Research Article |
Corresponding author: Dragan Antić ( dragan.antic@bio.bg.ac.rs ) Academic editor: Nesrine Akkari
© 2018 Dragan Antić, Boyan Vagalinski, Pavel Stoev, Sergei Golovatch.
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:
Antić D, Vagalinski B, Stoev P, Golovatch S (2018) Two new species of the millipede genus Metonomastus Attems, 1937 from the Balkan Peninsula (Diplopoda, Polydesmida, Paradoxosomatidae). ZooKeys 786: 43-57. https://doi.org/10.3897/zookeys.786.28386
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In addition to the eleven previously known species of the Mediterranean genus Metonomastus, two more species are described: M. petrovi sp. n., from the Rhodopi Mts. and Bunardzhik Hill in Bulgaria, and M. radjai sp. n., from the island of Mljet in Croatia. The relationships between the congeners and their distributions are briefly discussed. All 13 species of the genus are keyed.
Bulgaria, cave, Croatia, Dinarides, island, millipede, Rhodopes, taxonomy
In the latest taxonomic survey of the genus Metonomastus Attems, 1937,
The present paper is devoted to descriptions of two new species of Metonomastus found in the Rhodopi Mountains and Bunardzhik Hill in Bulgaria and the Dinaric island of Mljet in Croatia.
Specimens preserved in 70% ethanol were examined with Nikon SMZ 745T and Zeiss Stemi 2000-C binocular stereo microscopes. All taxonomically important structures were dissected and mounted in glycerine as temporary microscopic preparations and observed with a Carl Zeiss Axioscope 40 and an Olympus BX51 light microscope. Pictures of legs were taken with a Canon PowerShot A80 digital camera connected to the Axioscope 40 microscope, and with an Olympus XC30 digital camera connected to the Olympus BX51 microscope. Line drawings of gonopods were made using tracing paper placed on a computer monitor showing pictures of those structures. Pictures of habitus structures were taken using a Nikon DS-Fi2 camera with a Nikon DS-L3 camera controller attached to a Nikon SMZ 1270 binocular stereo microscope, and with a Nikon Coolpix S3700 attached to one eyepiece of a Carl Zeiss Discovery.V8 binocular stereo microscope. Focal stacking was completed with Zerene Stacker software. Some relevant structures were investigated with JEOL JSM-6460LV (University Centre for Electron Microscopy, Department of Biology and Ecology, University of Novi Sad, Serbia) and JEOL JSM-5510 (Faculty of Chemistry, Sofia University) scanning electron microscopes.
Descriptions of the new taxa largely follow
The final images were processed with Adobe Photoshop CS6.
Abbreviations used to denote gonopodal structures are explained directly in figure captions.
NHMSC Natural History Museum, Split, Croatia
Microdesmus
Verhoeff, 1901: 223; preoccupied, replaced with Metonomastus by
Nannodesmus
Chamberlin, 1943: 35; replacement name for Microdesmus Verhoeff, 1901; synonymized by
Microdesminus
Strasser, 1960: 96; synonymized by
Small (< 10 mm long) moniliform polydesmoids with pale body and 19 segments in both sexes (Figs
Metonomastus albus (Verhoeff, 1901)
M. bosniensis (Verhoeff, 1901)
M. capreae (Verhoeff, 1942)
M. hirtellus (Silvestri, 1903)
M. mariae (Strasser, 1965)
M. patrizii Manfredi, 1950
M. petrelensis Mauriès, Golovatch & Stoev, 1997
M. petrovi sp. n.
M. pomak Golovatch & Stoev, 2004
M. radjai sp. n.
M. romanus (Verhoeff, 1951)
M. saetosus (Strasser, 1960)
M. strasseri Hoffman & Lohmander, 1968
Holotype male (
2 males, 5 females (
2 females, 1 juvenile (
The species is named after Boyan Petrov, a renowned Bulgarian mountaineer, a dear friend and colleague zoologist from the National Museum of Natural History, Sofia, who disappeared in Tibet in May 2018 during the ascent of his 11th eight-thousander, Shishapangma. Boyan was one of the collectors of this new species. Noun in genitive case.
The new species belongs to the Metonomastus group of species with three acropodital branches, but clearly differs from both previously described species in this group, M. strasseri Hoffman & Lohmander, 1968, and M. pomak Golovatch & Stoev, 2004, by the presence of a strongly developed, beak-shaped solenomere, by the completely reduced solenophore and by the development of a strongly arched, microspiculate, ventromesal, acropodital process.
Length 4.4–4.8 mm (males), 4.2–5.5 mm (females). Width of midbody rings 0.31–0.37 and 0.33–0.42 mm (males), 0.35–0.42 and 0.42–0.47 mm (females) on pro- and metazonae, respectively. Holotype male 4.8 mm long, 0.37 and 0.42 mm wide on midbody pro- and metazonae, respectively.
Body moniliform (Figure
Head densely pubescent throughout, clypeolabral region densely setose. In males, width of head (0.41–0.5 mm broad) >> collum ≤ ring 2 ≤ 3 ≥ 4 < 5 ≥ 6 = 17; thereafter body gradually, but significantly tapering. In females, width of head (0.42–0.5 mm broad) >> collum = ring 2 < 3 = 4 < 5 = 17; thereafter body rather rapidly tapering; in larger females, ring 5 = 14 < 15 = 17.
