Research Article |
Corresponding author: Aleksandr P. Evsyukov ( aevsukov@mail.ru ) Academic editor: Pavel Stoev
© 2021 Aleksandr P. Evsyukov, Sergei I. Golovatch, Dragan Ž. Antić.
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:
Evsyukov AP, Golovatch SI, Antić DŽ (2021) The millipede genera Amblyiulus Silvestri, 1896 and Syrioiulus Verhoeff, 1914 in the Caucasus, with notes on their distributions (Diplopoda, Julida, Julidae). ZooKeys 1048: 109-143. https://doi.org/10.3897/zookeys.1048.68454
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In the Caucasus, the genera Amblyiulus Silvestri, 1896 and Syrioiulus Verhoeff, 1914 are shown to include two and four species, respectively: Amblyiulus georgicus Lohmander, 1932, from Georgia and Armenia, A. hirtus sp. nov., from Azerbaijan and Dagestan, Russia, Syrioiulus adsharicus (Lohmander, 1936), from Georgia, S. continentalis (Attems, 1903), from Azerbaijan and Iran, S. taliscius (Attems, 1927), from Azerbaijan, and S. armeniacus sp. nov., from Armenia. All these six species are described, illustrated, and keyed, and their distributions are mapped and discussed, based on the literature data and abundant new samples.
Faunistic records, key, map, new species, Pachyiulinae, Pachyiulini, taxonomy
The very large family Julidae, of the basically Holarctic order Julida dominates the millipede faunas of Europe and the Mediterranean, marginally extending into the Oriental realm as well (
The genus Pachyiulus Berlese, 1883 contains ca. 15 species of mostly very large julids which are largely confined to Southern and Southeastern Europe, the Near East, and the Caucasus (
The remaining two known genera of this tribe/subfamily which inhabit the Caucasus are Amblyiulus Silvestri, 1896 and Syrioiulus Verhoeff, 1914. The diagnoses and species compositions of these two genera, the main focus of the present contribution, remained unclear and confused for a long time, sometimes the latter genus being treated even as a synonym of the former (
The situation has become fully clarified only very recently, when first
Considering the above distinctions, Amblyiulus in the Caucasus appears to comprise only one described species: A. georgicus Lohmander, 1932. In addition, both
All material has been shared between the collections of the Zoological Museum of the Moscow State University, Russia (
The distribution map was created using Google Earth Pro 7.3.3 and processed in Adobe Photoshop CS6.
A “body ring formula” indicates the number of podous (including the gonopod-bearing segment/ring) and apodous segments/rings in an individual. This formula is p+a+T where p is the number of podous body rings, a the number of apodous body rings, and T represents the telson (
The biogeographic regionalisation of the Caucasus follows the botanical one by
No type material of the previously described species has been revised (mostly stored in the Zoological Institute, Russian Academy of Sciences, St. Petersburg) because of the 2020–2021 COVID pandemic, and the descriptive accounts and illustrations available in the literature are sufficiently complete and clear to allow a safe species identification. Colouration is largely described from preserved material. In the catalogue sections, D stands for a description or descriptive notes, R for new or repeated records, while M is a mere mention.
As shown below in the descriptions of individual species, the use of SEM allows for the distinctions between both genera concerned to be further refined. It is the opisthomere, not the entire posterior gonopod, that is bifid in Syrioiulus: a solenomere (with a distinct fovea or a deep saddle-like structure on top) and an anterior process (an anterior, lamellar branch adjacent to the solenomere) (Figs
As a result, it is only the structure of the opisthomere of the posterior gonopods that allows for the genera Amblyiulus and Syrioiulus to be more or less confidently diagnosed and separated. At the same time, species of Syrioiulus are mostly very similar in gonopodal conformation (Figs
Julus barroisi Porat, 1893, by original designation.
Here we follow
The promere in Amblyiulus is narrowed in the basal third, in contrast to that in Promeritoconus, which is narrowed apically; in the apical part it may have one or two denticles, but sometimes none. The head can be with or without frontal setae. The eyes are mostly absent. The opisthomere of the posterior gonopod is tripartite: a solenomere, an anterior process, and an anteromesal or lateral rod, vs. bipartite in Syrioiulus.
