Arthropod diversity in Iran: Class Diplopoda Blainville in Gervais, 1844

Sergei I. Golovatch

Institute of Ecology and Evolution, Russian Academy of Sciences, Leninsky pr. 33, Moscow 119071 Russia.

https://orcid.org/0000-0001-7159-5484

ABSTRACT. Formally, the diplopod fauna of Iran presently contains 54 species from 27 genera, 13 families and eight orders, all listed and supplied with nomenclature, diversity estimates and known species records. Endemism is profound at the species level (ca 80%), but nearly absent at any higher rank. The only and quite remarkable exception is the genus Chiraziulus, both species of which are endemic to southern or central Iran. The fauna can generally be considered as Caucasian, part of the eastern Mediterranean realm, vs Chiraziulus that clearly represents a very ancient and relict group (suborder Cambalidea) presently occurring in the Nearctic (together with the Hawaiian Islands, Pacific Ocean) in the New World, but rather Oriental, both tropical and subtropical, in Indo-Australasia (together with the Mascarene Islands, Indian Ocean).

Keywords: Faunistic records, Hyrcania, Myriapoda, Near East, Taxonomy

Citation: Golovatch, S.I. (2025) Arthropod diversity in Iran: Class Diplopoda Blainville in Gervais, 1844. Journal of Insect Biodiversity and Systematics, 11 (3), xx–xx.

Millipedes, or Diplopoda, are the largest class of Myriapoda, a group of land arthropods currently encompassing ca 11,000 described species from 2,000+ genera, 140+ families and 16 extant orders, and populating all continents except Antarctica (Enghoff et al., 2015). The bulk of millipede diversity is observed in tropical and subtropical countries, whereas temperate faunas are dominated by fewer orders of Diplopoda, i.e. the mostly Holarctic Glomerida, Julida and Callipodida. Diplopoda are largely meso- to hygrophilous, the detritivores that consume dead plant material and mostly inhabit forest litter and the uppermost soil, albeit the proportions of soil- and, especially, cave-dwellers are also considerable. The main and primary environment for millipedes seems to have always been the forest floor (Golovatch, 1994; Kime & Golovatch, 2000). The largely highly restricted dispersal abilities and the typically poor compensatory ecological capacities, when even one limiting factor cannot be compensated for by others, however favourable, result in millipede species distributions mostly being narrow, and local endemism profound. Thus, the world records of millipede local diversity, or faunules, are only ca 40 species in tropical forest nature reserves in central Amazonia, Brazil and southern Vietnam (Golovatch, 1997; Golovatch et al., 2011).

Taxonomic research on the diplopod fauna of Iran started with the pioneer paper by Humbert & de Saussure (1869) who described the first two species from the country. Further progress had been rather modest and sporadic until Enghoff & Moravvej (2005) compiled the first catalogue of Iranian Diplopoda and listed all faunistic records, both old and new. The catalogue concerned already 50 species. The latest checklist and review (Golovatch et al., 2022) culminated in altogether 55 species, 27 genera, 13 families and eight orders of millipedes being recorded from Iran. Of them, at least 33 species, but not a single higher taxon, have been noted as endemic or subendemic to Hyrcania. Presenting another review of step-by-step faunistic studies on the Diplopoda of Iran hardly makes sense, as all relevant information is contained below per species, both in terms of references and faunistic records. In addition, the distributions are assembled into gross chorotypes (see Table 1), and several species that are formally still absent from the fauna of Iran are pointed out as potential and most likely future records.

The Caucasus as a biogeographic realm of the Palaearctic subregion of the Holarctic has long been known as comprising two mesic biogeographic provinces, one, Colchis (= Colchida), in the west, stranding along the eastern and southeastern coasts of the Black Sea within Russia, Abkhazia, Georgia and Turkey, and the other, Hyrcania, along the southwestern and southern coasts both of the Republic of Azerbaijan and Iran. Both counterpart provinces support ancient meso- to hygrophytic woodlands (Wulff, 1944; Abdurakhmanov, 2017), the habitats preferred by Diplopoda. Both Cholchis and Hyrcania are strongly separated by the montane and much more xeric Caucasus Minor uplands. Hardly surprising, it is Hyrcania that hosts most of Iran’s millipede fauna and endemic species (Golovatch et al., 2022). In contrast, only one genus with two species appears to be endemic to southern and central Iran, well outside its Hyrcanian part.

