On the Taxonomy of the Acanthocyclops robustus Species-Complex (Copepoda, Cyclopidae): Acanthocyclops brevispinosus and A. einslei sp. n
Приведены новые сведения по морфологии Acanthocyclops brevispinosus (Herrick, 1884). Вид, ранее ошибочно идентифицировавшийся как A. robustus (sensu Petkovski, 1975; Kiefer, 1976; Einsle, 1997 и др.), описан в качестве нового вида A. einslei Mirabdullayev & Defaye, sp. n. Приведены данные по рас...
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Інститут зоології ім. І. І. Шмальгаузена НАН України
2004
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| Zitieren: | On the Taxonomy of the Acanthocyclops robustus Species-Complex (Copepoda, Cyclopidae): Acanthocyclops brevispinosus and A. einslei sp. n / I. M. Mirabdullayev, D. Defaye // Вестн. зоологии. — 2004. — Т. 38, № 5. — С. 27-37. — англ. |
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| citation_txt | On the Taxonomy of the Acanthocyclops robustus Species-Complex (Copepoda, Cyclopidae): Acanthocyclops brevispinosus and A. einslei sp. n / I. M. Mirabdullayev, D. Defaye // Вестн. зоологии. — 2004. — Т. 38, № 5. — С. 27-37. — англ. |
| collection | DSpace DC |
| description | Приведены новые сведения по морфологии Acanthocyclops brevispinosus (Herrick, 1884). Вид, ранее ошибочно идентифицировавшийся как A. robustus (sensu Petkovski, 1975; Kiefer, 1976; Einsle, 1997 и др.), описан в качестве нового вида A. einslei Mirabdullayev & Defaye, sp. n. Приведены данные по распространению и изменчивости.
New data on morphology of Acanthocyclops brevispinosus (Herrick, 1884) are provided. A. einslei Mirabdullayev & Defaye, sp. n., previously misidentified as (sensu Petkovski, 1975; Kiefer, 1976; Einsle, 1997 et al.) is described.
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UDC 595.34
ON THE TAXONOMY OF THE ACANTHOCYCLOPS ROBUSTUS
SPECIES–COMPLEX (COPEPODA, CYCLOPIDAE):
ACANTHOCYCLOPS BREVISPINOSUS AND A. EINSLEI SP. N.
I. M. Mirabdullayev 1, D. Defaye 2
1 Institute of Zoology, Niyazov str., 1, Tashkent, 700095 Uzbekistan
E-mail: iskandar@mail.tps.uz
2 Museum national d’Histoire naturelle, rue de Buffon, 61, Paris, F75005 France
E-mail: ddefaye@mnhn.fr
Accepted 11 February 2004
On the Taxonomy of the Acanthocyclops robustus Species-Complex (Copepoda, Cyclopidae): Acanthocyc-
lops brevispinosus and A. einslei sp. n. Mirabdullayev I. M., Defaye D. — New data on morphology of
Acanthocyclops brevispinosus (Herrick, 1884) are provided. A. einslei Mirabdullayev & Defaye, sp. n.,
previously misidentified as (sensu Petkovski, 1975; Kiefer, 1976; Einsle, 1997 et al.) is described.
Ke y wo r d s: Crustacea, Cyclopidae, new species.
Òàêñîíîìèÿ êîìïëåêñà âèäîâ Acanthocyclops robustus (Copepoda, Cyclopidae): Acanthocyclops brevi-
spinosus è A. einslei sp. n. Ìèðàáäóëëàåâ È. Ì., Äåôàé Ä. — Ïðèâåäåíû íîâûå ñâåäåíèÿ ïî ìîð-
ôîëîãèè Acanthocyclops brevispinosus (Herrick, 1884). Âèä, ðàíåå îøèáî÷íî èäåíòèôèöèðîâàâ-
øèéñÿ êàê A. robustus (sensu Petkovski, 1975; Kiefer, 1976; Einsle, 1997 è äð.), îïèñàí â êà÷åñòâå
íîâîãî âèäà A. einslei Mirabdullayev & Defaye, sp. n. Ïðèâåäåíû äàííûå ïî ðàñïðîñòðàíåíèþ è
èçìåí÷èâîñòè.
Êëþ÷åâûå ñ ëîâ à: Crustacea, Cyclopidae, íîâûé âèä.
Introduction
The freshwater cyclopid genus Acanthocyclops (Kiefer, 1927) has a world-wide distribution and
comprises about fifty species and subspecies. It is important in ecological respect since most of the species
inhabit continental waterbodies, as well as being components of the plankton as well as of the benthon and
in some cases subterranean biotopes. The genus has been the subject of numerous papers, especially concer-
ning two widespread species, Acanthocyclops vernalis (Fischer, 1853) and Acanthocyclops robustus (G. O. Sars,
1863). Their identification long remained problematic and has been largely discussed during the last decades
because of ecological variability of the morphological characters used for their identification.
