Description of immature stages of Meroscelisus zikani Melzer, 1919 (Cerambycidae, Prioninae, Meroscelisini)ABSTRACT
The Neotropical genus Meroscelisus Audinet-Serville is distributed throughout southern South America and currently comprises six species. Among these is Meroscelisus zikani Melzer, a species previously known only from a few records in Minas Gerais state, Brazil. Herein, we describe the larva and pupa of M. zikani based on specimens and exuviae collected from a single decayed wood in Campos do Jordão, São Paulo state. Although this represents the first record for São Paulo, it confirms the species' occurrence within the ombrophilous forests of the Serra da Mantiqueira mountain range. We provide photographs and illustrations of the morphological features and compare them with known immatures of other Meroscelisini. The larva of M. zikani is similar to other South American Meroscelisini in its epistomal shape but can be distinguished by the absence of stemmata. M. zikani pupa is unique in having segment IX smooth, without microspines, and head largely exposed, while in the other known pupae the segment IX has microspines and the head is almost totally covered by prothorax.
Keywords:
Microplophorus; Mixed Ombrophilous Forest; Nectandra; Polyoza; Quercivir
1. Introduction
The tribe Meroscelisini currently comprises 13 genera and 45 species from South America, Africa and Europe (Tavakilian and Chevillotte, 2026). Up to date, five Meroscelisini species have their larvae described: Microplophorus magellanicus Blanchard, 1851 (Duffy, 1960; Cekalovic, 1970); Polyoza lacordairei Audinet-Serville, 1832 (Heller, 1904; Casari and Nascimento, 2019); Tragosoma harrisii LeConte, 1851 (Craighead, 1915); Trichoderes pini Chevrolat, 1843 (Candèze, 1861), and Quercivir gounellei Lameere, 1912 (Casari and Nascimento, 2019). Pupae are known only for M. magellanicus (Cekalovic 1970), P. lacordairei and Q. gounellei (Casari and Nascimento, 2019).
Meroscelisus Audinet-Serville, 1832 is a Neotropical genus distributed in southern South America, in Brazil, Paraguay, and Argentina. The genus is the type-genus of the Meroscelisini and is currently composed of six species, among which is Meroscelisus zikani Melzer, 1919, known only from a few records in Minas Gerais state, Brazil (Galileo, 1987).
Although immature morphology has long been recognized as a valuable source of characters for cerambycid systematics, it remains poorly known, and higher-level classifications continue to rely predominantly on adult morphology (Švácha and Lawrence, 2014; Casari et al., 2025). Consequently, the description of additional immature stages is essential to expand the comparative morphological framework and provide characters for future phylogenetic and taxonomic revisions of Cerambycidae (Casari and Nascimento, 2019; Casari et al., 2025).
Herein, we describe the larva and pupa of M. zikani, the first immature description for the genus and compare them with the previously described meroscelisine immatures. The specimens were collected in the municipality of Campos do Jordão, state of São Paulo, Brazil, the first record for this state.
2. Material and Methods
Collecting, immature-adult association, and material depository. One mature larva, one pupa and larval and pupal exuviae still attached to the teneral female were collected in a decayed wood in a legal reserve in Campos do Jordão municipality, São Paulo state (Fig. 1). The association of the mature larva and pupa was inferred from morphological comparison of the whole specimens (larva and pupa) with the exuviae found with the female. Larva and pupa were killed in boiling water and preserved with the exuviae in alcohol 70%; the female was reared until completing the final sclerotization and then killed in alcohol cooled to -18oC and pinned. Identification was made by comparison to the type specimens (Fig. 2) deposited at Museu de Zoologia de São Paulo (MZSP). Morphological study was conducted at Universidade Federal de Itajubá (UNIFEI) and the material deposited at MZSP.
Collecting site and alive semaphoronts of Meroscelisus zikani Melzer, 1919. A, collecting site in Campos do Jordão municipality, São Paulo state; B, decayed wood where specimens were found; C, female pupa; D, teneral female removed from its chamber and larval and pupal exuviae still inside the chamber.
