Research Article |
Corresponding author: Stephanie Haddad ( stephanyhaddad@gmail.com ) Academic editor: Marianna Simões
© 2021 Stephanie Haddad, Nayeli Gutiérrez, Felipe A. Noguera, Seunggwan Shin, Petr Svacha, Duane D. McKenna.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Haddad S, Gutiérrez N, Noguera FA, Shin S, Svacha P, McKenna DD (2021) Phylogenetic placement of the enigmatic longhorned beetle Vesperoctenus flohri Bates (Vesperidae) and a first description of its female internal structures. Arthropod Systematics & Phylogeny 79: 99-114. https://doi.org/10.3897/asp.79.e66966
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Taxonomic placement of the enigmatic monotypic Mexican longhorned beetle genus Vesperoctenus Bates is examined through inclusion in and reanalysis of the dataset of
Cerambycidae, distribution, Mexico, morphology, taxonomy, Vesperinae, Vesperoctenini
The taxonomic placement of the longhorned beetle Vesperoctenus flohri Bates has been highly controversial since its initial description by Bates in 1891. It is the only species within the genus Vesperoctenus Bates, is seldom collected, and is only known from Mexico (Baja California Sur, Durango, and Nuevo Leon;
Taxonomic placements of Vesperoctenus flohri in major publications since its formal description.
Taxonomic Placement | Reference |
A longhorned beetle “closely allied” to Vesperus Dejean, the name Vesperoctenus means “related to Vesperus but with comb-like antennae” (of male). |
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Placed in “Rhipiceridae” near Callirhipis Latreille (now Callirhipidae of Byrrhoidea). |
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Reconfirmed in the broad Cerambycidae of that time; |
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In Cerambycidae: Cerambycinae: Lepturini (in Aurivillius next to Vesperus and Paraphilus Gahan = Mantitheus Fairmaire, now in Philinae). |
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In Cerambycidae: Lepturinae: Vesperini. |
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In Vesperinae placed (together with Disteniinae, Oxypeltinae, and Philinae) as a subfamily of Crowson’s “Disteniidae” (the family should have been named Vesperidae for priority reasons); This is the first modern exclusion of Vesperinae including Vesperoctenus from the family Cerambycidae. |
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In Cerambycidae: Lepturinae: Lepturini. | Catalogs and checklists of Cerambycidae s. l. of the Western Hemisphere and Neotropics beginning with the original versions ( |
Incertae sedis within the newly defined Vesperidae (containing the Vesperinae and Philinae of Crowson, 1981, plus the newly added Anoplodermatinae). |
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In Vesperidae (with the placement of Anoplodermatinae in that family questioned) and closely related to Vesperus. |
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In Vesperidae in its own newly erected tribe Vesperoctenini. |
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Vesperoctenini (but not Vesperus) moved without explanation to Cerambycidae: Prioninae. |
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In Cerambycidae: Prioninae: Vesperoctenini (following |
Catalogs and checklists of Cerambycidae s. l. of the Western Hemisphere and Neotropics following the publication of Current versions of online cerambycid databases: |
In Vesperidae: Vesperoctenini as a genus and tribe of uncertain subfamilial position; placement in Prioninae rejected. |
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Recently, phylogenomic studies have greatly improved our understanding of Coleoptera systematics and evolution (e.g.,
N. Gutiérrez and P. Svacha collected a female specimen of V. flohri in Mexico, Baja California Sur, Sierra de la Laguna (23°32’60”N, 109°58’53”W, 1743 m) on 22 May 2018 at about 9:30 AM (Fig.
Documented localities of V. flohri were obtained from online databases, museum collections, and the literature. This information was stored in an Excel spreadsheet and then exported to the R statistical environment (
The legs, prothorax and right part of pterothorax were preserved for DNA and the remaining body was treated in hot 5% KOH to dissolve soft tissues. The cleaned cuticle was opened by microscissors to expose the internal structures – ovipositor, internal genitalia, metathoracic furca (metendosternite), and tentorium.
We used anchored hybrid enrichment (AHE;
Anchored hybrid enrichment data for Vesperoctenus was trimmed with Trimmomatic v 0.36 (
A script from Orthograph (
PartitionFinder v. 2 (
We conducted a partitioned maximum likelihood (ML) analysis (1000 rapid bootstrap replicates) for NT data (781,854 bp) in RAxML 8.2.12 (
Excluding the placement of Vesperoctenus which we here report for the first time, the recovered relationships and clades in the partitioned maximum likelihood phylogeny for nucleotide data (Fig.