Antennae (Figure
Collum with 3 rows of setae; two rows of similar setae per postcollum metatergum: one frontally, the other caudally, setae long and simple. Metaterga (Figure
Legs (Figure
Gonopods (Figs
This species is known both from caves and from an epigean environment. Like some other representatives of the genus, this new species can be considered a troglophile.
Metonomastus petrovi sp. n. A paratype ♂, left gonopod, ventromesal view B paratype ♂, distal part of left gonopod, ventromesal view C paratype ♂, right gonopod, ventral view D non-type ♂, right gonopod, mesal view E non-type ♂, right gonopod, ventral, slightly lateral view, F non-type ♂, right gonopod, ventromesal process, same view, enlarged. Abbreviations: cx coxite, pf prefemorite, sl solenomere, ss saddle-shaped process, vm ventromesal process. Scale bars: 0.2 mm (B), 0.05 mm (A, C, D, E), 0.005 mm (F).
Holotype male (NHMSC), Croatia, Dalmatia, island of Mljet, Blato, near Kozarica, under stones, 23.XII.2015, T. Rađa leg.
1 male (NHMSC), 2 males (
The new species is named after the collector, Tonći Rađa, a renowned Croatian biospeleologist who discovered numerous new or interesting arthropods. Noun in genitive case.
The new species belongs to the Metonomastus group of species with two postfemoral branches, but clearly differs from all of these by the presence of a well-developed, broad, lamellar solenophore (= tibiotarsus) directed strongly mesad, and proximally curved ventrad. The solenomere is without additional processes and is also directed strongly mesad.
Metonomastus radjai sp. n., paratype ♀ (
Length 3.7–3.9 mm (males), 4.3–5 mm (females). Width of midbody rings 0.30–0.33 and 0.37–0.4 mm (males), 0.42–0.44 and 0.47–0.5 mm (females) on pro- and metazonae, respectively. Holotype male 3.7 mm long, 0.3 and 0.37 mm wide on midbody pro- and metazonae, respectively.
All other characters as in M. petrovi sp. n., except as follows.
Microreticulated texure more obvious (Figs
Gonopods (Figs
This species was found under stones next to a dry stone wall close to the seashore.
Metonomastus radjai sp. n., A, B, C, D paratype ♀ (
Based on gonopod characters, species of Metonomastus may provisionally be divided into two groups. The first group is characterized by a two-branched acropodite, while the second group includes species with three branches. Such a division is also supported biogeographically. Taxa with two acropodital branches appear in the central Mediterranean: in northeastern and central Italy and along the Adriatic coast of the western Balkans. This group contains ten species, including Metonomastus radjai sp. n. Among these congeners, M. capreae (Verhoeff, 1942), M. hirtellus (Silvestri, 1903), M. mariae (Strasser, 1965), M. patrizii Manfredi, 1950, and M. romanus (Verhoeff, 1951) are all known from central Italy [M. hirtellus was recently found also in Croatia (
The second group within Metonomastus includes three species, viz. M. pomak, M. strasseri, and M. petrovi sp. n. All three species are characterized by the presence of three acropodital branches. Unlike the previous, central Mediterranean group, these taxa inhabit the eastern Mediterranean within Greece and northwestern Anatolia (M. strasseri) or the Rhodopian part of Bulgaria (M. pomak and M. petrovi sp. n.). In both previously described species, the solenophore appears as the main, long and curved branch above the solenomere which can be long and slender in M. strasseri or lamelliform and broad in M. pomak. The new species clearly differs from both of them by the presence of a strongly developed, robust and somewhat beak-shaped solenomere which appears as the main branch, while a solenophore is fully reduced.
As already stated by
1 | Metatergal setae absent | M. bosniensis |
– | Metatergal setae present | 2 |
2 | Gonopods with three acropodital branches | 3 |
– | Gonopods with two acropodital branches | 5 |
3 | Solenophore absent | M. petrovi sp. n. |
– | Solenophore present | 4 |
4 | Solenomere lamelliform and broad | M. pomak |
– | Solenomere elongated and slender | M. strasseri |
5 | Metaterga densely setose | M. saetosus |
– | Metaterga with 2–3 rows of setae | 6 |
6 | Gonopod prefemorite suboval and considerably shorter than acropodite | M. albus |
– | Gonopod prefemorite subquadrate and about as long as acropodite | 7 |
7 | Acropodital branches slender and sinuate | M. petrelensis |
– | Acropodital branches stouter | 8 |
8 | Solenomere strongly curved mesad | M. radjai sp. n. |
– | Solenomere not curved mesad, but erect | M. capreae , M. hirtellus , M. mariae , M. patrizii , M. romanus |
We are grateful to Plamen Mitov (Bulgaria) for donating material of M. petrovi sp. n. This study was partly supported by the Serbian Ministry of Education, Science, and Technology (Grant 173038) and by the National Endowment Fund “13 Centuries Bulgaria”. Special thanks to the reviewers Robert Mesibov (Tasmania) and Henrik Enghoff (Denmark), and the editor Nesrine Akkari (Austria) for their helpful commentaries and suggestions which improved the paper.