Research Article |
Corresponding author: Julia Shrubovych ( shrubovych@gmail.com ) Academic editor: Louis Deharveng
© 2018 Julia Shrubovych, Ernest C. Bernard.
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:
Shrubovych J, Bernard EC (2018) A key for the determination of European species of Eosentomon Berlese, 1909 (Protura, Eosentomata, Eosentomidae). ZooKeys 742: 1-12. https://doi.org/10.3897/zookeys.742.22664
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European species of Eosentomon are examined. A taxonomic key to identification of 61 Eosentomon species is provided based on body chaetotaxy, shape, and position of sensilla on the foretarsus and shape of sensilla on the maxillary palps. Biogeographically, 13 of the known European Eosentomon species are known only from their type localities.
Europe, Eosentomon , Protura , taxonomic key
The proturan genus Eosentomon Berlese, 1909 has a worldwide distribution and contains approximately 310 described species (
Type materials were examined of 31 Eosentomon species deposited in the collection of Prof. Szeptycki in the Institute of Systematics and Evolution of Animals PAS, eight Eosentomon species in the collection of J. Rusek in the Institute of Soil Biology BCCAS and one species deposited in the collection the State Museum of Natural History NASU. Information about the taxonomy of other Eosentomon species was taken from original descriptions or redescriptions of type materials in
The geographical distribution of these species is given according to recent published data (
Taxonomic characters used in the key are present in juvenile stages as well as the adults. The shapes of the parts of the adult female squama genitalis may have great phylogenetic value and can serve as additional characters for identification of species. The characters used in the key, such as shape of maxillary palpi, chaetotaxy of the head, shape and position of sensilla on the foretarsus and position of seta P1a on tergite VII are stable from the second juvenile stage (larva I) (
Analysis of the geographical distribution of European Eosentomon shows that nearly all species have been collected only in Europe, except for two (E. delicatum and E. mixtum) that have also been recorded from northern Africa. The majority of the species have been recorded only from Central Europe, probably due to many years of active work in this region by Josef Nosek, Josef Rusek and Andrzej Szeptycki. Sixteen species are known from Western Europe and only two species have been reported from Eastern Europe (Table
Distribution pattern of Eosentomon species in European biogeographical regions.
Species | Countries | Biogeographical regions |
---|---|---|
E. armatum Stach, 1927 | Nearly all of Europe | Continental-Pannonian-Mediterranean |
E. bloszyki Szeptycki, 1985 | Poland, Czech Republic, Luxembourg, Germany, Austria, Ukraine | Continental |
E. boedvarssoni Nosek, 1973 | Sweden | Boreal |
E. bohemicum Rusek, 1966 | Czech Republic, Poland | Continental |
E. briophillum Szeptycki, 1986 | Poland, type locality only | Continental |
E. canarinum Szeptycki, 2004 | Canary Islands | Macaronesian |
E. carolae Condé, 1947 | France, Spain | Mediterranean |
E. carpaticum Szeptycki, 1985 | Poland, Ukraine, Romania, Hungary, Slovakia | Alpine-Continental |
E. cetium Szeptycki & Christian, 2000 | Austria, type locality only | Continental |
E. coiffaiti Condé, 1961 | Minorca, Serbia | Macaronesian-Continental |
E. condei da Cunha, 1950 | Portugal, Spain | Mediterranean |
E. delicatum Gisin, 1945 | All Europe, North Africa | Alpine-Boreal-Continental-Pannonian-Mediterranean |
E. denisi Condé, 1947 | France, Spain | Mediterranean |
E. enigmaticum Szeptycki, 1986 | Poland, Ukraine, Romania, Slovakia | Alpine-Continental |
E. fichteliense Rusek, 1988 | Germany, type locality only | Continental |
E. foliaceus Rusek, 1988 | Germany, Poland | Continental |
E. foroiuliense Torti & Nosek, 1984 | Italy, type locality only | Continental |