The importance of the variability of these two «phenotypically plastic» species, in terms of size, furcal
index, relative length of furcal setae, ornamentation of setae and spines of the natatory legs, and even spine
formula has been recorded by different authors, both in field and laboratory studies (Kiefer, 1976; Dodson,
1994; Einsle, 1993; Lescher-Moutoue ´, 1996). V. Einsle (1992, 1996) pointed out the need to take into
account all these morphological characters with critical attention, as well as the usefulness of other characters,
such as the number of chromosomes.
After re-examining a number of specimens identified as A. robustus, we came to the conclusion that it
was also necessary to re-examine specimens of the taxa considered as its synonyms: A. robustus f. limnetica
Petkovski, 1975 and A. americanus (Marsh, 1873) (Kiefer 1978; Dussart, Defaye, 1985). A. brevispinosus
(Herrick, 1894) has been recognised by Dodson (1994) as a valid species and carefully redescribed by Dahms,
Fernando (1997) and should no longer be considered as a synonym of A. robustus or A. vernalis. Although it
has a laterally rounded genital segment, it differs from A. robustus by several characters, particularly the
setation pattern of the proctodeum and the spatulate spines on P3 and P4. A. americanus have been generally
identified considering specimens of robustus-like Acanthocyclops showing a rounded genital segment and
characteristics of the furca and the endopodite of P4 (Lowndes, 1926; Gurney, 1933; Ðûëîâ, 1948; Dussart,
1969; Monchenko, 1974; Alekseev, Kosova, 1976; Alekseev, 1995 etc.).
F. Kiefer (1976), in comparing specimens of A. robustus from G. O. Sars’s collection with those
identified by C. D. Marsh as A. americanus concluded that these forms were conspecific. He established then
Vestnik zoologii, 38(5): 27–37, 2004
© I. M. Mirabdullayev, D. Defaye, 2004
also that, in fact, there were two different species (both determined as A. americanus) in Marsh’ s collection,
one with rounded genital segment (robustus-like) and other with laterally angled genital segment (vernalis-
like). Kiefer’s synonymy of A. americanus Marsh with A. robustus Sars has been accepted by most copepo-
dologists (Petkovski, 1975; Fryer, 1985; Defaye, Dussart, 1985; Kawabata, Defaye, 1994; Dodson, 1994;
Einsle, 1996; Dahms, Fernando, 1997).
Studying Acanthocyclops robustus from waterbodies of Yugoslavia, T. Petkovski (1975) described a new
form — A. robustus f. limnetica. He thought that this form differed only slightly from the typical form, mostly
by characters of Enp3P4: the ratio between the length of inner apical spine of Enp3P4 and the width of
Enp3P4 which is over 2.00 (2.10–2.40), compared with only 1.40–1.60 for the typical form. Enp3P4 of the
limnetic form is also thinner, with L: W over 2.30 (2.31–2.40), whereas in the typical form, it is significantly
lower (1.95–2.30) (Petkovski, 1975).
In studying specimens identified as A. robustus from waterbodies of Europe, Asia, America and North
Africa, we also could distinguish two forms, corresponding to Petkovski’s forms. Detailed study has revealed
additional characters which allow the unambiguous separation of these forms and support their separation as
valid species. The comparison of these species with specimens from G. O. Sars’s collection have unexpectedly
revealed differences, which require a revision of the whole group.
In previous paper (Mirabdullayev, Defaye, 2002) we redescribed Acanthocyclops robustus (Sars, 1863).
In this article we describe Acanthocyclops einslei sp. n. Additional data are provided concerning morphology
and variability of A. brevispinosus (Herrick, 1894).
Abbreviations: Me — lateral furcal seta; Ti — innermost apical furcal seta; Tmi — inner medial apical
furcal seta; Tme — outer medial apical furcal seta; Te — outermost apical furcal seta; Sd — dorsal furcal seta.
Acanthocyclops brevispinosus (Herrick, 1884) (fig. 1–2)
Cyclops brevispinosus Herrick, 1884. Acanthocyclops brevispinosus (Herrick, 1884): Einsle, 1992, part.,
Figs. 9Z, 12; Dodson, 1994; Dahms, Fernando, 1997.
Ma t e r i a l e x am in ed. USA: 3 }, Lake Erie, N. Y., 12.07.1928, USNM 62594, C. Marsh Collection;
}, Wisconsin, Mirror Lake, 10.06.1989, USNM 259375, S. Dodson Coll.; Detroit River, 20.04.1988, U. Ein-
sle Coll. 3785–3787; }, Indiana, Lake Maxinkuckee, Kiefer Coll. 10518. Canada: 2 }, Lake Pinehurst,
Ontario, 22.06.1992 (leg. H.-U. Dahms); 3 }, Columbia Reservoir, Ontario, 18.05.1992 (leg. H.-U. Dahms).
