Wikipedia

Ischyrus

Ischyrus is a large American genus of pleasing fungus beetles (family Erotylidae), containing about 85 described species. They are placed in subfamily Tritominae, or – in taxonomic arrangements that prefer a more comprehensive subfamily Erotylinae – in tribe Tritomini of the Erotylinae.[1][2]

Ischyrus
Ischyrus quadripunctatus
Scientific classification Edit this classification
Kingdom: Animalia
Phylum: Arthropoda
Clade: Pancrustacea
Class: Insecta
Order: Coleoptera
Suborder: Polyphaga
Infraorder: Cucujiformia
Family: Erotylidae
Subfamily: Tritominae
Genus: Ischyrus
Lacordaire, 1842
Type species
Erotylus quadripunctatus
Olivier, 1792
Synonyms

Micrischyrus Alvarenga, 1965

This genus has a convoluted nomenclatural history involving the related genera Lybas, Megischyrus and Mycotretus.[3]

Taxonomy and nomenclature

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The genus names Ischyrus, Lybas and Mycotretus were first published by Pierre Dejean in the second edition of his Catalogue des Coléoptères in 1836[4]; however, he attributed these names to Louis Chevrolat instead of claiming authorship himself. Dejean's catalog was a simple list of names, with no diagostic criteria or descriptions, but as he included well-known species that hat been extensively described by previous authors in each of his genera, his genera are technically valid.[3]

Jean Lacordaire in 1842 published a monograph on the pleasing fungus beetles. Therein, he also used the genus names Ischyrus, Lybas and Mycotretus, attributing them to Chevrolat just as Dejean did. However, Lacordaire placed Dejean's Lybas species in Mycotretus and re-established the genus Lybas for Lybas normalis, a species mentioned by preceding authors such as Dejean, but never validly described until Lacordaire's 1842 work. Meanwhile, most of Dejean's small Mycotretus species were moved into Ischyrus by Lacordaire, where they formed a second "division" (subgenus) distinct from the large tropical species which had already been placed in Ischyrus by Dejean.[3]

In 1873, George Crotch split genus Ischyrus, elevating Lacordaire's groups to full genus status. But he retained the name Ischyrus for the second group, which had been treated as Mycotretus by Dejean. The first group, Dejean's Ischyrus, was named Megischyrus by Crotch, formally fixing its type species as the Erotylus undatus described by Guillaume-Antoine Olivier, which was also listed first in Dejean's list of Ischyrus species. For his Ischyrus, Crotch designated Olivier's Erotylus quadripunctatus as type species. As he only referred back to Lacordaire, Crotch overlooked that Dejean had included this species in Mycotretus, preventing its use as type species of Ischyrus.[3]

Subsequent authors applied the genus names as proposed by Crotch, until Moacyr Alvarenga in 1965 revalidated Dejean's Ischyrus with E.undatus as type species, making Megischyrus a junior objective synonym and invalidating it. For the second group, containing the smaller species of Lacordaire's Ischyrus, Alvarenga established the genus Micrischyrus, with E.quadripunctatus as type species to exactly replace Crotch's Ischyrus which had become a junior homonym by the abolishment of Megischyrus, and likewise invalidated. However, almost all Erotylidae research at that time was published in English, with Japanese and German having some minor relevance due to prolific experts Michio Chûjô and Kurt Delkeskamp, whereas Alvarenga published in Brazilian Portuguese and his nomenclatural acts appeared in the then little-known zoological bulletin of the Federal University of Paraná (now Acta Biologica Paranaense). Consequently, unaware of Alvarenga's proposed solution to a problem they often were not even aware of in the first place, other erotylid researchers continued to apply Crotch's nomenclature.[3]

To resolve this situation, Paul E. Skelley and Michael A. Goodrich in 1994 petitioned the ICZN to rule Dejean's descriptions as invalid; this would preserve the prevailing genus assignments, as the Ischyrus/Micrischyrus scheme had not been used much outside Alvarenga's own publications, and all the late-20th century landmark studies and major species catalogs used the Megischyrus/Ischyrus scheme. In 1996, the ICZN agreed to this proposal, establishing Lacordaire as the author of Ischyrus due to Crotch's revalidation of his taxon. This also permitted E.quadripunctatus to be type species of Ischyrus, courtesy of Lacordaire having moved it there.[5]

Species

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As per Crotch's understanding, this genus unites most of small species from the "second division" of Lacordaire's Ischyrus, namely the group around the type species I.quadripunctatus; hence Alvarenga's proposed name Micrischyrus (meaning "tiny Ischyrus"):[6]

References

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  1. ↑ "Genus Ischyrus". iNaturalist. Retrieved 2022-10-21.
  2. ↑ "Ischyrus Lacordaire, 1842". www.gbif.org. Retrieved 2022-10-21.
  3. 1 2 3 4 5 Skelley, Paul E. & Goodrich, Michael A. (1994): Case 2885. Ischyrus Lacordaire, 1842, Lybas Lacordaire, 1842, Mycotretus Lacordaire, 1842 and Megischyrus Crotch, 1873 (Insecta, Coleoptera): Proposed Conservation. Bull. Zool. Nomenclat. 51(2): 128-132. doi:10.5962/bhl.part.7176 PDF fulltext
  4. ↑ Sometimes erroneously dated to 1837.
  5. ↑ ICZN (1996): Opinion 1824. Ischyrus Lacordaire, 1842, Lybas Lacordaire, 1842, Mycotretus Lacordaire, 1842 and Megischyrus Crotch, 1873 (Insecta, Coleoptera): conserved. Bull. Zool. Nomenclat. 53(1): 54-56. Fulltext
  6. ↑ Alvarenga, Moacyr (1994): Catálogo dos Erotylidae (Coleoptera) Neotropicais. [Catalogue of Neotropical Erotylidae (Coleoptera). Portuguese with English abstract.] Revista Brasileira de Zoologia 11(1): 1-175. doi:10.1590/S0101-81751994000100001.

Further reading

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