E. funkei Rusek, 1988 | Germany, Luxembourg | Continental |
E. gamae Aldaba, 1986 | Portugal, type locality only | Mediterranean |
E. germanicum Prell, 1912 | Nearly all of Europe, Morocco | Alpine-Boreal-Continental-Mediterranean |
E. gisini Nosek, 1967 | Austria, Slovakia | Alpine |
E. gramineum Szeptycki, 1986 | Poland, Ukraine | Continental |
E. kamenickiense Rusek, 1974 | Czech Republic, type locality only | Continental |
E. longisquamum Szeptycki, 1986 | Poland, Austria | Continental |
E. lusitanicum Aldaba, 1986 | Portugal, type locality only | Mediterranean |
E. luxembourgense Szeptycki, 2001 | Luxembourg, Austria | Continental |
E. mariae Szeptycki, 1986 | Poland, Austria, Germany, Luxembourg, Ukraine | Continental |
E. mirabile Szeptycki, 1984 | Poland, Germany, Austria, Canary Islands, France, Ukraine | Continental-Macaronesian |
E. mixtum Condé, 1945 | France, Austria, Czech Republic, Germany, Slovakia, Madeira | Alpine-Continental-Macaronesian |
E. noseki Tuxen, 1982 | Macaronesia, Spain, Italy | Macaronesian-Mediterranean |
E. occidentale Szeptycki, 1985 | Poland | Continental |
E. palustre Szeptycki & Sławska, 2000 | Poland, type locality only | Continental |
E. parvum Szeptycki, 1986 | Austria, Poland | Continental |
E. pastorale Szeptycki, 2001 | Austria, Luxembourg | Continental |
E. paucrum Szeptycki, 2001 | Luxembourg | Continental |
E. pinetorum Szeptycki, 1984 | Austria, Czech Republic, Poland, Ukraine, Romania | Alpine-Continental |
E. pinkyae Arbea-Polite, 1990 | Spain, type locality only | Mediterranean |
E. polonicum Szeptycki, 1985 | Poland | Continental |
E. posnaniense Szeptycki, 1986 | Poland, Austria | Continental |
E. pratense Rusek, 1973 | Czech Republic, Poland, former Yugoslavia, Slovakia, Germany, Austria, Ukraine | Continental |
E. rafalskii Szeptycki, 1985 | Poland, Czech Republic, Germany | Continental |
E. romanum Nosek, 1969 | Italy | Mediterranean-Continental |
E. rusekianum Stumpp & Szeptycki, 1989 | Germany, Austria, Poland | Continental |
E. scytha Shrubovych & Szeptycki, 2008 | Ukraine, type locality only | Continental |
E. semiarmatum Szeptycki, 1986 | Balearic Islands, France, Germany, Poland, Ukraine, Romania | Mediterranean-Continental |
E. sexsetosum Szeptycki, 1985 | Luxembourg, Poland | Continental |
E. silesiacum Szeptycki, 1985 | Germany, Czech Republic, Poland, Luxembourg, Sweden | Boreal-Continental |
E. silvaticum Szeptycki, 1986 | Poland, Luxembourg, Romania | Alpine-Continental |
E. solarzi Szeptycki, 1993 | European part of Russia, type locality only | Continental |
E. stachi Rusek, 1966 | Austria, Luxembourg, Poland, Slovakia, Ukraine, Romania | Alpine - Continental |
E. stompi Szeptycki & Weiner, 1993 | Germany, Luxembourg | Continental |
E. stumppi Rusek, 1988 | Germany, Austria | Continental |
E. sudeticum Szeptycki, 1985 | Poland, Czech Republic | Continental |
E. transitorium Berlese, 1909 | all Europe | Alpine-Boreal-Continental-Pannonian-Mediterranean |
E. ulinense Szeptycki, 1999 | Poland | Continental |
E. umbrosum Szeptycki, 2001 | Luxembourg | Continental |
E. vindobonense Szeptycki & Christian, 2000 | Austria, type locality only | Continental |
E. vulgare Szeptycki, 1984 | Poland, Czech Republic, Germany, Austria, Luxembourg, Ukraine | Continental |
E. wanda Szeptycki, 1985 | Poland, type locality only | Continental |
E. weinerae Szeptycki, 2001 | Austria, Luxembourg | Continental |
E. zodion Szeptycki, 1985 | Poland, Ukraine | Continental |
The existence of at least 61 European Eosentomon species, with only two of its species outside the continent (Mediterranean Africa), strongly suggests that the remaining continents must have many more species than are currently known from them. All of the world’s Eosentomon species have ranges restricted to a single continent, and most are apparently specialized to a particular biome or specialized habitat. Much more collecting needs to be done, even in Europe, for us to understand the diversity of these enigmatic hexapods.