Meroscelisus zikani Melzer, 1919. Adult: A-B, male lectotype (MZSP 34367) habitus (dorsal, ventral); C, male lectotype head, frontal view; D, female paralectotype (MZSP 34371) habitus (dorsal); E-F, female associated with immatures (dorsal, ventral). Bars = 1 mm
Morphological study. We dissected larvae and exuviae in water and mounted the pieces in Hoyer’s medium. Drawings were made with a camera lucida adapted to a stereomicroscope Zeiss Discovery V8 and from photographs taken through the eyepiece of a microscope. Photographs of the male (lectotype) and female (paralectotype) were taken in the MZSP, respectively, with a Canon EOS Rebel T3i DSLR camera, Canon MP-E 65mm f/2.8 1–5X macro lens, controlled by Zerene Stacker AutoMontage software and with Zeiss Axio Cam MRc5 camera mounted on a Zeiss Discovery V12 stereomicroscope and Zeiss ZEN Pro 2011 software The remaining photos were taken at the Laboratory of Zoology of UNIFEI with a Canon EOS Rebel T6 camera coupled to Canon EF 100 mm f/2.8. The stacked images were obtained with Helicon Focus 4.03; figure plates were edited on Adobe Photoshop 24.2.1 software. We follow the terminology in Švácha and Lawrence (2014) and Casari and Nascimento (2019).
3. Results
Descriptions
Meroscelisus zikani Melzer, 1919
Larva (Figs. 3-5). Length: 46 mm.
Meroscelisus zikani Melzer, 1919. Larva: A-B, Head and thorax (dorsolateral, ventrolateral).
Meroscelisus zikani Melzer, 1919. Larva: A-B, mandible (internal and external views); C-D, antenna (dorsal, apex dorsal); E, epistoma, clypeus, labrum and antenna; F, epipharynx; G, maxillolabial complex (ventral); H, leg (prothoracic). Bars = 1 mm, except C, H = 0.5 mm, D = 0.01 mm.
Body (Figs. 3, 4) subcylindrical, thorax slightly flatter dorsoventrally; integument soft, pale yellow (darkened after preservation), smooth and translucent. Head capsule pale yellow, except anterior borders (mouth frame) dark brown; clypeus pale yellow, labrum and mouthparts pale yellow to light brown, except mandibles dark brown; antennae pale yellow and light brown. Legs pale yellow. Thorax and abdomen with more or less retractile ambulatory ampullae. Pubescence erect, light brown, sparse, and of varied sizes, denser on prothorax.
Meroscelisus zikani Melzer, 1919. Larva: A-B, Apex of abdomen (dorsolateral, ventrolateral).
Head (Figs. 3, 5E , G) capsule moderately convex, deeply retracted into prothorax, 1.06 times as wide as long, widest on posterior third; posterior margin notched at middle forming two rounded lobes. Median frontal line (endocarina) long, almost reaching epistomal margin; frontal arms short, not reaching median frontal line. Epistomal margin (Fig. 5E) declivous to anteclypeal base, upper boundary sinuous and carinate laterally near condylar area (frontal carina), lower boundary almost straight (weakly arched); each side with three setae; postcondylar area convex. Frons near epistomal margin with one pair of parasagittal setae; each side with a transverse row of 4 setae, several smaller and long setae near pleurostoma, and several sparse, short setae anterodorsally. Stemmata absent. Tentorial cross-arm (tentorial bridge) dividing foramen into an anterior and a posterior portion; hypostomal line elongate, almost reaching foramen; gula and postgular lobe very short, transverse. Antennae (Figs. 5C, D) short, extensible, with antennifer membranous and two elongate antennomeres; basal antennomere glabrous, with several pores with internal channel on apical half; distal antennomere apically with one elliptical, flat sensorium, 3–4 campaniform sensilla and six setae (two minuscule and four longer). Clypeus (anteclypeus) (Fig. 5E) about 3 times wider than long, trapezoidal, membranous. Labrum (Fig. 5E) convex, semielliptical, 2.1 times wider than long, constricted at base, distal third membranous, densely covered with stiff brown setae; basal region more sclerotized, median third with few setae and pores with internal channel. Epipharynx (Fig. 5F) borders densely covered with setae directed to middle; basal region narrow with shorter setae and median pores; one sclerite on each side on basal half (tormae). Mandibles (Figs. 5A , B) about 1.1 times longer than wide, strongly sclerotized, apical and subapical teeth wide; internal distal half gouge-like; with three oblique, subparallel keels; external margin with a subtriangular, smooth, depressed area on distal third, basal region irregularly