Acanthocyclops brevispinosus has been redescribed in detail by Dahms and Fernan-
do (1997). However, the ornamentation of caudal side of the basipodite of antenna was
not figured by these authors (fig. 1–2).
Some additional characters can be noted: aesthetasc on 12th segment of antennule
not reaching distal margin of 14th segment; inner distal claw-like seta of basipodite of
maxilla smooth; length ratio of the two shortest apical setae of Enp2 of maxil-
liped = 1.55–1.80; intercoxal plates of P1–P3 without ornamentation; Enp3P4 2.2–2.5
times as long as wide, inner apical spine 0.75–0.95 times as long as segment and usu-
ally slightly shorter than outer spine, outer lateral spine (very rarely a seta) situated at
0.70–0.80 of the segment length; spine formula of the exopodites of P1 to P4: 3.4. 4.4
(no variability observed). Furcal setae: Ti very short, 0.4–0.5 times as long as furca.
Ti/Tmi = 0.12–0.16; Ti/Tme = 0.19–0.21; Ti/Te = 0.95–1.30; Ti/Sd = 0.80–1.05.
D i f f e r e n t i a l d i a g no s i s. Acanthocyclops brevispinosus differs from A. robustus
and A. petkovskii Pesce et Lattinger mainly by the pattern of setation of the proctodeum
which is a patchy symmetrical field of spinules, by the ornamentation of the antennary
28 I. M. Mirabdullayev, D. Defaye
Fig. 1–2. Acanthocyclops brevispinosus, } (Canada, Ontario, Lake Pinehurst): 1 — basipodite of antenna,
caudal side; 2 — basipodite of antenna, frontal side. Scale bar 50 mkm.
Ðèñ. 1–2. Acanthocyclops brevispinosus, } (Êàíàäà, Îíòàðèî, îç. Ïàéíõóðñò): 1 — áàçîïîäèò àíòåííû,
êàóäàëüíàÿ ñòîðîíà; 2 — áàçîïîäèò àíòåííû, ôðîíòàëüíàÿ ñòîðîíà. Ìàñøòàáíàÿ ëèíåéêà 50 ìêì.
basipodite and by the level of insertion of the outer lateral spine of Enp3P4. It also dif-
fers from both species by the length of the aesthetasc on 12th segment of antennule rel-
ative to the distal margin of 14th segment. It further differs from A. robustus, by the
length ratio of the apicalmost setae of the maxilliped (higher in A. brevispinosus), and
from A. petkovskii by the ornamentation of the claw-like seta of basipodite of maxilla
(absent in A. brevispinosus). Moreover, A. brevispinosus is easily recognisable by the
shape of the lanceolate enlarged spines on P3 and P4, not previously observed in other
taxa of the robustus species-complex.
D i s t r i b u t i o n. Acanthocyclops brevispinosus inhabits waterbodies of Canada and USA.
Eco l o g y. Poorly known. Plankton of lakes and ponds (Dodson, 1994).
Acanthocyclop einslei Mirabdullayev & Defaye, sp. n. (fig. 3–24)
Acanthocyclops robustus (G. O. Sars, 1863), Kiefer (1933); Dussart et al. (1966), part., Figs. 9, 12, 14;
Dussart (1969); Einsle (1996), part., Fig. 53 DR; Petkovski (1975), typical form; Kawabata, Defaye, 1994;
Alekseev et al., 2002. Acanthocyclops robustus f. typica: Mirabdullayev, Dahms, 1999. Acanthocyclops
americanus (Marsh, 1893), Dussart (1970).
Ma t e r i a l e x am in ed. France: 4 }, Lake Creteil, near Paris, Nov. 1969, MNHN–Cp800. Belgium:
}, pond in Ghent, July 1999 (leg. V. Alekseev). Hungary: }, fishpond, 29.05.1992 (leg. M. Holynska).
Germany: many females and males, Oldenburg, Wechloy, ditch near University; July 1998. Italia: }, Trasimeno,
Kiefer’s coll. 7830, }; 10233. Yugoslavia: 10 {, 8 }, Montenegro (leg. T. Karanovic). Uzbekistan: many
specimens from 7 localities in the Tashkent and Samarkand provinces, coll. I. M. Mirabdullayev. Kazakhstan:
4 }, fishpond, Chilik Fishery Farm, Kazakhstan (leg. T. S. Stuge). Japan: {, }, Kahoko, 29.07.1993
29On the Taxonomy of the Acanthocyclops robustus Species-Complex…
Fig. 3–7. Acanthocyclops einslei, holotype, } (Germany): 3 — habitus; 4 — labrum; 5 — antennule; 6 —
antenna, caudal side; 7 — basipodite of antenna, frontal side. Scale bar 50 mkm except 3 : 500 mkm).