Partitioned maximum likelihood phylogeny for nucleotide data. Maximum likelihood bootstrap support (MLBS) is shown only for nodes with MLBS ≤ 95%. Information regarding the systematics of the sampled exemplars is indicated on the right of the tree. Photograph of male Vesperoctenus flohri from Zacatecas (Sierra de Organos) by Juan Carrillo Contreras.
For terminology, see
The tentorium agrees with other Vesperidae (
Unlike the male hind coxae which are close together (Fig.
(a) Vesperoctenus flohri, male, hind coxae, ventral view (the dense ventral pilosity was largely removed); (b) Vesperus strepens, male (cleared specimen), dtto; (c) V. strepens, male (cleared specimen), metendosternite, dorsal view. Lettering: arm – metendosternal arm; at – anterior tendon; lam – metendosternal lamina; st – basal stem.
(all cleared specimens). (a) Vesperoctenus flohri, female, hind coxae, ventral view; (b) V. flohri, female, metendosternite, dorsal and slightly anterior view (tip of right arm missing); (c) Vesperus strepens, female, hind coxae, ventral view; (d) V. strepens, female, metendosternite, dorsal view; (e) Mantitheus pekinensis, female, hind coxae, ventral view; (f) M. pekinensis, female, metendosternite, dorsal view (tip of left arm missing). Lettering: arm – metendosternal arm; at – anterior tendon; lam – metendosternal lamina; st – basal stem (missing in females of Vesperoctenus and Vesperus).
Female terminalia and internal genitalia. Sternum VIII has a V-shaped sclerotization and long spiculum gastrale (Fig.
Vesperoctenus flohri, female genitalia and sternum VIII. (a) Ovipositor and internal genital tract, ventral view; (b) ovipositor, dorsal view; (c) abdominal sternum VIII and membranous tube ensheathing the ovipositor, ventral view; (d) detail of internal genital tract. Lettering: a – anus; bc – bursa copulatrix; cb – coxital baculum; cl – coxite lobe; co – common oviduct; db – dorsal baculum; gpo – gonopore; hg – hindgut; ip – intersegmental pouches; lo – lateral oviduct; lptb – lateral proctigeral baculum; m – membranous tube ensheathing ovipositor; mptb – medial proctigeral baculum; ppb – paraproctal baculum; sp – spermatheca; spd – spermathecal duct; spgl – spermathecal gland; sty – stylus; sv – spiculum ventrale (apodeme of sVIII); sVIII – sternum VIII; vg – vagina.
The lack of V. flohri larvae and molecular data (until now), the scarcity of available adult specimens, and the disjunct distribution of vesperids (not many Old World taxonomists had specimens available for comparison) has rendered the evaluation of the relationships and systematic placement of the genus Vesperoctenus difficult and variable (see Introduction and Table
Refer to
Vesperoctenus (as well as Vesperus and the Philinae) does not share most of the probable synapomorphies of the Neotropical Anoplodermatinae: procoxal cavities closed externally (open in other Vesperidae); wing invariably without a wedge cell (wedge cell present in macropterous specimens of Philinae, Vesperoctenus and some Vesperus) and with MP3+4 attached to MP1+2 at about half length of the latter (at about one-third length or less in all other Vesperidae and in most other non-chrysomelid chrysomeloids); metendosternite in dissected species (both sexes of Pathocerus and Migdolus, male of Hypocephalus) without laminae (with laminae in males and most females of other dissected Vesperidae including the modified metendosternites of some flightless females, although strongly reduced in females of some species of Vesperus, see below and Fig.
Svacha (in
No reliable synapomorphies could be found for the Philinae + Vesperinae clade because some adults of Philinae are morphologically very generalized cerambyciforms or even chrysomeloids and all similarities are probably plesiomorphic or at least difficult to interpret. The interpretation of larval characters is also difficult (
Vesperoctenus, Vesperus, and known Philinae share the large thin flattened dorsal tentorial arms; in dissected Anoplodermatinae these arms are present but are short and tapering or rod-like, not broad and flattened. Large dorsal arms should be plesiomorphic and although the broad flat almost foliar dorsal ends are unusual, we cannot decide whether such dorsal arms were present in the vesperid ancestor and reduced in the Anoplodermatinae, or whether the broad flat dorsal ends may represent a synapomorphy of the Philinae and Vesperinae.