rugose, with 5-6 setae in deep pores. Maxillolabial complex (Fig. 5G) partly sclerotized, with setae brown, stiff and erect; submentum, maxillary articulating areas and cardines fused, forming basal part; basal part with sparse short setae; distal maxilla: stipes, palpifer and mala with longer setae, denser on dorsal to ventral inner surface of mala; mala wide at base, apex rounded, with oblique sclerotized band near base; palpifer membranous with sclerotized ventral band at base; maxillary palpi trimerous; palpomeres sclerotized except distal band, with sparse small pores with internal channel and campaniform sensilla; basal palpomere with two dorsal short setae; median palpomere with two short setae (dorsal and lateral), distal palpomere with one dorsal subapical setae and numerous peg-shaped sensilla apically. Labium: prementum (prelabium) with basal sclerotized band projecting anterad between palpigers; palpigers membranous with short to long setae; labial palpi dimerous and partially sclerotized; palpomeres elongate; basal palpomere with three small campaniform sensilla; distal palpomere with peg-shaped sensilla at apex; ligula wide, anterior margin rounded, continuous with ventral hypopharynx, swollen, covered with thick short setae, shorter at base; mentum fused to submentum, submentum with a few asymmetrical short setae; mentum about 1.5 times wider than long with lateral margins rounded; a pair of long and other smaller setae parasagittally and short setae on anterior corners; one narrow, irregular sclerite on each side at base.
Thorax: prothorax (Fig. 3) about 2 times wider than long, as long as meso- and metathorax together. Pronotum weakly convex, more prominent posteriorly, anterior region with transverse darker area, densely covered with fine short and longer setae; disc with integument rugose and sparse setae, paler (whitish), except short groove on median line and angle-shaped lateral grooves darker; lateral pronotal furrow distinct. Ventral surface with sparse short and longer setae, denser anteriorly, epipleuron rectangular about 3 times longer than wide, lateropresternum distinctly separated from mediopresternum, mediopresternum subtriangular, anterior median margin rounded, notched posteromedially. Meso- and metathorax almost same size; integument smooth, except for a few fine setae, denser laterally; mesothorax with anterolateral large elliptical spiracle. Leg (Fig. 5H): short, inserted ventrolaterally; 4–segmented: coxa 3–4 times wider than long, with short and long setae and two campaniform sensilla; femur 1.3 times wider than long, with long setae medially and near distal margin; tibiotarsus about 1.5 times longer than wide with sparse short and long setae; pretarsus glabrous and tuberculate.
Abdomen (Figs. 3, 4): segments I–VIII subequal in size, IX 1.2–1.3 times longer than VIII, X reduced, apical and trilobed; integument smooth, with sparse fine setae, denser laterally and on segment X; segments I–VII each with retractile ambulatory ampullae on dorsal and ventral surfaces, dorsal ampullae divided by longitudinal furrow (grooved), and a pair of elliptical spiracles, shorter than mesothoracic spiracle; first one larger, the others decreasing in size posteriorly.
Pupa (female) (Fig. 6). Length: 31 mm.
Body (Figs. 6A, B). Coloration pale yellow, except for spines (tubercles), which are apically dark brown.
Head largely visible from above, shortly covered by pronotum (Fig. 6A). Integument mostly smooth and glabrous, except for sclerotized spines, each spine with one basal yellow seta, on dorsal surface and laterally of abdominal terga I-VII; spines increasing in size posteriorly.
Thorax (Fig. 6A). Pronotum transverse, anterior margin sinuous, forming two parasagittal lobes, lateral margins on median third produced and truncate; posterior third convergent posterad; pterothorax relatively small, as long as and narrower than prothorax, scutellar shield produced. Elytra almost reaching abdominal segment III.
Abdomen (Figs. 6A, B) with tergites I–VI transverse, increasing in width and length to tergite IV, then decreasing in width posteriorly; VII and VIII, semioval (posterior margin rounded), tergites I-VII with a transverse row of setigerous spines; VIII with a few reduced spines; segment IX transverse apically with four lobes (two dorsal and two ventral). Functional spiracles laterally on tergites I–VI, spiracle on VII reduced. Gin traps absent.