Ðèñ. 3–7. Acanthocyclops einslei, holotype, } (Ãåðìàíèÿ): 3 — ãàáèòóñ; 4 — ëàáðóì; 5 — àíòåííóëà; 6 —
àíòåííà, êàóäàëüíàÿ ñòîðîíà; 7 — áàçîïîäèò àíòåííû, ôðîíòàëüíàÿ ñòîðîíà. Ìàñøòàáíàÿ ëèíåéêà
50 ìêì, èñêëþ÷àÿ 3 : 500 ìêì.
(leg. Kawabata). USA: 4 }, Lake Erie, N. Y., 12.07.1928. USNM 62594, Marsh Coll. Canada: many specimens,
Waterloo, Ontario, 22.06.1992 (leg. H.-U. Dahms). Indonesia: }, Sumatra. Kiefer’s coll. 1685–1686.
Ho l o t y p e. A dissected female, from ditch in Wechloy, Oldenburg, Germany, July 1998 mounted on
slide and deposited in the Museum National d’Histoire Naturelle, Paris (France) (MNHN-Cp1873)
P a r a t y p e s: 3 dissected females from the same locality as holotype, mounted on slides, MNHN-
Cp1874 to MNHN–Cp1876; 2 dissected females, from the same locality as the holotype, mounted on slides
and deposited at the Institute of Zoology, Tashkent, Cp111); 2 dissected females, mounted on slide
(Zoologish Museum, Amsterdam); 10 } and 3 {, ethanol preserved and deposited as the holotype (MNHN–
Cp1877); 10 } and 3 {, ethanol preserved, deposited at the Institute of Zoology, Tashkent (De–P1/6).
F ema l e. The description and figures are of the female holotype, except that fig-
ure 6 is of a paratype.
Body length (furcal setae excluded): 1300 mkm.
Antennule short, not reaching the distal margin of the first thoracic somite (fig. 3),
17-segmented, with armature as follows: 8, 4, 2, 6, 4, 1 + spine, 2, 1, 1, 0, 1, 1 + aes-
thetasc, 0, 1, 2, 2 + aesthetasc, 7 + aesthetasc. Aesthetasc on 12th segment of antennule
reaching distal margin of 14th segment. First segment bearing a row of spinules (fig. 5).
Antenna. Ornamentation of basipodite as in figures 6–7, resembling that of A. bre-
vispinosus; spinules of longitudinal row thin and oriented at sharp angle to axis of
basipodite (fig. 6–7). Third segment of antenna bearing 9 setae.
Labrum with 12–13 teeth (fig. 4).
Mandible and maxillule as on figures 8–10.
Maxilla: general shape as in A. robustus. Inner claw-like seta of basipodite smooth
or bearing a few spinules, sometimes a row of spinules present on outer side, but never
with a row of spinules on inner side (fig. 11).
30 I. M. Mirabdullayev, D. Defaye
Fig. 8–12. Acanthocyclops einslei, holotype, } (Germany. MNHN–Cp800): 8 — mandible; 9 — maxillule;
10 — palp of maxillule; 11 — maxilla; 12 — maxilliped. Scale bar 50 mkm.
Ðèñ. 8–12. Acanthocyclops einslei, ãîëîòèï, } (Ãåðìàíèÿ. MNHN–Cp800): 8 — ìàíäèáóëà; 9 — ìàê-
ñèëëóëà; 10 — ùóïèê ìàêñèëëóëû; 11 — ìàêñèëëà; 12 — ìàêñèëëèïåäà. Ìàñøòàáíàÿ ëèíåéêà 50 ìêì.
Maxilliped. General shape as in A. robustus. Length ratio of two apicalmost spines:
1.4 (fig. 12).
Natatory legs (fig. 13–16): spine formula of P1–P4 : 3.4–4.4 (usual formula). Ge-
neral armature as follows:
Coxopodite Basipodite Endopodite Exopoditeiteite
P1 0–1 1–1 0–1; 0–2; 1, I, 4 I-1; I-1; III, [1], 3
P2 0–1 1–0 0–1; 0–2; I, I-1,3 I-1; I-1; III, I–1,3
P3 0–1 1–0 0–1; 0–2; I, II, 3 I-1; I-1; III, I, 4
P4 0–1 1–0 0–1; 0–2; I, II, 2 I-1; I-1; III, I–[1], 3
Intercoxal plates of P1–P3 without ornamentation, intercoxal plate of P4 with row
of spinules on caudal side. Coxopodite of P1–P3 with group of 4–5 long spinules on
caudal side. Coxopodite of P4 with rows of shorter spinules near distal and proximal
31On the Taxonomy of the Acanthocyclops robustus Species-Complex…
Fig. 13–14. Acanthocyclops einslei, holotype, } (Germany. MNHN–Cp800): 13 — P1; 14 — P2. Scale
bar 100 mkm.