1 | Tergite VII with 2 A-setae (seta A4) | 2 |
– | Tergite VII with greater number of A-setae | 3 |
2 | Tergite IV with 8 A-setae (A5 absent), foretarsal sensillum a clearly shorter than c (see |
E. kamenickiense |
– | Tergite IV with 10 A-setae (A5 present), foretarsal sensilla a and c equal in length (see |
E. pratense |
3 | Tergite VII with 4 A-setae (setae A4, A5) | 4 |
– | Tergite VII with other number of A-setae | 28 |
4 | Tergite V with 8 A-setae (A3 absent) | 5* |
– | Tergite V with 10 A-setae (A3 present) | 16 |
5 | Head with aa and pa setal pairs | 6 |
– | Head with one pair or without additional setae | 11 |
Two species, E. denisi and E. condei, will key to couplet 5 but their cephalic chaetotaxy is unknown. Eosentomon denisi possesses eight A-setae on tergites V–VII, the female squama genitalis is of the “wheeleri” type (see |
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6 | Seta P1a at level of P2 on tergite VII (see |
7 |
– | Seta P1a posterior to level of P2, extending past hind margin of tergite VII | 10 |
7 | Foretarsal sensillum d long, reaching base of t3 ( |
8 |
– | Foretarsal sensillum d short, reaching base of α5 (see |
9 |
8 | Foretarsal sensillum c’ long, base proximal to line α6 – δ5 ( |
E. bloszyki |
– | Foretarsal sensillum c’ short, base distal to line α6 – δ5 ( |
E. paucrum |
9 | Foretarsal sensillum t1 nearer to α3’ than to α3, rostral and subrostral setae equal in length (see |
E. pastorale |
– | Sensillum t1 midway between α3 and α3’, rostral setae shorter than subrostral setae (see |
E. palustre |
10 | Foretarsal sensillum c’ thick, proximal to line α6 – δ5 (see |
E. stachi |
– | Foretarsal sensillum c’ slender, on line α6 – δ5 (see |
E. carpaticum |
11 | Head with pa setae only, foretarsal sensillum b’2 very long, foliaceous (see |
E. foliaceus |
– | Head without additional setae, foretarsal sensillum b’2 shorter, sensilliform | 12 |
12 | Notal seta P2a clearly longer than one-third the length of P3a; setae on tergite XI very short, one-sixth the length of those on tergite X (see |
13 |
– | Notal setae P2a one-third the length of P3a; setae on tergite XI half as long as setae on tergite X (see |
15 |
13 | Tergite VI with 8 A-setae (A3 absent) (see |
14 |
– | Tergite VI with 6 A-setae (A1, A3 absent) (see |
E. sexsetosum |
14 | Dorsal sensillum on maxillary palpus longer than lateral sensillum, rostral and subrostral setae subequal (see |
E. occidentale |
– | Sensilla on maxillary palpus equal in length, rostral and subrostral setae subequal (see |
E. stompi |
15 | Tergite IV with 8 A-setae (A3 absent), dorsal sensillum on maxillary palpus longer than lateral sensillum (see |
E. bohemicum |
– | Tergite IV with 10 A-setae, sensilla on maxillary palpus equal in length (see |
E. polonicum |
16 | Tergite VI with 10 A-setae | 17 |
– | Tergite VI with 8 A-setae | 18 |
17 | Foretarsal sensilla a and c short, sensillum f2 very short, one-fifth length of f1 (see Torti and Nosek 1984: fig. 1B), length of foretarsus 112 μm | E. foroiuliense |
– | Foretarsal sensillum a longer than c, sensilla f1 and f2 nearly equal in length, female squama genitalis with small beak-like terminus (see |
E. pinkyae |
18 | Seta P1a at level of P2 on tergite VII (see |
19 |
– | Seta P1a posterior to level of P2 on tergite VII | 21 |
19 | Foretarsal sensilla a and c equal in length, female squama genitalis of “romanum” type (see |
E. romanum |
– | Foretarsal sensillum a clearly shorter than c, female squama genitalis of “transitorium” type (see |
20 |