The present contribution updates and refines the Iranian fauna of Diplopoda and, following Enghoff et al. (2015), it also provides the modern classification of all higher taxa and most of the estimates of their global diversity. Only subfamilies and subgenera have been omitted as being hardly too relevant (cf. Enghoff & Moravvej, 2005; Golovatch et al., 2022).                                        

MATERIAL AND METHODS

The data presented below are derived from all relevant taxonomic and/or faunistic papers pertaining to the millipedes of Iran (see list of references). Two most recent synopses (Enghoff & Moravvej, 2005; Golovatch et al., 2022) served as the basics, whereas the detailed information for the species recorded from Iran has been documented based on original representative sources (Brolemann, 1922; Lohmander, 1932, 1936; Attems, 1927, 1951; Golovatch, 1981, 1983; Mauriès, 1982; Enghoff, 1984, 1990, 1995; Read, 1992; Reboleira et al., 2015; Vagalinski & Lazányi, 2018; Vagalinski, 2020; Vagalinski & Golovatch, 2021), which primarily include the original descriptions and reports of their distribution ranges. The classification and nomenclature are derived from the most recent global treatise on Diplopoda (Enghoff et al., 2015). The number of species, genera, families, suborders, and orders is indicated alongside the name of the primary (parent) taxon. The global statistics for the relevant taxa are specified in brackets.

RESULTS

Taxonomic hierarchy

Phylum: Arthropoda von Siebold, 1848

Subphylum: Myriapoda Latreille, 1802

Class Diplopoda Blainville in Gervais, 1844 – (8[16] orders, 13[140+] families, 27[2,000+] genera, ca 11,000 species).

Subclass Penicillata Latreille, 1831 – (1[1] order, 2[38] genera, 2[ca 150] species).

Order Polyxenida Verhoeff, 1934 – (2[3] families).

Family Lophoproctidae Silvestri, 1897 – (1[5] genera, 1[43] species).

Genus Lophoproctus Pocock, 1894 – (1[4] species).

Family Polyxenidae Lucas, 1840 – (1[22] genera, 1[ca 98] species).

Genus Propolyxenus Latreille, 1802/03 – (1[9] species).

Subclass Chilognatha Latreille, 1802/03 – (7[15] orders, 25[1962+] genera, >10,000 species).

Infraclass Pentazonia Brandt, 1833 – (1[3] orders, 2[ca 675] species).

Order Glomerida Leach, 1814 – (2[3] families, 3[34] genera, 4[300+] species).

Family Glomeridae Leach, 1815 – (2[28] genera, 2[ca 250] species).

Genus Hyleoglomeris Verhoeff, 1910 – (1[100+] species).

Genus Trachysphaera Heller, 1857 – (1[ca 30] species).

Family Glomeridellidae Cook, 1896 – (1[3] genus, 1[25] species).

Genus Typhloglomeris Verhoeff, 1898 – (1[ca 15] species).

Infraclass Helminthomorpha Pocock, 1887 – (12 orders, ca 9,000 species).

Subterclass Colobognatha Brandt, 1834 – (1[4] orders, 1[8] families, 1[240+] species).

Order Platydesmida de Saussure, 1860 – (1[2] families, 1[70+] species).

Family Andrognathidae Cope, 1869 – (1[12] genera, 1[40+] species).

Genus Fioria Silvestri, 1898 – (1[4] species).

Subterclass Eugnatha Attems, 1898 – (3[3] superorders, > 8,700 species).

Superorder Nematophora – (2[3] orders).

Order Callipodida Pocock, 1894 – (1[3] suborders, 2[8] families, 2[36] genera & subgenera, 3[ca 140] species/subspecies).

Family Caspiopetalidae Lohmander, 1931 – (1[1] genus, 2[8] species).

Genus Bollmania Silvestri, 1896 – (2[8] species).

Family Schizopetalidae Verhoeff, 1909 – (1[10] genera, 1[53] species).

Genus Eurygyrus C.L. Koch, 1847 – (1[18] species).

Order Chordeumatida Pocock, 1894 – (1[4] suborders, 1[ca 50] families).

Suborder Craspedosomatidea Cook, 1895 – (1[3] families, 2[48] genera).