Ðèñ. 13–14. Acanthocyclops einslei, ãîëîòèï, } (Ãåðìàíèÿ. MNHN–Cp800): 13 — P1; 14 — P2. Ìàñø-
òàáíàÿ ëèíåéêà 100 ìêì.
Fig. 15–16. Acanthocyclops einslei, holotype, } (Germany. MNHN–Cp800): 15 — P3; 16 — P4. Scale
bar 100 mkm.
Ðèñ. 15–16. Acanthocyclops einslei, holotype, } (Ãåðìàíèÿ. MNHN–Cp800): 15 — P3; 16 — P4.
Ìàñøòàáíàÿ ëèíåéêà 100 ìêì.
margins and 2 rows of longer and thinner spinules near lateral margin. Inner edge of
basipodite P1–P4 with setules. Apical inner edge of basipodite P1 with a long spine,
not reaching half the length of Enp3. Enp1P4 with a developed notch on the outer mar-
gin. Enp3P4 2.4 times as long as wide. Inner apical spine 0.77 times as long as segment
and 1.03 times as long as outer spine. Outer lateral spine situated at 0.77 of the seg-
ment length.
P5 consisting of 2 segments. Basal segment with long outer seta. Free segment with
long apical seta and short inner subapical spine (fig. 17).
Genital segment broadly rounded in its anterior part (fig. 17). Seminal receptacle
similar to that of A. robustus, with notched anterior margin, but anterior and posterior
parts more rounded.
Anal segment with spinules (larger on ventral side) on its distal margin.
Proctodeum with a single row of setules on either side (fig. 19).
Furcal rami parallel, 4.5 times as long as wide, without hairs on inner margin but
usually covered by tiny spinules. Implantation of Te provided with spinules.
Implantation of Me without spinules (fig. 18–19). Tme bearing short setules along dis-
tal half of its length. Ti bearing long setules on most of its length and shorter setules
on its last quarter. Ti 0.90 times as long as furcal rami. Ti/Tmi = 0.20; Ti/Tme = 0.31;
Ti/Te = 1.8; Ti/Sd = 1.6.
Ma l e. Length (furcal setae excluded): 850–1250 mkm (n = 11).
Antennule with three aesthetascs on segment 1, one aesthetasc on segment 4, and
one aesthetasc on segment 8 (fig. 20).
Antenna with third segment bearing 8 setae (fig. 21).
P1–P5 segmentation and armature identical to those of female. Apical spines of
Enp3P4 relatively longer than in female (fig. 22). P6 with inner spine longer than the
middle seta and shorter than outer seta (fig. 23).
Furcal rami relatively shorter than in female, 3.8–5.7 times as long as wide.
Implantation of Me and Te provided with spinules (fig. 24).
V a r i a b i l i t y. Measurements of specimens from different populations are given in
table 1.
32 I. M. Mirabdullayev, D. Defaye
Fig. 17–19. Acanthocyclops einslei, holotype, } (Germany. MNHN–Cp800): 17 — last thoracic and genital
somites; 18 — furca, ventral side; 19 — furca, dorsal side. Scale bar 100 mkm.
Ðèñ. 17–19. Acanthocyclops einslei, ãîëîòèï, } (Ãåðìàíèÿ. MNHN–Cp800): 17 — ïîñëåäíèé òîðàêàëü-
íûé è ãåíèòàëüíûé ñåãìåíòû; 18 — ôóðêà, âåíòðàëüíî; 19 — ôóðêà, äîðñàëüíî. Ìàñøòàáíàÿ ëèíåéêà
100 ìêì.
Body l e n g t h. 1200–1800 mkm (n = 67). Length ratio of two apicalmost spines
of maxilliped 1.3–1.8. Enp3P4 L/W = 2.0–2.7. Inner apical spine 0.6–0.8 times as long
as segment and usually 1.00–1.05 times as long as outer spine. Outer lateral spine
(sometimes a seta) situated at 0.70–0.80 of the segment length. Furcal rami 4.2–6.4
times as long as wide. Ti 0.75–0.95 times as long as furcal rami. Ti/Tmi = 0.18–0.25;
Ti/Tme = 0.28–0.35; Ti/Te = 1.5–2.0; Ti/Sd = 1.5–1.9. Apical furcal setae (Tmi and
Tme) can bear long setules along most of their length or short setules on only distal
half. Enp3P4 usually bears 3 spines.
