Leptothorax scamni

Leptothorax scamni
Scientific classification
Kingdom:	Animalia
Phylum:	Arthropoda
Class:	Insecta
Order:	Hymenoptera
Family:	Formicidae
Subfamily:	Myrmicinae
Tribe:	Crematogastrini
Genus:	Leptothorax
Species:	L. scamni
Binomial name
Leptothorax scamni Ruzsky, 1905

Complete colonies, solitary queens, and groups of founding queens were collected in a coniferous forest on a south exposed slope below the Abastumani Astrophysical Observatory, Samtskhe-Javakheti region, Georgia (N:41045.4730, E: 042049.0440, elev. appr. 1535 m) in August 2010 and September 2013. Quite unusual for Leptothorax, colonies nested under the bark on the southern side of stems of Caucasian firs (Abies nordmanniana) and Oriental spruce (Picea orientalis) up to 1.6 m above the ground. Many nests were found near old, withered, injured stem areas, where resin had been tapped, and some colonies were completely surrounded by dry resin deposits. Six colonies were also found in rotting logs and tree stumps on the ground, the typical nest site of other species of Leptothorax. (Heinze and Gratiashvili 2015)

Identification

Heinze, Schulz & Radchenko (1993) - As Ruzsky (1905) clearly mentioned in the original description, the most distinctive characters of L. scamni are the extraordinarily long, finger-shaped propodeal spines in both female castes. Only in Leptothorax acervorum and in an as yet undescribed nearctic Leptothorax sp. A are the spines as long. However, in those species the spines are acutely tapering, not rod-shaped. In addition, L. scamni differs from holarctic L. acervorum in the lack of erect, stiff hairs on scapes and legs and by its notched clypeus. From nearctic Leptothorax sp. A, L. scamni differs in the shapes of the petiole in lateral view and of the postpetiole in dorsal view. In Leptothorax sp. A, the ventral petiolar process is very pronounced and drop-shaped and the postpetiole as seen from above is distinctly trapezoidal.

Keys including this Species

• Key to Palaearctic Leptothorax and Formicoxenus

Distribution

Latitudinal Distribution Pattern

Latitudinal Range: 41.76° to 41.65°.

North Temperate	North Subtropical	Tropical	South Subtropical	South Temperate

• Source: AntMaps, Seifert (2023)

Distribution based on Regional Taxon Lists

Palaearctic Region: Armenia, Georgia, Russian Federation, Türkiye.

Distribution based on AntMaps

Distribution based on AntWeb specimens

Check data from AntWeb

Countries Occupied

Number of countries occupied by this species based on AntWiki Regional Taxon Lists. In general, fewer countries occupied indicates a narrower range, while more countries indicates a more widespread species.

Estimated Abundance

Relative abundance based on number of AntMaps records per species (this species within the purple bar). Fewer records (to the left) indicates a less abundant/encountered species while more records (to the right) indicates more abundant/encountered species.

Biology

Heinze and Gratiashvili (2015) - In August 2010 and September 2013 we collected colonies of L. scamni at its type locality in Abastumani, Georgia. In total we found seven solitary queens, two colonies consisting of five and six queens and one or four workers with a few larvae, and 32 larger colonies (5 queenless, 11 with a single queen, 18 with multiple—2 to 13—dealate female sexuals or queens of unknown reproductive status).

Dissections of queens from collected colonies showed colonies were functionally monogynous. Each examined colony contained only a single physogastric queen with maturing oocytes in its ovaries. Other mated or unmated queens had short ovarioles without maturing viable eggs, though some ovaries contained trophic eggs with large yolky droplets. Similar to other functionally monogynous Leptothorax, the contribution of nestmate queens to the brood is, therefore, highly skewed.

In the laboratory, males and young queens of L. scamni showed sexual activity early in the morning and mated without much flight activity.

Our fieldwork supports the earlier impression that L. scamni is rather patchily distributed. Despite intensive search in other areas around Abastumani, we found colonies only on a south-exposed slope in an open spruce forest.

In contrast to other Leptothorax species, which live at the base of pine trees or in rotting branches (e.g., Buschinger 1968a; Seifert 2007), L. scamni nested under the bark of spruce and fir trees and many nests were surrounded by large deposits of dry resin.