20 | Foretarsal sensillum c’ proximal to base of α6 or to line α6 – δ5, broad (see |
E. luxembourgense |
– | Foretarsal sensillum c’ to line α6 – δ5, slender (see |
E. delicatum |
21 | Foretarsal sensillum c’ on line α6 – δ5 | 22 |
– | Foretarsal sensillum c’ proximal to line α6 – δ5 | 24 |
22 | Foretarsal sensillum t1 nearer to α3’ than to α3, sensilla on maxillary palpus nearly equal in length (see |
E. wanda |
– | Foretarsal sensillum t1 midway between α3 and α3’ or nearer to α3, dorsal sensillum on maxillary palpus clearly longer than lateral (see |
23 |
23 | Sensillum t1 midway between α3 and α3’, rostral and subrostral setae equal in length ( |
E. scytha |
– | Sensillum t1 much closer to α3 than to α3’, rostral setae slightly shorter than subrostral setae (see |
E. zodion |
24 | Head with aa and pa setae | 25 |
– | Head with pa setae only (see |
27 |
25 | Sensilla on maxillary palpus thick, foretarsal sensillum a half the length of c (see |
26 |
– | Sensilla on maxillary palps slender, foretarsal sensilla a and c nearly equal in length (see |
E. armatum |
26 | Dorsal sensillum on maxillary palpus clearly longer than lateral sensillum (see |
E. noseki |
– | Sensilla on maxillary palpus nearly equal in length (see |
E. canarinum |
27 | Foretarsal sensillum c’ in half distance between α6 – δ4’, seta P2a on nota equal in length to P3a (see Szeptycki: figs 32, 37), length of foretarsus 65 μm | E. umbrosum |
– | Foretarsal sensillum c’ closer to δ4’ than to α6, seta P2a shorter than P3a (see |
E. stumppi |
28 | Tergite VII with 10 A-setae (see |
E. boedvarssoni |
– | Tergite VII with fewer A-setae | 29 |
29 | Tergite VII with 8 A-setae (A3 absent) (see |
30 |
– | Tergite VII with 6 A-setae (A1, A3 absent) | 31 |
30 | Sternites IX – X with 6 setae, female squama genitalis of “wheeleri” type ( |
E. carolae |
– | Sternites IX – X with 4 setae, female squama genitalis of “transitorium” type (see |
E. gamae |
31 | Tergite VI with 10 A-setae | 32 |
– | Tergite VI with 8 A-setae | 57 |
32 | Sternites IX – X with 4 setae | 33 |
– | Sternites IX – X with 6 setae (sternite X with 4 setae in maturus junior) | 48 |
33 | Head with aa and pa setae (J. Rusek, pers. comm.; |
34 |
– | Head with pa setae or without additional setae | 35 |
34 | Foretarsal sensillum t1 midway between α3 and α3’, rostral seta evidently shorter than subrostral (see |
E. gisini |
– | Foretarsal sensillum t1 near to α3’, rostral and subrostral setae equal in length (see |
E. pinkyae |
35 | Head without additional setae | 36 |
– | Head with pa setae | 37 |
36 | Basal seta D2 on hind leg about half the length of D1 (see |
E. rafalskii |
– | Basal seta D2 on hind leg subequal with D1 (see |
E. silesiacum |
37 | Basal seta D2 on hind leg spine-like | 38 |
– | Basal seta D2 on hind legs setiform | 46 |
38 | Seta P1a not reaching hind margin of tergite VII | 39 |
– | Seta P1a extending past hind margin of tergite VII | 42 |
39 | Sensilla on maxillary palps short and equal in length (see |
40 |
– | Maxillary sensilla long, lateral sensillum longer than dorsal | 41 |
40 | Notal setae P1 longer than P1a, foretarsal sensillum f1 spatuliform (see |
E. bryophilum |
– | Notal setae P1 shorter than P1a, foretarsal sensillum f1 filiform (see |
E. vindobonense |
41 | Length ratio of notal setae P1:P1a ≥1.5 (see |
E. enigmaticum |
– | Length ratio of notal setae P1:P1a ≤1.3 (see |
E. gramineum |
42 | Sensilla on maxillary palpus nearly equal in length (see |
43 |
– | Lateral sensillum of maxillary palpus much longer than dorsal sensillum (see |