D i f f e r e n t i a l d i a g no s i s. Acanthocyclops einslei sp. n. differs from most
species of the Acanthocyclops vernalis-robustus species-complex, including from the
species described above, by the shape of Enp3P4, and the complete absence of
ornamentation on intercoxal plates of P1. Acanthocyclops einslei sp. n. differs from the
closest species, A. brevispinosus by the pattern of ornamentation of the proctodeum,
the relatively shorter apical spines of Enp3P4 and the relatively longer inner apical fur-
cal seta. It differs from A. trajani sp. n. by the absence of spinules on inner side of the
claw-like seta of the basipodite of the maxilla, the length ratio of the apicalmost setae
of the maxilliped and the length ratio Ti/Tmi and Ti/Tme. It differs from A. robustus
by the absence of spinules near the exopodite-seta of basipodite of antenna and by the
relatively shorter Ti.
D i s t r i b u t i o n. Acanthocyclops einslei sp. n. inhabits waterbodies of Eurasia (not
recorded in Scandinavia) and North America.
E co l o g y. Acanthocyclops einslei sp. n. prefers polluted pools, ditches and small
ponds poor in phytoplankton. It can also be found in the littoral zone of lakes. In North
America, it sometimes co-occurs with A. robustus. In France (pond in vicinity of Paris)
and in Kazakhstan (fishpond), the species was co-occurred with Acanthocyclops trajani.
E t ymo l o g y. Named in honour of the late Dr U. Einsle for his contributions to
our knowledge of Acanthocyclops systematics.
33On the Taxonomy of the Acanthocyclops robustus Species-Complex…
Fig. 20–24. Acanthocyclops einslei, allotype, { (Germany. MNHN–Cp800): 20 — antennule; 21 — third
segment of antenna; 22 — Enp3P4; 23 — P6; 24 — furca. Scale bar 50 mkm except 23 — 10 mkm.
Ðèñ. 20–24. Acanthocyclops einslei, àëëîòèï, { (Ãåðìàíèÿ. MNHN–Cp800): 20 — àíòåííóëà; 21 —
òðåòèé ÷ëåíèê àíòåííû; 22 — ýíäîïîäèò P4; 23 — P6; 24 — ôóðêà. Ìàñøòàáíàÿ ëèíåéêà 50 ìêì,
èñêëþ÷àÿ 23 — 10 ìêì.
Discussion
The species described above appear to be very close, but by using additional char-
acters shown to be constant in the female (length ratio of the apicalmost setae of the
endopodite of the maxilliped, ornamentation of the claw-like seta of basipodite of max-
illa, level of insertion of the outer seta/spine of Enp3P4), in combination with the other
characters previoulsy used, it is possible to characterize each taxon.
T. Petkovski (1975) already had enough data to distinguish A. trajani as a separate
species. Dussart (1967) also saw clear differences in shape of Enp3P4 of specimens
from France. However, B. Dussart (pers. comm.) also discussed this problem with
F. Kiefer. The latter examined large number of specimens from many geographic ori-
gins, but could not diagnose a separate species on the basis of the characters he stud-
ied, particularly in view of the variability of Enp3P4 and the overlapping of indices
(Enp3P4 Int. sp./L; Int. sp./W) (Kiefer, 1976). The present study of microcharacters,
added to the morphological measurements (table 2), has allowed us to separate the dif-
ferent taxa and define the two new species, A. trajani sp. n. and A. einslei sp. n.
A. trajani sp. n. corresponds to A. americanus sensu Lowndes (1926), Rylov
(1948), V. I. Monchenko (1961, 1974), B. Dussart (1969) and V. R. Alekseev (1995).
Marsh’s types of A. americanus from Wisconsin appear to be lost. Prof. F. Kiefer stud-
ied 3 samples from the US National Museum from other localities (Kansas, Alaska),
determined by Marsh as A. americanus. F. Kiefer (1976) recognised 2 different species
* n = 10 except France n = 4.