Nomenclature

The following information is derived from Barry Bolton's Online Catalogue of the Ants of the World.

• scamni. Leptothorax (Mychothorax) muscorum var. scamni Ruzsky, 1905b: 620, fig. 151 (w.) CAUCASUS. Heinze, Schulz & Radchenko, 1993: 180 (q.). Raised to species: Arnol'di, 1977a: 204.

Unless otherwise noted the text for the remainder of this section is reported from the publication that includes the original description.

Description

Worker

Heinze, Schulz & Radchenko (1993) - Neotype. Total length appr. 3.5 mm, head length (excluding mandibles) 0.81, head width (behind eyes) 0.71, scape length 0.56, maximum eye diameter 0.15, thorax length (diagonal) 1.06, thorax width 0.46, length of petiole in lateral view 0.38, height of petiole at node in lateral view 0.28, maximum width of petiole 0.19, length of postpetiole in lateral view 0.24, height of postpetiole 0.25, maximum width of postpetiole 0.27, length of hind femur 0.63, length of hind tibia 0.51. Antennae 11-segmented with a 3-jointed apical club. Clypeus deeply notched. Promesonotal suture very distinct, but appearing only slightly impressed in side view. Propodeal spines long, rod-shaped, distal part slightly curved with a blunt tip. Propodeal spine index (Buschinger 1966) appr. 2.0. Head, thorax, petiole, and postpetiole with fine punctulation, head with shallow rugae in addition. Head and gaster dark brown, thorax, petiole, postpetiole, scapes and legs yellowish-brown.

Specimens collected at Giirgentepe Gecidi (Ordu prov., northern Turkey) and material from various areas in the Caucasus closely resemble the neotype. Workers from Artvin (northeastern Turkey) differ in that their propodeal spines are more acute, the ventral petiolar process is more pronounced, and the promesonotal suture is less strongly impressed. Size measurements of material from the Caucasus vary as follows: head length 0.80-0.90 mm, head width 0.67-0.74, scape length 0.56-0.60, thorax length 1.06-1.19.

Queen

Heinze, Schulz & Radchenko (1993) - Dealate queen from Yenicaga Golu, Bolu prov., northern Turkey Total length appr. 4.1 mm, head length 0.86, head width 0.74, scape length 0.58, maximum eye diameter 0.21, thorax length 1.32, maximal width of thorax 0.62, length of petiole 0.38, height of petiole 0.44, width of petiole 0.20, length of postpetiole 0.28, height of postpetiole 0.28, width of postpetiole 0.34, length of hind femur 0.76, length of hind tibia 0.58.

The habitus of the neotype queen is similar to that of queens of other Leptothorax (s. str.). Antennae 11-segmented with a 3-jointed apical club. Mandibles with six teeth. Three ocelli present. Anterior border of clypeus with a distinct notch as in [Leptothorax gredleri|Leptothorax gredleri]] or Leptothorax retractus. Propodeal spines very long, rod-like, with a blunt tip; propodeal spine index appr. 1.9. In lateral view, petiolar node flat, grading smoothly into the weakly convex posterior surface, but separated from the concave anterior surface by a right angle. Postpetiole in dorsal view slightly trapezoidal, in lateral view with a small, sharp ventral tooth. Head, pronotum and scutum rugulose with interrugal spaces punctulate, rest of thorax, petiole and postpetiole finely punctulate, gaster smooth and shining. Body covered with long, erect or suberect hairs, legs and scapes with moderately abundant appressed hairs. Coloration a light brown, dorsal parts of thorax and gaster darker brown.

Type Material

Heinze, Schulz & Radchenko (1993) - Neotype: Worker from Shuntuck, Maykop distr. (northern Caucasus: Adygey Aut. Oblast, Russia), Nr. A 6008 (leg. K. Arnol'di, without date), deposited at the ZMUM (Zoological Museum of Moscow State University, Moscow, Russia.)