Material examined. Brazil, São Paulo state, Campos do Jordão municipality, 22°40′51.3″S, 45°35′30.6″W, alt. 1464 m, 13.X.2019, S. P. Rosa leg., 1 larva, 1 pupa, 1 larval exuviae (last instar), 1 pupal exuvia, 1 female (MZSP).
Type material examined. Brasil, Minas Gerais state, Passa Quatro municipality, Fazenda dos Campos, J. F. Zicán col., 16.XII.1915, male lectotype (MZSP 34367); same data, 25.XI.1919, female paralectotype (MZSP 34371).
Remarks. The specimens were collected in the early dry season from a decayed piece of wood (Fig. 1B) in a private legal reserve in Campos do Jordão (São Paulo state), an area characterized by anthropized and secondary mixed ombrophilous forest within the Atlantic Forest domain (Fig. 1A). While this is the first record of the species for São Paulo, the site belongs to the same orographic system as previous records from Virgínia and Passa Quatro municipalities (Minas Gerais state), all of which are situated within the Serra da Mantiqueira mountain range. Identification of the host plant was not possible due to the advanced state of decay of the chunk of wood. The reported host plant has been Nectandra sp. (Lauraceae) (Galileo, 1987).
4. Discussion
Casari and Nascimento (2019), in their attempt to characterize the tribes of Prioninae based on larval features, redescribed pupa and larva of Polyozalacordairei and described the larva and pupa of Quercivir gounellei. Based on their examinations and previous descriptions on the literature, they found that Meroscelisini larvae share some features, although not universally (Table 1): the lower boundary of epistoma is almost straight and not projecting over clypeus (except Tragosoma Audinet-Serville, 1832 and Trichoderes Chevrolat, 1843 species), the upper boundary weakly carinate (with rounded carina near condylar area) and slightly sinuous (except in Tragosoma and Trichoderes species, each with different types of processes); antennae with two antennomeres (but 3 antennomeres in Microplophorus magellanicus and Q. gounellei); stemmata present (but different numbers among species); legs short, 4-segmented; abdomen with retractile ambulatory ampullae dorsal and ventral; ampullae grooved and without asperites; and anus trilobed.
Comparison of larval features of Meroscelisus zikani Melzer, 1919 with the diagnostic features proposed by Casari and Nascimento (2019) for Meroscelisini. Present interpretations and observations in parentheses.
Meroscelisus zikani is more similar to Microplophorus magellanicus, Quercivir gounellei and Polyoza lacordairei (Table 1) by the epistoma shape (Fig. 5E), with upper boundary almost straight, not projecting above clypeus, and lower boundary with a rounded carina on each side near condylar area (weaker in Q. gounellei). It is even more similar to P. lacordairei by the number of antennomeres (2) (Fig. 5C), while in M. magellanicus and Q. gounellei the antenna is 3-articulated. M. zikani differs from all known larvae of the tribe by lacking stemmata.
The pupa of Meroscelisus zikani shares with other meroscelisine pupae (known only for Microplophorus magellanicus, P. lacordairei and Q. gounellei) the pronotum wider than long, without lateral projection. Gin traps are absent (Fig. 6A), like in M. magellanicus, while Q. gounellei and P. lacordairei have three and four pairs of gin traps, respectively. Meroscelisus zikani pupa is unique in having abdominal segment IX smooth, without microspines, and head largely exposed (Fig. 6A), while in the other species the abdominal segment IX has microspines and the head is almost totally covered by prothorax. Some of these differences may reflect the adult sexual dimorphism, since our M. zikani pupa and adult are females, while for other species the known pupae are males (Casari and Nascimento, 2019). In Meroscelisini, the dimorphism (Fig. 2) is widespread among species (Galileo, 1987), therefore more studies are needed on pupae of both sexes.
Most larval and pupal features attributed to Meroscelisini are actually shared with other Prioninae tribes (Casari and Nascimento, 2019). This suggests that the unstable classification within the Prioninae, including Parandrinae (Jin et al., 2023; Song et al., 2025; Şimşek et al., 2026), stems from the lack of a widely sampled phylogenetic framework to support taxonomic decisions, as emphasized by Casari and Nascimento (2019) in their comprehensive revision of Prioninae immature morphology.
Furthermore, the small number of immature stages currently known in Cerambycidae, compared to the vast diversity of this group, hinders generalizations and the recognition of diagnoses for species groups. In this sense, the revision by Casari and Nascimento (2019) represents a major advancement, but studies on cerambycid immatures are still much needed. We hope that the description of Meroscelisus zikani provided herein — the first for the tribe's type-genus will further contribute to the knowledge of immatures and the taxonomy of the group.