34 I. M. Mirabdullayev, D. Defaye
Ta b l e 1. Measurements of Acanthocyclops einslei (adult females)*
Ò à á ëèö à 1. Ðàçìåðû Acanthocyclops einslei (âçðîñëûå ñàìêè)
Body length,
mkm
1282
1200–1400
1196
1165–1275
1683
1500–1850
1180
1125–1200
1800
1800–1800
Fu L/W 4.94
4.45–5.50
4.40
4.15–4.55
5.62
5.00–6.40
4.73
4.25–5.20
5.60
5.25–6.20
Ti/Fu L 0.81
0.74–0.90
0.86
0.80–0.90
0.77
0.73–0.82
0.82
0.72–0.90
0.76
0.75–0.76
Ti/Tmi 0.19
0.18–0.19 0
19
0.18–0.21
0.21
0.20–0.23
21
0.21–0.23
0.21
0.19–0.22
Ti/Tme 0.30
0.28–0.33
0.30
0.28–0.33
0.30
0.28–0.32
0.31
0.28–0.34
0.29
0.28–0.29
S1/Te 1.77
1.64–1.87
1.77
1.65–1.95
1.65
1.57–1.76
1.80
1.56–2.09
1.48
1.46–1.50
Ti/Sd 1.75
1.61–1.87
1.79
1.65–2.04
1.74
1.63–1.87
1.81
1.62–2.05
1.78
1.78–1.78
Mxp ap. set.
ratio
1.51
1.40–1.60
1.48
1.20–1.65
1.52
1.31–1.62
1.39
1.30–1.71
1.46
1.33–1.65
Enp3P4:
L/W 2.43
2.30–2.60
2.16
2.05–2.25
2.16
2.00–2.50
2.41
2.13–2.60
2.26
2.14–2.42
Inn. sp./L 0.75
0.65–0.80
0.74
0.69–0.79
0.75
0.70–0.82
0.71
0.66–0.80
0.71
0.62–0.76
Inn. sp./W 1.80
1.69–1.92
1.62
1.53–1.77
1.62
1.40–1.72
1.70
1.58–1.83
1.61
1.44–1.74
Inn.
sp./outer sp.
1.05
1.00–1.15
1.00
0.98–1.05
1.04
0.97–1.10
1.03
0.98–1.05
1.04
1.00–1.10
Lat. set.
position
0.80
0.75–0.82
0.78
0.75–0.80
0.75
0.73–0.77
0.78
0.76–0.83
0.77
0.76–0.78
Measurement
Germany, Olden-
burg, Wechloy
x
min–max
Yugoslavia, Mon-
tenegro
x
min–max
Uzbekistan, Khalka-
bad, pond
x
min–max
Canada, Waterloo,
Ontario
x
min–max
France, Creteil,
x
min–max
in these samples which he identified as A. robustus and A. vernalis. F. Kiefer therefore
rejected the name "americanus", synonymising it partly with A. robustus, and partly with
A. vernalis. We also checked three samples originally identified by Marsh as A. ameri-
canus from the same museum in Washington, all labelled as A. robustus. We have found
4 different species in these samples that we identified as A. trajani sp. n., A. einslei sp. n.,
A. brevispinosus and A. vernalis. Acanthocyclops. trajani sp. n. had been determined by
Marsh as "americanus".
The original description of A. americanus is very succinct according to the standards
of modern taxonomy. From Marsh’s (1893) figures, (Plate IV, fig. 8–10), P4 can be sup-
posed to be that of A. vernalis (inner apical spine is shorter than outer and is only about
1.20 of width and 0.55 of length of Enp3P4). The genital segment, however, is shown
with rounded lateral sides, but as F. Kiefer (1976) suggested, it is possible that this is an
artefact caused by flattening of the specimen by the cover glass. Consequently, it is pos-
sible that the first description of A. americanus by Marsh corresponds to A. vernalis.
We consider the four species studied here as belonging to the Acanthocyclops robus-
tus species-complex. Females share the common characters of the segmentation and
armature of the antennule; the general pattern of the ornamentation of basipodite of the
antenna (two small separate rows of spinules on caudal side, one basolateral on frontal
side) and the number of setae on the third segment of antenna; the general pattern of
the other buccal appendages; the general segmentation of natatory legs and P5; the shape
of the genital double somite. Males share the segmentation and armature of the anten-
nule, the armature of furca including the spinules at the implantation of Me and Te.
