A new species of Zethus (Zethoides) Fox, 1899 (Hymenoptera, Vespidae) from South America

Abstract

Zethus is the most speciose genus among vespid wasps and has become even larger after the inclusion of closely related taxa as subgenera after a morphological phylogenetic analysis. Despite being taxonomically reviewed in the past, the Neotropical diversity of the group demonstrates potential for even further growth. A new species of Zethus (Zethoides) Fox, 1899 is herein described, being the fifth one to be described in this subgenus after the great taxonomic revision of the genus in the New World.

Keywords:
Morphology; Taxonomy; Zethus biglumis species-group

INTRODUCTION

Although more popularly known by their social representatives such as hornets and paper wasps, most of the Vespidae diversity lies in Eumeninae, mostly represented by solitary wasps. Zethus Fabricius, 1804 is the largest genus in this subfamily, with nearly 300 species and is currently divided into nine subgenera with some species-groups being trated as Incertae sedis (Lopes et al., 2021). Zethus (Zethoides) Fox, 1899 is a well stablished monophyletic subgenus that comprises mostly Neotropical representatives in 43 species, from the United States to Argentina (Lopes & Noll, 2018; Lopes et al., 2021). Few descriptions of new taxa have been provided for the subgenus after its New World revision (Bohart & Stange, 1965), with Z. carpenteri described in the Z. carinatus group (Stange, 1997), Z. anomalus described by Cooper (1999) and later assigned to the Z. olmecus group (Lopes et al., 2020) and Z. milleri described by Stange (1997) and Z. denticlypeus in Lopes et al. (2020), both assigned to the Z. biglumis group. The Zethus biglumis species-group currently contains 18 species, including those previously belonging to the Z. clypearis group, and represents the most diverse assemblage in Z. (Zethoides) (Lopes & Noll, 2018; Lopes et al., 2020).

Obtained from museum collections, four examined specimens 1), three of which collected at least 30 years ago, key out in Bohart & Stange’s (1965), key as Zethus lunaris Zavattari, 1912 within the Z. biglumis group, baring a wedge-shaped petiole in posterior view. However, the distribution is further south than the expected and closer examination led to the observation of characters that easily define them as belonging to a new species, which is herein described.

MATERIAL AND METHODS

Four examined specimens, two males, one deposited in the Coleção Entomológica Padre Jesus Moure, of the Universidade Federal do Paraná, Curitiba, Brazil (DZUP) and one deposited in the Naturalis Biodiversity Center, Leiden, Netherlands (NBCN), and two females, deposited in the American Museum of Natural History, New York, USA (AMNH) were examined and identified to species according to Bohart & Stange’s (1965) key. For subgenus designation, the key in Lopes et al. (2021) was also used. Running to Z. lunaris, these insects were compared to type material of both subspecies (Z. l. lunaris and Z. l. cooperi) deposited in the AMNH and the Zoologisches Museum und der Humboldt-Universität zu Berlin, Berlin, Germany (ZMHB). Data about type specimens of the new species are brought under the Examined material section, while Z. lunaris specimens used for comparison are brought under the Additional material section.

Specimens were examined with the aid of a M205 C stereoscope and photographed with an attached Flexacam C1 camera using the LASx software. Image stacking was done in the Helicon Focus software. Adobe Photoshop was used for minor editions (brightness and contrast) and mounting plates.

Due to the age of the male paratype specimen, it was chosen not to risk its integrity by attempting genitalia extraction.

Terminology follows Bohart & Stange (1965) and Carpenter & Garcete-Barrett (2002). Abbreviations are used in the text for tergum (T), sternum (S) and flagellomere (F). Terga and sterna are followed by Arabic numbers indicating their respective segment. Flagellomeres are followed by Roman numerals indicating their respective segment.