Family Anthroleucosomatidae Verhoeff, 1899 – (2[ca 25] genera, 2[70+] species).

Genus Alloiopus Attems, 1951 – (1[1] species).

Genus Metamastigophorophyllon Cauca, 1976 – (1[5] species).

Superorder Juliformia Attems, 1926 – (2[3] orders).

Order Spirostreptida Brandt, 1833 – (1[2] suborders).

Suborder Cambalidea Cook, 1895 – (1[5] families).

Family Cambalidae Bollman, 1893 – (1[ca 40] genera and 2[200+] species).

Genus Chiraziulus Mauriès, 1983 – (2[2] species).

Remarks. This is the only Palaearctic Cambalidea endemic to Iran. Originally proposed as a subgenus of Nannolene Bollman, 1887 (Mauriès, 1983).

Order Julida Brandt, 1833 – (2[5] superfamilies, 2[16] families).

Superfamily Blaniuloidea C. L. Koch, 1847 – (1[4] families).

Family Blaniulidae C. L. Koch, 1847 – (1[22] genera, 1[67] species).

Genus Nopoiulus Menge, 1851 – (3[11] species).

Superfamily Juloidea Leach, 1814 – (1[4] families).

Family Julidae Leach, 1814 – (10[ca 75] genera, 31[700+] species).

Genus Brachyiulus Berlese, 1884 – (1[ca 7] species).

Genus Calyptophyllum Brolemann, 1922 – (4[10] species).

Genus Catamicrophyllum Verhoeff, 1900 – (1[12] species).

Genus Cylindroiulus Verhoeff, 1894 – (5[ca 130] species)

Genus Iraniulus Attems, 1951 – (1[2] species).

Genus Leptoiulus Verhoeff, 1894 – (6[ca 77] species).

Genus Ommatoiulus Latzel, 1884 – (1[80+] species).

Genus Omobrachyiulus Lohmander, 1936 – (1[ca 25] species).

Genus Syriobrachyiulus Verhoeff, 1930 – (2[3] species).

Genus Syrioiulus Verhoeff, 1914 – (9[ca 15] species).

Superorder Merochaeta Cook, 1895 – (1[1] order, 2[27] families).

Order Polydesmida Leach, 1815 – (2[5] suborders, 2[27] families).

Suborder Strongylosomatidea Brölemann, 1916 – (1[1] family).

Family Paradoxosomatidae Daday, 1889 – (4[200+] genera, 9[1,000+] species).

Remarks. The largest family of Diplopoda mostly occurred in tropical or subtropical.

Genus Lohmanderodesmus Schubart, 1934 – (1[2] species).

Genus Oxidus Cook, 1911 – (1[5] species).

Genus Strongylosoma Brandt, 1833 – (3[12] species).

Genus Tetrarthrosoma Verhoeff, 1898 – (4[12] species[subspecies).

Suborder Polydesmidea Pocock, 1887 – (1[4] superfamilies, 1[10] families).

Superfamily Polydesmoidea Leach, 1815 – (1[3] families).

Family Polydesmidae Leach, 1815 – (1[ca 30] genera, 2[270+] species)

Genus Brachydesmus Heller, 1858 – (2[ca 75] species).

DISCUSSION

Formally, the diplopod fauna of Iran presently contains 54 species from 27 genera, 13 families and eight orders (Table 1). The dominant group is by far the order Julida (29 species, 11 genera and two families), followed by 10 species, five genera and two families of Polydesmida. The remaining orders, families, genera and species are clearly subordinate in terms of diversity. The fauna can generally be described as rather poor, expectedly richer only due to the relatively numerous endemic or subendemic Hyrcanian species (33), especially in the julidan genera Nopoiulus, Calyptophyllum, Leptoiulus and Syrioiulus. The absence of higher diplopod taxa endemic or subendemic to Hyrcania is noteworthy, markedly contrasting the Colchidan fauna which, within Russia, Abkhazia and Georgia alone, is much richer and more diverse. Currently, it amounts to 130+ species, 40+ genera, 12 families and seven orders (e.g. Antić & Makarov, 2016; Golovatch et al., 2016; Evsyukov, 2016; Evsyukov et al., 2016, 2018, 2020, 2021; Short et al., 2020; Kokhia & Golovatch, 2020), including numerous species and several genera endemic to Colchis. That Iran, a very vast, but mostly quite arid territory, supports only a moderately rich millipede fauna is hardly surprising. The same concerns the predominance of Palaearctic elements.