Acknowledgments
We are grateful to Antonio Santos Silva (MZSP) for type photos and to MZSP for facilities; to UNIFEI for the undergraduate research grant to D.P.M. This work was developed within the scope of the Instituto Nacional de Coleoptera (INCol) an INCT (National Institute of Science and Technology) by Brazil’s National Council for Scientific and Technological Development (CNPq) (408430/2024-9).
Data statement
The entire dataset supporting the results of this study is available within the article itself.
Funding
References
- Candèze, E., 1861. Histoire des métamorphoses de quelques coléoptères exotiques. Mem. Soc. R. Sci. Liege 16, 325-410.
-
Casari, S.A., Nascimento, F.E.L., 2019. Immature stages of american Prioninae Latreille, 1802: descriptions and phylogenetic considerations in Cerambycidae Latreille, 1802 (Coleoptera). Zootaxa 4568 (1), 113-138. https://doi.org/10.11646/zootaxa.4568.1.7
» https://doi.org/10.11646/zootaxa.4568.1.7 -
Casari, S.A., Biffi, G., Nascimento, F.E.L., 2025. Morphology of larvae and pupae of four species of Neotropical Acanthocinini (Cerambycidae, Lamiinae). Zootaxa 5590 (3), 325-344. https://doi.org/10.11646/zootaxa.5590.3.2
» https://doi.org/10.11646/zootaxa.5590.3.2 - Cekalovic, T., 1970. Descripción de la larva y pupa de Microplophorus magellanicus Blanchard, 1851 (Coleoptera-Cerambycidae). Bol. Soc. Biol. Concepc. 42, 333-339.
- Craighead, F. C., 1915. Larvae of Prioninae. Contributions toward a classification and biology of the North American Cerambycidae. Wash. Report. U. S. Dep. Agric. 107, 1-24.
- Duffy, E.A.J., 1960. A Monograph of the Immature Stages of Neotropical Timber Beetles (Cerambycidae). British Museum of Natural History, London, 327 pp.
- Galileo, M.H.M., 1987. Sistemática das tribos Meroscelisini e Anacolini (Coleoptera, Cerambycidae, Prioninae) nas Américas. I. Meroscelisini. Rev. Bras. Entomol. 31 (2), 141-367.
- Heller, H.M., 1904. Brasilianische Käferlarven, gesammelt von Dr. Fr. Ohaus. Entomol. Zeitung 65, 381-401.
-
Jin, M., Keyzer, R.D., Ashman, L.G., Zwick, A., Ślipiński, A. 2023. Phylogeny and tribal classification of Australian Prioninae (Coleoptera: Cerambycidae). Ann. Zool. 73 (3), 499-512. https://doi.org/10.3161/00034541ANZ2023.73.3.012
» https://doi.org/10.3161/00034541ANZ2023.73.3.012 -
Şimşek, B. S., Hansen, A. K., Solodovnikov, A., 2026. Morphology-based phylogeny of longhorn beetles (Coleoptera, Cerambycidae) aligns with phylogenomics and informs higher-level systematics. Cladistics cla.70041. https://doi.org/10.1111/cla.70041
» https://doi.org/10.1111/cla.70041 -
Song, N., Wang, M., Zhai, Q., Zhang, H., 2025. Insights into the phylogeny of longhorn beetles from phylogenomic data. Zool. J. Linn. Soc. 203 (1), zlae174. https://doi.org/10.1093/zoolinnean/zlae174
» https://doi.org/10.1093/zoolinnean/zlae174 - Švácha, P., Lawrence, J.F., 2014. Cerambycidae Latreille, 1802. In: Leschen, R.A.B., Beutel, R.G. (Eds.), Handbook of Zoology, Arthropoda: Insecta, Coleoptera, Beetles, Morphology and Systematics (Phytophaga). Vol. 3. Walter de Gruyter, Berlin, pp. 77-177.
-
Tavakilian, G., Chevillotte, H., 2026. Titan: base de données internationales sur les Cerambycidae ou Longicornes. Available in: http://titan.gbif.fr/ (accessed 23 January 2026).
» http://titan.gbif.fr/