Amblyiulus barroisi (Porat, 1893), Amblyiulus cedrophilus (Attems, 1910), Amblyiulus festae (Silvestri, 1895), Amblyiulus georgicus Lohmander, 1932, Amblyiulus hirtus sp. nov., and possibly several others, but their identity requires verification (
Amblyiulus georgicus Lohmander, 1932a: 180–182, figs 10–12 (D).
Amblyiulus georgicus
—
Syrioiulus georgicus
—
Armenia: 3 ♂♂, 5 ♀♀, 2 juv. (
Differs from A. hirtus sp. nov., apparently the most similar and geographically the closest congener known to date, by the following combination of somatic and gonopodal characteristics. Head without frontal setae; collum and metazonae of body rings without setae. Male mandibular stipites expanded. Promere wide, with two apical denticles. Solenomere with a membranous lobe notched apically. Rod of opisthomere relatively short. See also Key below.
Length of adults 27–30 mm (♂♂) or 28–31 mm (♀♀), width 1.6–1.7 mm (♂♂) or 1.7–1.9 mm (♀♀). Number of body rings in adults, 65–67+2+T (♂♂) or 67–69+2+T (♀♀). Body subcylindrical (typical of Julidae), metazonae brownish grey, prozonae yellowish grey (Fig.
Habitus of Amblyiulus and Syrioiulus species, males, lateral views A A. georgicus Lohmander, 1932 from Shnokh, Armenia (
Antennae relatively long, in situ reaching segment 4. Head without frontal setae, but with 8+8–9+9 labral and 2+2 supralabral setae (Fig.
Amblyiulus georgicus Lohmander, 1932, ♂ from Shnokh, Armenia (
Male. Mandibular stipites expanded, slightly swollen in distal part (Fig.
Gonopods (Fig.
Amblyiulus georgicus Lohmander, 1932, ♂ from Shnokh, Armenia (
Female. First two leg pairs unmodified. Vulva rounded, operculum and bursa equal in height (Fig.
This species was described from Borjom (= Borjomi), Georgia (
Holotype
♂ (
Azerbaijan: 2 ♂♂, 6 ♀♀ (
Assigned to the genus Amblyiulus primarily because of the presence of a rod on the posterior gonopod opisthomere. Differs from A. georgicus, perhaps the most similar congener known to date, by the following combination of somatic and gonopodal characters. Head with frontal setae; collum and metazonae of body rings each with a posterior whorl of setae. Promere narrow, with two side ridges. Solenomere apically with small filament-like processes. Rod of opisthomere relatively long.
To emphasise the presence of metazonal setae; adjective.
Holotype
: length 27 mm, width 1.3 mm, number of body rings 51+2+T. Paratypes: length 25–30 mm, width 1.2–1.4 mm, number of body rings in adults, 45–67+1–3+T (♂♂); or length 27–28 mm, width 1.1–1.3 mm, number of body rings, 46–55+2–3+T (♀♀). Body subcylindrical (typical of Julidae), metazonae and prozonae yellowish grey (Fig.
Amblyiulus hirtus sp. nov., paratype ♂ from Bash-Layski, Azerbaijan (
Antennae relatively long, in situ reaching ring 4. Head with 1+1 frontal, 8+8–9+9 labral and 2+2 supralabral setae (Fig.
Male. Mandibular stipites unmodified (Fig.
Gonopods (Fig.
Amblyiulus hirtus sp. nov., paratype ♂ from Bash-Layski, Azerbaijan (
Female. First two leg pairs unmodified. Vulva rounded, operculum higher than bursa (Fig.
This species seems to be endemic to the eastern part of the Caucasus Major within both northeastern Azerbaijan and the Republic of Dagestan, Russia (Fig.
It is the presence of a laterally positioned rod that brings both A. georgicus and A. hirtus sp. nov. particularly close together. However, the rod in these two species is located laterally, whereas that in A. barroisi anteromesally (
Dolichoiulus polyzonus Attems, 1910, by subsequent designation of
All characters as in Amblyiulus, except as follows. Promere usually with two denticles in apical part. Head with or without frontal setae. Eyes present or absent. Opisthomere of posterior gonopod bipartite: a solenomere (with a distinct fovea on top) and an anterior process, vs. tripartite in Amblyiulus.