RESULTS AND DISCUSSION

The examined specimens key out as belonging to the Zethus (Zethoides) Fox, 1899 subgenus, presenting all modifications on the third metasomal tergum, such as the apical projection, trilobate secondary lamella, primary lamella laterally tapered, and lateral indent, as well as in the S3 with reduced lamella and developed medial lamellar lobe (Bohart & Stange, 1965; Lopes & Noll, 2018 - see figs. 5A, 9B); Lopes et al., 2021 - see fig. 10). Further identification reveals them to be inserted in the Z. biglumis species group, bearing the tegula posteriorly angled (Fig. 1E) and the discoid puncture on a tubercle (Fig. 1F) (Lopes & Noll, 2018). As mentioned previously, the specimens run to Z. lunaris, but are quite distinct from this known species, presenting differences that are more outstanding than the difference between subspecies. It is worth noting that the subspecies of Z. lunaris are not discussed here as there were no morphological traits that varied besides the petiole, already mentioned by Bohart & Stange (1965) and the only male specimens obtained were types and, therefore, not dissected to examine their genitalia.

Figure 1
Male (A, B) and female (C, D) of Zethus latipetiolatus Lopes, sp. nov. and synapomorphic characters for the Z. biglumis species group (E, F). (A, C) Lateral habitus. (B, D) Head, frontal view. (E) Discoid puncturestanding on tubercle. (F) Tegula posteriorly bowed. Scales: (A, C) 5,0 mm; (B, D) 1,0 mm; (E, F) 0,5 mm.

Zethus (Zethoides) latipetiolatus Lopes, sp. nov.

Diagnosis: The first metasomal tergum (Fig. 2) with extremely expanded posterior flaps is unique in the subgenus. The last male falgellomere slender and apically rounded, male clypeus with deep trapezoid concavity, male mandible with quadrate incision between teeth II and III, tubercle of discoid puncture rising gradually and apical propodeal lamella oblique and close to the valvula also help to separate it from Z. lunaris.

Figure 2
Petioles of Zethus latipetiolatus Lopes, sp. nov. (A, B) and Z. lunaris cooperiBohart & Stange, 1965 (C, D) in profile (A, C) and dorsal view (B, D). Scales: 1,0 mm.

Description: Male: Coloration: Black, with yellow markings as follows: ventral surface of scape; pair of spots above antennal sockets; band following base of pronotal carina; pronotal lobe; medial section of posterior margin of pronotum; spot on posterior portion of tegula; parategula; pair of spots on scutellum; pair of spots on metanotum; stripe on outer surface of hindtibia; strong subapical bands on T1 - 3 and S2 - 3, weak ones on T4 - 5 and S4 - 5. Testaceous: antennae except dorsal surface of scape; tibiae; tarsi; tegula. Structure: Apicalflagellomere slender and digitiform. Clypeal apex with deep, trapezoid concavity. Mandible with a deep quadrate incision between teeth II and III. Genal margin slightly sinuous. Pronotum with humeri rounded, but with distinct dorsal and lateral surfaces. Subhumeral area very narrow. Tegula posteriorly angulated, with outer margin nearly transversal on posterior end. Parategula digitiform. Scutellum flat. Propodeum with rounded angles and posterior and lateral surfaces well separated by lateral carina. Apical propodeal lamella subquadrate, obliquely oriented on insertion and ending right above valvula. T1 convex in profile, with large and wide posterior flap-like extensions ventro-laterally projected. Stem of T2 very short. Apical lamella of T2 wider laterally. Sculpture: Clypeus, vertex and gena with moderately macropunctation intercalated by dense micropunctation. Frons with shallow coalescent macropunctures with cariniform interspaces. Admedial lines present. Pronotum with moderate macropunctation, a few coalescent. Mesoscutum and scutellum with sparse macropunctation intercalated by dense micropunctation. Discoid puncture present, on a low and gradually raised tubercle. Notauli absent. Mesepisternum with macropunctures and smooth interspaces. Metanotum with overall coarse irregular punctures and with lateral carina not curved inwards, restricted to sides of sclerite. Propodeum with strong and complete submedian and lateral carinas, with the later lamellar. Transverse/oblique striae on posterior propodeal surface and on lateral surface but only adjacent to lateral carina. T1 - 2 with sparse, small and weak macropunctures intercalated by dense micropunctation. S2-3 with moderate macropunctation and smooth interspaces. Subapical bands of T1 - 3 and S2 - 3 smooth. Pilosity: Overall very dense, short, golden tomentum. Long, thick, outstanding bristles on: clypeus, frons and metanotum; sparse on pronotum; thin on mesepisternum, propodeum and S1; short and sparse on base of T1; absent elsewhere. Fore wing length: 11,1 mm.