 Yet there is a remarkable exception represented by both known species of the genus Chiraziulus, definitely, an ancient relict and the only indigenous member of the suborder Cambalida, order Spirostreptida in the entire Near East. The present distribution pattern of this suborder is Nearctic (together with the Hawaiian Islands, Pacific Ocean) in the New World, but rather Oriental, both tropical and subtropical, in Indo-Australasia (together with the Mascarene Islands, Indian Ocean). Remarkably, the only fossil record of a cambalidean concerns the Oligocene of France (Shelley & Golovatch, 2011). Moreover, one of the species of Chiraziulus is the only troglobiont millipede to be reported from Iran.

Table 1. Fauna and chorology of the Diplopoda of Iran and Hyrcania.

Chorotypes, from wider to increasingly narrower distributions: A — Anthropochoric introduction; EuMe — Euro-Mediterranean; eM — eastern Mediterranean (including the Near East); Ca — Caucasian to pan-Caucasian; ISe — subendemic to Iran beyond Hyrcania; IE — endemic to Iran beyond Hyrcania; H — pan-Hyrcanian; He — endemic to Iranian Hyrcania; T — troglobiont (Golovatch et al., 2022). Asterisk — an uncertain status (Enghoff & Moravvej, 2005).

Endemism in the Diplopoda fauna of Iran is expectedly overwhelming, amounting to ca 80% at the species level, but nearly absent at any higher rank. As noted earlier, Chiraziulus is the sole exception. Naturally, the above estimates are only provisional as the fauna is still far from fully assessed. Thus, seven species are still of uncertain status: Cylindroiiilus cf. besucheti, ?Syrioiulus zarudnyi, Lohmanderodesmus setiger, Strongylosoma uniseriale, Tetrarthrosoma maceratum, T. persicum and T. syriacum. These five latter paradoxosomatids may well be synonyms of other Iranian species (Enghoff & Moravvej, 2005). Syrioiulus taliscius, a species originally described from the Talysh Mountains within the Republic of Azerbaijan (Attems, 1927), has been erroneously quoted for the Iranian part of Hyrcania as well (Golovatch et al., 2022). However, Syrioiulus armeniacus, S. taliscius and Leptoiulus meskhii, like a few other millipedes so far conventionally referred to as endemic to the Hyrcanian part of the Republic of Azerbaijan alone, have been recorded so close to the borders of NW Iran that they could be listed herewith as potentially occurring in Iran as well.

The remaining species include three widespread anthropochores: Brachyiulus lusitanus, Cylindroiulus truncomm and Oxidus gracilis, all definitely introductions. These may well be joined by Nopoilus kochii (Gervais, 1847), a subcosmopolitan species very common and widespread in the Caucasus, but not yet formally recorded from Iran (Golovatch & Enghoff, 1990). Quite expectedly, the closest ties of the Iranian diplopod fauna lie with the Republic of Azerbaijan, to a much lesser extent with Armenia or Iraq, this in particular being due to the numerous Hyrcanian elements shared. Together with several other species, as well as genera, families and orders, the millipede list of Iran can generally be considered as Caucasian, part of the eastern Mediterranean realm. Further taxonomic research in the Diplopoda of Iran will undoubtedly enrich and refine the faunal list presented herewith.

AUTHOR′S CONTRIBUTION

The author confirms that the entire work has been written by himself alone.

FUNDING

No special funding except my salary at the Russian Academy of Sciences.

AVAILABILITY OF DATA AND MATERIAL

The main sources for the published material are Enghoff & Moravvej (2005), Enghoff et al. (2015) and Golovatch et al. (2022).

ETHICS APPROVAL AND CONSENT TO PARTICIPATE

This study only included a list of the arthropod material, and all required ethical guidelines for the treatment and use of animals were strictly adhered to in accordance with international, national, and institutional regulations. No human participants were involved in any studies conducted by the author for this article.

CONSENT FOR PUBLICATION

Not applicable.

CONFLICT OF INTERESTS

The author declares that there is no conflict of interest regarding the publication of this paper.

ACKNOWLEDGMENTS

I am grateful to the Russian Academy of Sciences, Moscow for the support they render to my research.