The Lymexylidae (historically often spelled Lymexylonidae), also known as ship-timber beetles, are a

family Family (from la, familia) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its ...

of wood-boring beetles. Lymexylidae belong to the suborder

Polyphaga Polyphaga is the largest and most diverse suborder of beetles. It comprises 144 families in 16 superfamilies, and displays an enormous variety of specialization and adaptation, with over 350,000 described species, or approximately 90% of the b ...

and are the sole member of the superfamily Lymexyloidea.

Habitat and behavior

''Lymexylon'', ''Elateroides'', and ''Melittomma'' are pests to forest trees such as

chestnut The chestnuts are the deciduous trees and shrubs in the genus ''Castanea'', in the beech family Fagaceae. They are native to temperate regions of the Northern Hemisphere. The name also refers to the edible nuts they produce. The unrelat ...

, poplar, and

oak An oak is a tree or shrub in the genus ''Quercus'' (; Latin "oak tree") of the beech family, Fagaceae. There are approximately 500 extant species of oaks. The common name "oak" also appears in the names of species in related genera, notably ''L ...

, and can be found worldwide. Some species are parasitic, causing decay in living trees and damaging timber structures such as houses and ships. Wood boring activities occur primarily in the larva stage, with the larvae damaging both sapwood and heartwood. Lymexylidae

larva A larva (; plural larvae ) is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle. The ...

e bore into living and decaying wood (e.g.

Chestnut The chestnuts are the deciduous trees and shrubs in the genus ''Castanea'', in the beech family Fagaceae. They are native to temperate regions of the Northern Hemisphere. The name also refers to the edible nuts they produce. The unrelat ...

Populus ''Populus'' is a genus of 25–30 species of deciduous flowering plants in the family Salicaceae, native to most of the Northern Hemisphere. English names variously applied to different species include poplar (), aspen, and cottonwood. The we ...

, and

Oak An oak is a tree or shrub in the genus ''Quercus'' (; Latin "oak tree") of the beech family, Fagaceae. There are approximately 500 extant species of oaks. The common name "oak" also appears in the names of species in related genera, notably ''L ...

) where they consume the fungus '' Endomyces hylecoeti''.

Symbiotic relationship with fungi

Lymexylidae larvae have a symbiotic association with certain types of fungi. The fungi grow in sheltered environments where they are tended by the larvae, such as the holes burrowed into the wood and, in return, the larvae feed on the fungi. Specifically, this species has evolved a relationship with the yeast-like fungus ''Endomyces hylecoeti''. Every egg the female lays is coated with fungal spores from a pouch near her ovipositor. The larvae hatch and subsequently collect some of the spores by remaining close to the egg shells for a period of time, before tunneling further into the wood. The fungi grow on the tunnel walls created by the larvae. The larvae then consume the fungus, rather than the wood itself. As the fungi require air flow to grow, the larvae ensure the tunnels are free of any debris.

Species and Genera

Lymexylidae contain the following genera:Lymexylidae Species List
at Joel Hallan's Biology Catalog. Texas A&M University. Retrieved on 17 May 2012. * '' Atractocerus'' Palisot de Beauvois, 1801 * '' Australymexylon'' Wheeler, 1986 * '' Elateroides'' Schaeffer, 1766 * ''

Lymexylon ''Lymexylon'' is a genus of beetles in the family Lymexylidae, containing the following species:Melittomma'' Murray, 1867 * '' Melittommopsis'' Lane, 1955 * '' Protomelittomma'' Wheeler, 1986 * '' Urtea'' Paulus, 2004 *†'' Adamas'' Chen & Zhang, 2020

Burmese amber Burmese amber, also known as Burmite or Kachin amber, is amber from the Hukawng Valley in northern Myanmar. The amber is dated to around 100 million years ago, during the latest Albian to earliest Cenomanian ages of the mid-Cretaceous period. The ...

, Myanmar, Late Cretaceous (

Cenomanian The Cenomanian is, in the ICS' geological timescale, the oldest or earliest age of the Late Cretaceous Epoch or the lowest stage of the Upper Cretaceous Series. An age is a unit of geochronology; it is a unit of time; the stage is a unit in the s ...

) *†'' Cratoatractocerus'' Wolf-Schwenninger 2011

Crato Formation The Crato Formation is a geologic formation of Early Cretaceous ( Aptian) age in northeastern Brazil's Araripe Basin. It is an important Lagerstätte (undisturbed fossil accumulation) for palaeontologists. The strata were laid down mostly duri ...