Disposition of types - The neotype worker is deposited in the ZMUM (Nr. A 6008). In this collection, several additional specimens of L. scamni were identified. A queen from Yeniqaga Golu (Bolu prov., northern Turkey) and a worker from Gurgentepe Geqidi (Ordu prov., northern Turkey) are deposited in the MCZ. Two workers are in the collection of the MHNG.

References

• Arnol'di, K. V. 1977a. New and little known ant species of the genus Leptothorax Mayr (Hymenoptera, Formicidae) in the European USSR and the Caucasus. Entomol. Obozr. 56: 198-204 (page 204, Raised to species)
• Borowiec, L. 2014. Catalogue of ants of Europe, the Mediterranean Basin and adjacent regions (Hymenoptera: Formicidae). Genus (Wroclaw) 25(1-2): 1-340.
• Dubovikoff, D.A., Yusupov, Z.M. 2017. Family Formicidae - Ants. In Belokobylskij S. A. and A. S. Lelej: Annotated catalogue of the Hymenoptera of Russia. Proceedingss of the Zoological Institute of the Russian Academy of Sciences 6: 197-210.
• Heinze, J. and N. Gratiashvili. 2015. High skew in the Caucasus: functional monogyny in the ant Leptothorax scamni. Insectes Sociaux. 62:385-392. doi:10.1007/s00040-015-0415-5
• Heinze, J.; Schulz, A.; Radchenko, A. G. 1993. Redescription of the ant Leptothorax (s. str.) scamni Ruzsky, 1905. Psyche (Camb.) 100: 177-183. (page 180, queen described)
• Kiran, K., Karaman, C. 2020. Additions to the ant fauna of Turkey (Hymenoptera, Formicidae). Zoosystema 42(18), 285-329 (doi:10.5252/zoosystema2020v42a18).
• Kiran, K., Karaman, C., Heinze, J. 2021. First record of the inquiline ant Leptothorax kutteri Buschinger, 1965 from Turkey. Sociobiology 68, e7224 (doi:10.13102/sociobiology.v68i3.7224).
• Lapeva-Gjonova, A., Kiran, K. 2012. Ant fauna (Hymenoptera, Formicidae) of Strandzha (Istranca) Mountain and adjacent Black Sea coast. North-Western Journal of Zoology 8(1), 72-84.
• Ruzsky, M. 1905b. The ants of Russia. (Formicariae Imperii Rossici). Systematics, geography and data on the biology of Russian ants. Part I. Tr. Obshch. Estestvoispyt. Imp. Kazan. Univ. 38(4-6 6: 1-800 (page 620, fig. 151 worker described)
• Seifert, B. 2023. Two new species of Formicoxenus Mayr 1855 and Leptothorax Mayr 1855 from Tibet (Hymenoptera: Formicidae). Soil Organisms 95(2), 129-142 (doi:10.25674/SO95ISS2ID315).
• Yusupov, Z.M. 2014. Two ant species (Hymenoptera, Formicidae) from the Northern Caucasus, new to the fauna of Russia. Entomological Review 94, 286–287 (doi:10.1134/s0013873814020195).

References based on Global Ant Biodiversity Informatics

• Borowiec L. 2014. Catalogue of ants of Europe, the Mediterranean Basin and adjacent regions (Hymenoptera: Formicidae). Genus (Wroclaw) 25(1-2): 1-340.
• Dubovikoff D. A., and Z. M. Yusupov. 2018. Family Formicidae - Ants. In Belokobylskij S. A. and A. S. Lelej: Annotated catalogue of the Hymenoptera of Russia. Proceedingss of the Zoological Institute of the Russian Academy of Sciences 6: 197-210.
• Gratiashvili N., Barjadze S. 2008. Checklist of the ants (Formicidae Latreille, 1809) of Georgia. Proceedings of the Institute of Zoology (Tbilisi) 23: 130-146.
• Heinze J., A. Schulz, A. G.Radchenko. 1993. Redescription of the ant Leptothorax (s. str.) scamni Ruzsky, 1905. Psyche (Cambridge) 100: 177-183.
• Kiran K., and C. Karaman. 2012. First annotated checklist of the ant fauna of Turkey (Hymenoptera: Formicidae). Zootaxa 3548: 1-38.