44 |
43 | Notal setae P1a and P1 nearly equal in length (see |
E. longisquamum |
– | Notal seta P1a shorter than P1 ( |
E. cetium |
44 | Seta P1a on tergites I – VI longer than P1, foretarsal sensillum t1 nearer to α3 than to α3’, sensillum t3 longer than c’, length of foretarsus less than 100 μm | 45 |
– | Seta P1a on tergites I – VI equal in length or shorter than P1, foretarsal sensillum t1 midway between α3 and α3’ or slightly closer to a3’, sensillum t3 short, equal in length to c’, length of foretarsus 100–110 μm (see |
E. silvaticum |
45 | Tracheal camerae long, slender; foretarsal sensillum d long, reaching base of α6, length of foretarsus 90–100 μm (see |
E. semiarmatum |
– | Tracheal camerae short, stocky; foretarsal sensillum d short, not reaching base of α5, length of foretarsus 75–85 μm (see |
E. parvum |
46 | Seta P1a at level P2 on tergite VII | 47 |
– | Seta P1a slightly posterior to P2 and extending past hind margin of tergite VII (see |
E. posnaniense |
47 | Rostral seta thinner than subrostral seta (see |
E. transitorium |
– | Rostral seta thicker than subrostral seta, sensilla on maxillary palpus nearly equal, foretarsal sensillum t1 nearer α3’ than α3 (see |
E. mariae |
48 | Seta P1a at level of P2 on tergite VII | 49 |
– | Seta P1a posterior to level of P2 on tergite VII | 52 |
49 | Foretarsal sensillum f1 thickened apically, body length more than 1600 μm (see |
E. mixtum |
– | Foretarsal sensillum f1 not thickened apically, body length less than 1600 μm | 50 |
50 | Foretarsal sensillum f1 thick, thicker than sensillum a (see |
E. lusitanicum |
– | Foretarsal sensillum f1 thin (see |
51 |
51 | Foretarsal sensillum t1 midway between α3 and α3’, sensillum f2 sensilliform (see |
E. funkei |
– | Foretarsal sensillum t1 nearer α3 than α3’, sensillum f2 spatuliform (see |
E. coiffaiti |
52 | Head with both aa and pa setae | 53 |
– | Head with aa or pa setae | 54 |
53 | Foretarsal sensillum a longer than half the length of c, sensillum f1 spatulate (see |
E. mirabile |
– | Foretarsal sensillum a shorter than half the length of c, sensillum f1 filiform (see |
E. weinerae |
54 | Head with aa setae (see |
E. rusekianum |
– | Head with pa setae only | 55 |
55 | Lateral sensillum on maxillary palpus clearly longer than dorsal, spatulate dilation on foretarsal sensilla e and g short, about third of sensillum length, tracheal camerae long (see |
E. vulgare |
– | Sensilla on maxillary palps nearly equal in length, spatulate dilation on foretarsal sensilla e and g long, about half of sensillum length, tracheal camerae short and thickened (see |
56 |
56 | Foretarsal sensillum a about half of c length, lateral sensillum on maxillary palpus slightly shorter than dorsal (see |
E. pinetorum |
– | Foretarsal sensillum a about equal in length to c, sensilla on maxillary palpus equal in length (see |
E. fichteliense |
57 | Sternites IX – X with 4 setae | 58 |
– | Sternites IX – X with 6 setae, head with pa setae (see |
E. germanicum |
58 | Head without additional setae ( |
E. sudeticum |
– | Head with pa setae, length of foretarsus ≤85µm | 59 |
59 | Head with both aa and pa setae (see |
E. ulinense |
– | Head with only pa setae (see |
E. solarzi |
The authors are grateful to Prof. Josef Rusek for his valuable comments on taxonomy and to Jakub Sternalski for his help with preparation this manuscript. We also thank the peer reviewers, Loris Galli and Yun Bu, and subject editor Louis Deharveng for their valuable remarks and corrections of the text.