, Brazil, Early Cretaceous (

Aptian The Aptian is an age in the geologic timescale or a stage in the stratigraphic column. It is a subdivision of the Early or Lower Cretaceous Epoch or Series and encompasses the time from 121.4 ± 1.0 Ma to 113.0 ± 1.0 Ma (million years ago), a ...

) *†'' Cretoquadratus'' Chen 2019 Burmese amber, Myanmar, Cenomanian *†'' Ponomarenkylon'' Kirejtshuk 2008

Baltic amber The Baltic region is home to the largest known deposit of amber, called Baltic amber or succinite. It was produced sometime during the Eocene epoch, but exactly when is controversial. It has been estimated that these forests created more than 1 ...

Eocene The Eocene ( ) Epoch is a geological epoch (geology), epoch that lasted from about 56 to 33.9 million years ago (mya). It is the second epoch of the Paleogene Period (geology), Period in the modern Cenozoic Era (geology), Era. The name ''Eocene' ...

*†'' Vetatractocerus'' Yamamoto 2019 Burmese amber, Myanmar, Cenomanian There are over 60 species in these genera, including: * The ship timber beetle, ''

Lymexylon navale ''Lymexylon'' is a genus of beetles in the family Lymexylidae, containing the following species:Elateroides lugubris'' (Say) and the chestnut timberworm, '' Melittomma sericeum''

Morphology

Adult morphology: * long; elongate to slender, parallel-sided, vestiture consisting of fine setae; conspicuously necked to not necked; somewhat waisted. *Head short, typically narrowed behind large protruding eyes forming a slight neck; surface punctate, with or without epicranial pit. *Antennae short 11-segmented, filiform/serrate and often sexually dimorphic. *Maxillary palpi 4-segmented, simple in most females, and with apical segment modified into a complex flabellate or plumose organ in males-palporgan. *Tarsi 5-5-5 with legs slender, moderately long. *Hind-leg coxae extending laterally to meet the elytra (''Lymexylon''), or not markedly extended laterally (''Elateroides''). *Elytra individually tapered to their apices to not individually tapered; fairly short, exposing several terminal abdominal 1-3 tergites; all articulated and moveable. *Wings with fairly complete venation, radial cell short or absent. Immature Morphology: *Whitish-yellow, elongate, thin, cylindrical with short but well developed legs. *Prognathous, stemmata absent or present may have eye spots. *Abdominal modifications found in older larvae.

Classification

The superfamily Lymexyloidea is currently within

series Series may refer to: People with the name * Caroline Series (born 1951), English mathematician, daughter of George Series * George Series (1920–1995), English physicist Arts, entertainment, and media Music * Series, the ordered sets used in ...

Cucujoidea. The internal phylogeny has not been clearly understood/completed by experts. Morphological data places the family inside the Tenebrionoidea, while molecular data place it as

sister taxon In phylogenetics, a sister group or sister taxon, also called an adelphotaxon, comprises the closest relative(s) of another given unit in an evolutionary tree. Definition The expression is most easily illustrated by a cladogram: Taxon A and t ...

to Tenebrionoidea, and polyphyletic.

Notes

References

* Arnett, Ross H., et al., eds. American Beetles: Polyphaga: Scarabaeoidea through Curculionoidea. Vol. 2. CRC Press, 2002: 261-262. EBSCO printed on Sept. 21,2013. * Casari, S.A. and Albertoni, F.F., (2013). First Instar Larva of ''Atractocerus brasiliensis'' (Lepeletier & Audinet-Serville, 1825) (Lymexylidae, Atractocerinae). Volume 53(27): 359‑372. * Kundrata, R., Bocakova, M., & Bocak, L. (2014). The comprehensive phylogeny of the superfamily Elateroidea (Coleoptera: Elateriformia). Molecular Phylogenetics and Evolution, 76, 162-171. * Triplehorn, Charles A., Norman F. Johnson, and Donald J. Borror. Borror and DeLong's Introduction to the Study of Insects. Belmont, CA: Thompson Brooks/Cole, 2005. * Wheeler, Q. D. (1986). Revision of the genera of Lymexylidae (Coleoptera: Cucujiformia). Bulletin of the American Museum of Natural History, 183:113-210.

External links

* L. Watson and M. J. Dallwitz
Lymexylidae

Lymexylidae on ITISA video of ''Atractocerus brasiliensis'', a ship timber beetle in Costa Rica
{{Taxonbar, from=Q749983 Beetle families Woodboring beetles Articles containing video clips