 perforations in DR and VR, and 6–9 in LR; bulla slightly wider than the distances between respiratory plate arms. Raster ( Figs. 43–44 , setation in Table 1). Each side of tegillar area with 15–22 hamate setae, each side of campus with 1–2 setae, palidia and septula restricted to anal ventral lobe, consequently all tegillar area is preseptular (i.e., anterior to septula), barbula indistinct. Anal ventral lobe, each palidium with 6–7 stout pali, each palus associated with a small transverse sclerome, septula somewhat oval, each side with 8–10 hamate lateral setae.

Material examined. Brazil, Mato Grosso do Sul, Cassilândia, Chácara Buritizinho , 04.viii.2016, leg. Bruno M. R . Dias, 8 third-instar larvae and 1 third-instar cast skin ( MZSP – 10364).

Remarks. Cyclocephala larvae are known for 22 species (descriptions given in brackets): C. barrerai ( Morón et al., 2014) , C. borealis ( Johnson, 1941; Ritcher, 1944, 1966), C. celata ( Souza et al., 2014b) , C. comata ( García et al., 2009) , C. distincta ( Souza et al., 2014a) , C. fasciolata ( Morón et al., 2014) , C. flavipennis ( Pereira and Salvadori, 2006) , C. fulgurata ( Bran et al., 2006) , C. gregaria ( Bran et al., 2006) , C. jalapensis ( Morón et al., 2014) , C. longula (= C. abrupta ; Ritcher, 1944, 1966), C. lunulata ( Bran et al., 2006; King, 1984; Morón et al., 2014; Stechauner-Rohrínger and Pardo-Locarno, 2010), C. lurida (= C. immaculata ; Ritcher, 1944, 1966), C. melanocephala ( Rodrigues et al., 2018) , C. modesta (raster figured in Morelli, 1991), C. paraguayensis ( Albuquerque et al., 2014) , C. pasadanae ( Ritcher, 1944, 1966), C. putrida (raster figured in Morelli, 1991), C. signaticollis ( Morelli, 1991; Remedi-de-Gavotto, 1964), C. sinaloae ( Morón et al., 2014) , C. testacea ( Morelli and Alzugaray, 1994) , C. tucumana (present study).

Regarding the above-mentioned species, only C. melanocephala , C. modesta , C. paraguayensis , C. testacea and C. tucumana have palidia. Palidia of C. testacea are long (each palidium with more than 30 pali) and abruptly divergent posteriorly; the other four species have short palidia (each palidium with less than 10 pali) and they are slightly divergent only in C. modesta . Cyclocephala paraguayensis and C. melanocephala are easily separate from others by the bifurcate pali (see Rodrigues et al. 2018: Fig. 44a ). Finally, C. modesta and C. tucumana have palidia present on ventral anal lobe and pali are simply acuminate. Palidia of C. tucumana are restricted to anal lobe and palidia of C. modesta are extended anteriorly to raster.

The chaetotaxy of head, raster, and anal lobe ( Table 1) is useful as supplement to larvae identification key below. Rodrigues et al. (2018) described the chaetotaxy for thoracic and abdominal lobes of C. melanocephala and highlighted the entire body setation as a possible identification tool. In the present study, body setation is also quantified, and the comparison between C. melanocephala and C. tucumana showed several setal group differences, mainly between setae of tergal lobes ( Tables 2 and 3).

Eight larvae and a cast skin were here studied. Usually the spiracles have their bulla slightly wider than the distance between respiratory plate arms ( Figs. 31, 33, 35–37, 39–42 ), but one of studied larvae has spiracles with bulla narrower than the distance between respiratory plate arms ( Figs. 32, 34, 38 ). This variation was not noticed to other Cyclocephalini larvae.

Figures

Figs.1–6. Cyclocephala tucumana; 1, adult male, dorsal;2, external genitalia of adult female,ventrolateral;3–4, third-instarlarva;3, lateral;4, head,frontal;5–6, terminalia of female pupa,ventral (normal genital ampulla,teratological genital ampulla).fgl–fgr, left and right lobes of female genital ampulla; gcx, left gonocoxite;ggl, left gonangulum; gst, left gonostyle; ppt, left paraproct (barely distinct). Scale, Figs. 1, 3, 5 =1 mm; Figs. 2, 4 = 0.5mm (Photos by Rafael Sousa, MZSP).

Figs. 7–12. Cyclocephala tucumana, third-instar larva; 7, cranium and clypeus, dorsal; 8, labrum, dorsal (epipharyngeal ventral setae omitted); 9–12, left antenna (dorsal, inner, outer, ventral; dorsal side with apex detail; some sensilla numbered to easily the correspondence). Chaetotaxy (italic) on the text. Scale =0.5 mm (antennal details with magnification four times bigger than antennae).

Figs. 13–14. Cyclocephala tucumana, third-instar larva; 13, epipharynx; 14, cibarium, lateral. aca, anterior-most acanthoparia seta; acr, lateroposterior acroparia seta; crp, right part of crepis; lip, tubercle-like process of ligula; ppa, posterior preoral area. Scale= 0.5mm.

Figs. 15–20. Cyclocephala tucumana, third instar larva;15–17, right mandible (ventral, inner, dorsal); left mandible (dorsal, inner, ventral).S1–3, distal, medial, and proximal teeth of incisor (pointed line showing inconspicuous or barely distinct tooth), inn, incisor notch (between S2 and S3). Scale =0.5 mm.

Figs. 21–23. Cyclocephala tucumana, third-instar larva; 21, right maxilla, inner (cardo omitted); 22, maxilla, hypopharynx and ligula, dorsal; 23, maxilla and labium, ventral. ppa, posterior preoral area. Scale =0.5 mm (palp details with magnification four times bigger than the maxillolabial complex).

Figs. 24–42. Cyclocephala tucumana, third-instar larva; 24–26, left legs and pleurites (anterior, medial, posterior); 27–29, right pro-, meso-, and metapretarsus, dorsal; 30, detail of ventral arm of mesothoracic spiracle; 31–32, mesothoracic spiracle; 33–34, abdominal spiracle I; 35–36, abdominal spiracle II and III; 37–38, abdominal spiracle IV; 39–42, abdominal spiracles V–VIII. Scale, Fig. 24 = 0.5mm; Figs. 27, 30, 31 =0.1mm.

Figs. 43–44. Cyclocephala tucumana, third-instar larva; 43, raster, ventral; 44, abdominal segment X, posterior.Scale =1 mm.