Syrioiulus adsharicus (Lohmander, 1936), Syrioiulus andreevi Mauriès, 1984, Syrioiulus aharonii (Verhoeff, 1914), Syrioiulus armeniacus sp. nov., Syrioiulus continentalis (Attems, 1903), Syrioiulus discolor (Lohmander, 1932), Syrioiulus incarnatus (Lohmander, 1932), Syrioiulus lohmanderi Vagalinski, 2020, Syrioiulus persicus (Golovatch, 1983), Syrioiulus polyzonus (Attems, 1910), Syrioiulus taliscius (Attems, 1927), and several others provisionally listed by
Amblyiulus (Heteropachyiulus) adsharicus Lohmander, 1936: 156–159, figs 131, 132 (D).
Amblyiulus adsharicus
—
Syrioiulus adsharicus
—
Georgia: 10 ♂♂, 16 ♀♀, 5 juv. (
Differs from all congeners by the following combination of somatic and gonopodal characters. Head with frontal setae. Collum and each metazona of following body rings with a whorl of long setae at caudal margin. Ommatidia present, but only a few ommatidia, all unpigmented and very small. Solenomere with small denticles apically. Anterior process of opisthomere with small filament-like spines apically.
Length of adults 17–30 mm (♂♂) or 18–31 mm (♀♀), width 1.2–1.4 mm (♂♂) or 1.3–1.7 mm (♀♀). Number of body rings in adults, 50–63+1–2+T (♂♂) or 52–60+1–2+T (♀♀). Body subcylindrical (typical of Julidae), metazonae brownish grey, prozonae violet grey (Figs
Syrioiulus adsharicus (Lohmander, 1936), ♂ from Adigeni, Georgia (
Antennae relatively long, in situ reaching segment 4. Head with 1+1 frontal, 11+11–13+13 labral and 2+2 supralabral setae (Fig.
Male. Mandibular stipites expanded, slightly swollen (Fig.
Gonopods (Fig.
Syrioiulus adsharicus (Lohmander, 1936), ♂ from Adigeni, Georgia (
Female. First two leg pairs unmodified. Vulva elongated, covered with long setae (Fig.
This species was originally described from Batumi, “Bortschacha” (
Pachyiulus (Dolichoiulus) continentalis Attems, 1903: 147, 148, figs 82–84 (D).
Amblyiulus continentalis
—
Syrioiulus continentalis
—
Azerbaijan: 3 ♂♂, 1 ♀ (
Differs from all congeners by the following combination of somatic and gonopodal characters. Head with frontal setae. Collum and each metazona of following body rings with a whorl of long setae at caudal margin. Eyes present. Solenomere with a group of small spines on top. Anterior process of opisthomere subtriangular apically. This species is clearly distinguished in the field from all other millipedes by its characteristic greyish yellow colouration with a yellow stripe dorsally, and its particularly strong odour clearly resembling that of Pachyiulus krivolutskyi from the western Caucasus (= Colchis).
Length of adults 28–45 mm (♂♂) or 26–46 mm (♀♀), width 2.0–2.3 mm (♂♂) or 2.2–2.7 mm (♀♀). Number of body rings in adults, 46–66+1–2+T (♂♂) or 49–66+1–2+T (♀♀). Body subcylindrical, metazonae from greyish yellow to yellow, prozonae light yellow (Figs
Antennae relatively long, in situ reaching segment 3. Head with 1+1 frontal, 8+8–9+9 labral and 2+2–4+4 supralabral setae (Fig.
Syrioiulus continentalis (Attems, 1903), ♂ from Istisu, Azerbaijan (
Male. Mandibular stipites expanded, with swollen lobes (Fig.
Gonopods (Fig.
Syrioiulus continentalis (Attems, 1903), ♂ from Hyrcan Nature Reserve (A–C) (
Female. First two leg pairs unmodified. Operculum of vulva without setae on caudal surface, apical margin relatively flat (Fig.
Probably one of the most common and apparently the largest species of the genus. The unusually strong odour and the chemical composition of the repugnatorial secretion are similar to those of Pachyiulus krivolutskyi (Makarov et al., pers. obs.). This species inhabits various deciduous forests in Azerbaijan, also occurring in northern Iran (
Amblyiulus taliscius Attems, 1927: 243, 244, figs 336–338 (D).
Amblyiulus taliscius
—
Syrioiulus taliscius
—
Azerbaijan: 4 ♂♂, 14 ♀♀, 1 juv. (
Differs from all congeners by the following combination of somatic and gonopodal characters. Head without frontal setae. Collum and metazonae of following body rings without setae. Eyes absent. Solenomere in apical part with a group of small spines. Anterior process of opisthomere subtriangular apically.