Female: as in male, except: Coloration: antennae and legs without yellow markings. Structure: Clypeal apex slightly convex with subapical ridge. Sculpture: overall punctation slightly weaker and sparser. Lateral carina not lamellar. Pilosity: similar to that of male. Fore wing length: 13,4 mm and 14.4 mm.

Etymology: The epithet makes reference to the greatly expanded and broad T1, a unique trait in the subgenus so far.

Examined material: HOLOTYPE: Brasil, RO, Itapuã do Oeste, Flona do Jamari,/9.145°S, 63.011°W,/ 70m, 7­-15.vi.2013/ Bueno, Luz & Williams [♂, DZUP] . PARATYPES: Satipo, Peru/ 2.xii.’37, 750alt/ Deskandahl [♂, NBCN]; BOLIVIA, iii.95/ Chapare-Sajito/Ariagada [♀, AMNH]; BOLIVIA, Buena Vista/ Depto. Santa Cruz/10.i.1991/ Carpenter & Wenzel [♀, AMNH].”

Additional material: Z. lunaris cooperiBohart & Stange, 1965. Barro Colorado/ CZ, Panamá/ N Banks [PARATYPE, ♂, AMNH]. Z. lunaris lunaris Zavattari, 1912. Columbien, Cauca, Rahde [LECTOTYPE, ♂, ZMHB]. Same data as lectotype [LECTOPARATYPE, ♀, ZMHB]. Same data as lectotype [label “type”, ♂, ZMHB]. PANAMÁ: Canal Zone Area/ Pipeline Road/ 13.xii.1990/ Carpenter & Wenzel [♀, AMNH]. Canal Zone, Pan./ Barro Colorado I./ ix.17.1978/ RB & LS Kimsey [♀, AMNH]; same data, ix.25.1978 [♀, AMNH].

Observations: The new species is undoubtedly closely related to Z. lunaris, with very similar clypeus in females, most of the mesosoma, except the propodeum and the T1. Nevertheless, features in the male mandible, male F11, occipital carina, discoid puncture, apical propodeal lamella and T1 readily separate the new species from Z. lunaris (Table 1, Fig. 3).

Table 1
Diagnostic characters for differentiating Zethus latipetiolatus Lopes, sp. nov. from Z. lunaris Zavattari. 1912.

Character	Species
	Z. latipetiolatus	Z. lunaris
T1, expansion	more gradual in profile, becoming much wider apically; larger apical flaps directed outwards (Fig. 2A, B)	more abrupt in profile, apical width not much greater than at middle of expansion; small apical flaps, directed downwards (Fig. 2C, D)
T1, punctation	smooth with sparse micropunctation (Fig. 2A, B)	macropunctate (Fig. 2C, D)
T1, pilosity	Only tomentum; bristles absent (Fig. 2A, B)	Tomentum absent; long erect thick bristles (Fig. 2C, D)
Occipital carina	shorter, straightly raised (Fig. 3A)	higher, reflexed (Fig. 3B)
Last male flagellomere	slender, apically rounded (Fig. 3C)	wider, apically truncate (Fig. 3D)
Male clypeus, apex	Trapezoid concavity (Fig. 3E)	Semicircular concavity (Fig. 3F)
Male mandible, incision between teeth II and III	Smaller, quadrate (Fig. 3E)	Larger, rounded (Fig. 3F)
Tubercle of discoid punture	only slightly and gradually raised (Fig. 3G)	evidently and abruptly raised (Fig. 3H)
Apical propodeal lamella.	Oblique, ending right above valvula (Fig. 3I)	Horizontal, well-spaced from valvula (Fig. 3J)