It would be difficult to list any synapomorphies of the Philinae because of the above mentioned generalized plesiomorphic morphology of some philine taxa. However, Philinae were represented by three relatively different genera (Philus, Spiniphilus Lin & Bi and Mantitheus, the latter with brachelytrous micropterous females resembling females of some Vesperus) in the mitochondrial phylogeny of
1. Head with large inflated occipital region and then abruptly constricted into a narrow neck not including posterior gular region and metatentorial slits. This head type (similar to, but in details, different from that of some lepturine or lepturine-like Cerambycidae in which the neck does include metatentorial slits) is virtually unknown in other groups of the non-chrysomelid Chrysomeloidea.
2. Modified female metendosternite. Unlike the metendosternites in the flying males of the Anoplodermatinae which have the common basal stem but lack the laminae, those of the Philinae + Vesperinae clade are “hylecoetoid” (sensu
3. Wing, even in macropterous specimens, with at most, a narrow reduced wedge cell (missing in some Vesperus); that cell is always large in macropterous Philinae (figures in
4. Vesperus and Vesperoctenus share the prominent procoxae and reduced narrow intercoxal process. In Philinae the intercoxal process is high and broad and the procoxae, although relatively prominent, are inserted under the process and articulating on it, occasionally by a distinct tubercle (
Autapomorphies of Vesperoctenus include: the 12-segmented antennae (the terminal flagellomere may be appendiculate but never completely divided in the other Vesperidae), possibly the very broad (high) metanepisternum (Fig.
No reliable synapomorphies could be found for the sister genus Vesperus. Females often have shortened elytra, but in some species, they are about as well developed as in females of Vesperoctenus and in Vesperus macropterus Sama even the female wings are fully developed and can be used (together with the well-developed elytra) for parachuting from the tall dry herbs whose inflorescences the females oviposit in (Sechi 2011). The desclerotized spermatheca lacking the spermathecal gland (which can no longer be considered synapomorphic for the Philinae + Vesperinae clade) would be a synapomorphy of Vesperus if its presence is universal within the genus, but so far it can be confirmed for only two species (V. strepens and V. luridus).
Other characters occasionally employed in the classification of this group are not helpful in evaluating the relationships and taxonomic position of Vesperoctenus. The lateral pronotal margin or carina is present in the Anoplodermatinae and virtually absent in Vesperinae, but it may be present or absent with various transitions in Philinae. The most complete pronotal margin occurs in the flightless females of Heterophilus (
Vesperoctenus flohri has rarely been collected and historically appears to have a very narrow geographic distribution which raises concerns about its conservation status. Few specimens of V. flohri are available in museum collections and only a handful of collection records exist in the published literature which have so far limited the distribution of this species to only three Mexican states (Baja California Sur, Durango, and Nuevo Leon). Interestingly, we found a few online observations of the species (on Facebook and iNaturalist) that expand its known geographic distribution to include the Mexican states of Tlaxcala, Veracruz, and Zacatecas (Fig.
Sixty percent of Vesperoctenus records are located in or near national and state protected natural areas with high biological diversity (
We would like to thank Drs. Paulina Cifuentes Ruiz and Santiago Zaragoza Caballero (UNAM) for their assistance with the logistics of our collecting trip in Sierra de la Laguna and support in obtaining the required permits. We are grateful to Martin Cota, Forest Keeper of the Sierra de la Laguna Biosphere Reserve, who kindly helped us during the collecting trip, and to Juan Carrillo and Santiago Jaume-Schinkel for information on the habitat where they found Vesperoctenus. We would also like to thank Alejandra Barrios Sifuentes, Lazaro Rangel Castaneda, and Jesús Quiñonez Gómez (CONANP, Sierra de La Laguna Biosphere Reserve) for approving and facilitating our stay on the reserve. Finally, we thank Meiying Lin (Institute of Zoology, Chinese Academy of Sciences, Beijing) for information on the female metendosternite of Heterophilus. This research was funded in part by NSF grant DEB-1355169 to DDM.