Length of adults 26–33 mm (♂♂) or 26–34 mm (♀♀), width 1.2–1.3 mm (♂♂) or 1.2–1.4 mm (♀♀). Number of body rings in adults, 50–65+1–2+T (♂♂) or 49–70+1–2+T (♀♀). Body subcylindrical (typical of Julidae), live specimens with brownish grey pro- and metazonae (Fig.
Syrioiulus taliscius (Attems, 1927), ♂ from Avrora, Azerbaijan (
Antennae relatively long, in situ reaching segment 3. Head without frontal setae, 9+9–12+12 labral and 2+2 supralabral setae (Fig.
Male. Mandibular stipites unmodified (Fig.
Gonopods (Fig.
Syrioiulus taliscius (Attems, 1927), ♂ from Hyrcan Nature Reserve (A–C) (
Female. First two leg pairs unmodified. Operculum of vulva without setae on caudal surface, apical margin poorly divided (Fig.
This species was described from the Talysh Mts, Lenkoran, Azerbaijan (
Holotype
♂ (
Armenia: 4 ♂♂, 3 ♀♀ (
This new species belongs to the genus Syrioiulus because of the presence of only two apices on the opisthomere. Differs from all regional congeners by the following combination of somatic and gonopodal characters. Head with frontal setae. Collum and metazonae of following body rings without setae. Eyes absent. Solenomere with a pointed process apically. Anterior process rounded on top.
The new species is named after its terra typica; adjective.
Holotype: length 25 mm, width 1.2 mm, number of body rings 50+2+T. Paratypes and non-type material: length 17–33 mm, width 1.2–1.6 mm, number of body rings, 50–68+1–2+T (♂♂); or length 20–29 mm, width 1.2–1.6 mm, number of body rings, 46–55+2–3+T (♀♀). Body subcylindrical, metazonae brownish yellow, prozonae brownish grey (Figs
Syrioiulus armeniacus sp. nov., paratype ♂ from Shikahoh, Armenia (
Antennae relatively long, in situ reaching segment 3. Head with 1+1 frontal, 9+9–10+10 labral and 2+2 supralabral setae (Fig.
Male. Mandibular stipites modified, slightly swollen in distal part (Fig.
Gonopods (Fig.
Syrioiulus armeniacus sp. nov., paratype ♂ from Shikahoh, Armenia (
Female. First two leg pairs unmodified. Vulva rounded, operculum higher than bursa (Fig.
Vulvae of Amblyiulus and Syrioiulus species from the Caucasus, caudal views A A. georgicus Lohmander, 1932 from Shnokh, Armenia (
This species seems to be endemic to the Caucasus Minor within Armenia, but most likely it also occurs in the adjacent parts of eastern Azerbaijan and northwestern Iran (Fig.
Distributions of Amblyiulus and Syrioiulus species in the Caucasus: red circle A. georgicus Lohmander, 1932; green circle A. hirtus sp. nov.; white circle S. adsharicus (Lohmander, 1936); blue circle S. continentalis (Attems, 1903); pink circle S. taliscius (Attems, 1927); brown circle S. armeniacus sp. nov.; yellow square Pachyiulini gen. sp. 1; purple square Pachyiulini gen. sp. 2.
1 ♀ (
Body grey, head and collum dark yellow, antennae and legs yellow. The following somatic characteristics seem to be the most important: absence of eyes, presence of frontal setae, presence of caudal whorls of setae on metazonae, absence of an epiproct, and setose anal valves.
Unfortunately, the only female does not allow a closer generic allocation.
Georgia: 1 ♀ (
Body greyish yellow. Head, collum, a few postcollum rings and telson slightly lighter than other body rings. Ommatidia and frontal setae absent. Collum and each metazona of following rings with a whorl of long setae at posterior margin. Epiproct undeveloped. Anal valves densely setose.