Figure 3
Diagnostic characters for differentiating Zethus latipetiolatus Lopes, sp. nov. (A, C, E, G, I) from Z. lunaris Zavattari. 1912 (B, D, F, H, J). (A, B) Zoom of vertex and occiput of head, lateral view; arrow indicates occipital carina. (C, D) Lateral view of the apex of male flagellum. (E, F) Oblique view of the apex of the clypeus (cl) and mandibles; arrow indicates mandibular incision. (G, H) Zoom of lateral portion of mesoscutum adjacent to tegula (tg); arrow indicates discoid puncture. (I, J) Lateral view of propodeal apex; arrow indicates apical propodeal lamella. Scales: 0,5 mm.

CONCLUSION

This contribution is another addition to the ever-growing diversity of Zethus. This is only the fifth new species described in subgenus Zethus (Zethoides) since Bohart & Stange’s (1965) revision, even though one of the paratypes had been already collected at the time of that study. This shows that entomological collections still have great deal of material to be examined despite the great amount of effort already carried out in past studies.

ACKNOWLEDGEMENTS:

I thank institutions and curators that provided material for the study, and Eduardo A.B. Almeida for infrastructural support.

REFERENCES

• Bohart, R.M. & Stange, L.A. 1965. A Revision of the genus Zethus Fabricius in the Western Hemisphere (Hymenoptera: Eumenidae). University of California Publications in Entomology, 40: 1-208.
• Carpenter, J.M. & Garcete-Barrett, B.R. 2002. A key to the Neotropical genera of Eumeninae (Hymenoptera: Vespidae). Boletín del Museo Nacional de Historia Natural del Paraguay, 14: 52-73.
• Cooper, M. 1999. A new species of Zethus F. (Hym., Vespidae, Eumeninae) with unusual male genitalia. Entomologist’s Monthly Magazine, 135: 39-42.
• Lopes, R.B. & Noll, F.B. 2018. Cladistic analysis of the Zethus (Zethoides) (Hymenoptera, Vespidae, Eumeninae) species groups with insights on the current subgeneric classification of Zethus Fabricius, 1804. Insect Systematics & Evolution, 49(2): 103-129. https://doi.org/10.1163/1876312X-00002165
  » https://doi.org/10.1163/1876312X-00002165
• Lopes, R.B.; Carpenter, J.M. & Noll, F.B. 2021. Cladistic analysis of Zethus Fabricius, 1804 (Hymenoptera, Vespidae): a new subgeneric classification. Journal of Hymenoptera Research, 82: 253-283. https://doi.org/10.3897/jhr.82.65760
  » https://doi.org/10.3897/jhr.82.65760
• Lopes, R.B.; Cruciol, A.H. & Noll, F.B. 2020. Notes on Zethini (Hymenoptera, Vespidae, Eumeninae): complementary sex descriptions, synonymies and a new species of Zethus Fabricius. Zootaxa, 4743: 232-246. https://doi.org/10.11646/zootaxa.4743.2.6
  » https://doi.org/10.11646/zootaxa.4743.2.6
• Stange, L.A. 1997. The Zethus of Venezuela (Hymenoptera: Eumenidae). Insecta Mundi, 11(3-4): 311-324.

• FUNDING INFORMATION:

  São Paulo Research Foundation (FAPESP) grant #2021/00766-0.

Edited by:

Helena Carolina Onody

Publication Dates

• Publication in this collection
  07 Nov 2022
• Date of issue
  2022

History

• Received
  11 May 2022
• Accepted
  18 Aug 2022
• Published
  01 Sept 2022