These specimens differ from Syrioiulus adsharicus in the absence of frontal setae and ommatidia. The absence of males makes it impossible to definitively identify the above samples. At least the taxonomic significance of frontal setae must not be overestimated, as they may be present or absent even within the same species, e.g., S. aharonii (see
Since the two unidentified species may well prove to represent Amblyiulus or Syrioiulus, we map their records in Figure
1 | Opisthomere of gonopod with a rod (Fig. |
(genus Amblyiulus) 2 |
– | Opisthomere of gonopod without rod | (genus Syrioiulus) 3 |
2 | Head without frontal setae, collum and metazonae of body rings without setae (Fig. |
A. georgicus |
– | Head with 1+1 frontal setae, collum and metazonae of body rings with whorls of setae at caudal margin (Fig. |
A. hirtus sp. nov. |
3 | Eyes present | 4 |
– | Eyes absent | 5 |
4 | Larger: width > 2.0 mm. Eyes well-developed, black, oval, each composed of 19–23 ommatidia (Fig. |
S. continentalis |
– | Smaller: width < 1.3 mm. Eyes present, but very small and unpigmented, each composed of 3–7 ommatidia (Fig. |
S. adsharicus |
5 | Head without frontal setae (Fig. |
S. taliscius |
– | Head with 1+1 frontal setae (Fig. |
S. armeniacus sp. nov. |
Two allopatric species of Amblyiulus, both likely endemic, are found to populate the Caucasus. Amblyiulus georgicus inhabits western and central Transcaucasia, while A. hirtus sp. nov. seems to be confined to northeastern Transcaucasia and the eastern Caucasus, i.e., occurring on both macro slopes of the Caucasus Major (Fig.
The genus Syrioiulus is more diverse and widespread, but presently it seems to be restricted to Transcaucasia. Thus, S. adsharicus has a rather narrow distribution in the southwestern parts of the Colchidan biogeographic province. Two most widespread species, S. continentalis and S. taliscius, are often sympatric to even syntopic within the Hyrcanian biogeographic province, but the latter species also occurs in the Caucasus Minor and the eastern part of the Caucasus Major. Syrioiulus armeniacus sp. nov. inhabits the Caucasus Minor within southern and central Transcaucasia (Fig.
As regards the vertical distributions, most species of Amblyiulus and Syrioiulus in the Caucasus are confined to montane forests, as are probably all Syrioiulus species known from Hyrcania, including the Iranian S. astrabadensis (Lohmander, 1932b), S. discolor (Lohmander, 1932b), S. incarnatus (Lohmander, 1932b), S. lohmanderi Vagalinski, 2020, S. persicus (Golovatch, 1983) and S. zarudnyi (Lohmander, 1932b) (
Only two species of Syrioiulus, S. continentalis and S. taliscius, are endemic or subendemic, respectively, to the Hyrcanian biogeographic province within the Republic of Azerbaijan and Iran, while the remaining Amblyiulus and Syrioiulus spp., however provisionally, are formally strictly endemic to the Caucasus sensu lato, including Hyrcania (Fig.
Both unidentified species seem to be endemic to the Caucasus, with Pachyiulini gen. sp. 1 being confined to Ciscaucasia, and Pachyiulini gen. sp. 2 to deciduous forests in southern Colchis, occurring sympatrically with Syrioiulus adsharicus (Fig.
The above picture is definitely very far from final, but it agrees well with the biogeography of the Caucasus (e.g.,
We are most grateful to all collectors who rendered us their material for treatment. We are also greatly obliged to both Igor Zabiyaka (Don StateTechnical University, Rostov-on-Don, Russia) for taking SEM pictures. DA is grateful to Hans Reip and Frank Walther (both Germany) for their help during the field trip in Azerbaijan in March 2015, as well as again to Hans Reip and Karin Voigtländer (Germany) for their help in the preparation of some samples used here for SEM. AE was supported by RFBR, Project No. 20-54-18008, SG by the Presidium of the Russian Academy of Sciences, Programme No. 41 “Biodiversity of Natural Systems and Biological Resources of Russia”, while DA by the project “Biogeography of the land molluscs of the Caucasus region” funded by VolkswagenStiftung, and the Serbian Ministry of Education, Science, and Technology (Grant 173038) for making his field trip to Azerbaijan possible, as well as by the SYNTHESYS Project (DE-TAF-5619) financed by European Community Research Infrastructure Action under the FP7 “Capacities” Program which allowed him short visits to the Senckenberg Museum of Natural History in Görlitz (Germany) in 2016. We are most thankful to Henrik Enghoff (Copenhagen, Denmark) and Boyan Vagalinski (Sofia, Bulgaria), the reviewers who provided constructive criticism and thus considerably improved our paper. Pavel Stoev (Sofia, Bulgaria) very helpfully served as the managing editor.