The main traits separating the species are as follows:
Acanthocyclops robustus is the only species of this group to possess a group of spin-
ules on the apical inner margin of the basipodite of the antenna. A. trajani sp. n. and
A. einslei sp. n. are the only species possessing denticulation on the claw-like seta of the
basipodite of maxilla, A. trajani always on both sides and A. einslei never on the inner
side, but they differ, for example, by the site of insertion of the outer seta/spine on
Enp3P4. Acanthocyclops brevispinosus differs from its congeners by the patchy pattern of
setation of the proctodeum and by the absence of ornamentation on the intercoxal plates
of P1 to P3. It also differs from its closest relative — A. einslei by the shorter Ti, the longer
apical spines of Enp3P4 and the shorter setae of Enp3P4. A. trajani also differs from all
species mentioned, by the ornamentation of the antenna, the length ratio of the two api-
35On the Taxonomy of the Acanthocyclops robustus Species-Complex…
Ta b l e. 2. Comparison of biometrics of species of the Acantocyclops robustus species-complex
Òà á ëèö à 2. Ñðàâíåíèå áèîìåòðè÷åñêèõ ïîêàçàòåëåé âèäîâ êîìïëåêñà Acantocyclops robustus
Body length, mkm 1025–1215 1025–1600 165–1800 1200–1230
Fu L/W 4.00–5.45 4.15–5.80 4.15–6.40 5.20–6.85
S1/ Fu 0.55–0.79 0.81–1.04 0.73–0.94 0.39–0.48
S1/s2 0.15–0.19 0.23–0.29 0.18–0.25 0.12–0.16
S1/s3 0.26–0.32 0.34–0.42 0.28–0.35 0.18–0.21
S1/s4 1.24–1.68 1.45–2.20 1.46–2.00 0.94–1.32
S1/s5 1.20–1.50 1.45–1.80 1.48–1.95 0.80–1.05
Mxp ap. set. ratio 1.18–1.33 1.70–2.25 1.20–1.80 1.55–1.80
Enp3P4:
L/W 2.05–2.67 2.25–3.10 2.00–2.60 2.20–2.50
Inn. sp. /L 0.71–0.93 0.77–0.96 0.62–0.82 0.76–0.95
Inn. sp. /W 1.71–2.15 1.87–2.46 1.45–1.90 1.75–2.25
Inn. sp./out. sp. 0.99–1.13 1.04–1.29 0.97–1.15 0.90–1.00
Lat. set. position 0.62–0.71 0.55–0.66 0.69–0.82 0.71–0.80
Biometric A. robustus A. trajani A. einslei A. brevispinosus
calmost setae of maxilliped, the armament of inner claw-like spine of the basipodite of
maxilla, and often by the presence of ornamentation on intercoxal plates of P2 and P3.
The validity of these species is strongly supported by the set of morphological char-
acters used in this study, but complementary studies, as cytogenetics (in preparation)
should be useful in testing this approach to the taxonomy of species-complexes.
Key to species of the Acanthocyclops robustus species-complex (females)
Òàáëèöà äëÿ îïðåäåëåíèÿ êîìïëåêñà âèäîâ Acanthocyclops robustus (ñàìêè)
1. Basipodite of antenna with spinules near exopodite-seta. ………….........…… A. robustus (G. O. Sars, 1863)
— Basipodite of antenna without spinules near exopodite-seta. ………………………...........................………….. 2
2. Implantation of lateral seta/spina of Enp3P4 at 0.55–0.65 of length of the segment. …..… A. trajani sp. n.
— Implantation of lateral seta/spina of Enp3P4 at 0.70–0.80 of length of the segment. ……….……............. 3
3. Setules near anal opening in 2 patches; Ti shorter than 1/2 length of furca, no spinules on the furcal rami.
......…...………............................................................................................ A. brevispinosus (Herrick, 1884)
— Setules near anal opening in 2 rows; Ti longer than 3/4 length of furca, tiny spinules on the furcal rami.
……………….....….................................................................................................................. A. einslei sp. n.
Prof. B. Dussart and Dr. J. W. Reid are thanked for helpful suggestions. Drs. V. Alekseev (St.-
Petersburg), H.-U. Dahms (Oldenburg), F. Fiers (Brussels), M. Holynska (Warsawa), T. Karanovic
(Bellizzi), K. Kawabata (Kanazawa), E. Krupa (Almaty), F. Lescher-Moutoue (Paris), J. W. Reid (Washin-
gton), T. S. Stuge (Almaty) are thanked for providing comparative material. Dr. H.-W. Mittmann (Karlsru-
he) is thanked for help in working with F. Kiefer’s collection, Dr. T. Glatzel (Oldenburg) is thanked for help
with U. Einsle’s collection. We are much indebted to Mrs. I. Wilhelmsen (Oslo) and Dr. T. C. Walter
(Washington) for providing us specimens from G. O. Sars’s and D. Marsh’s collections. IMM is very grateful
to the Deutscher Akademisher Austauschdienst, Smithsonian Institution, the Royal Society (London), the
Museum National d’Histoire Naturelle (Paris), the University of Ghent and the Royal Belgian Institute of
Natural Sciences for supporting this study. We are grateful to Mark Judson (MNHN, Paris) for correcting
the English text.
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37On the Taxonomy of the Acanthocyclops robustus Species-Complex…
|
| id | nasplib_isofts_kiev_ua-123456789-3361 |
| institution | Digital Library of Periodicals of National Academy of Sciences of Ukraine |
| issn | 0084-5604 |
| language | English |
| last_indexed | 2025-11-28T16:42:38Z |
| publishDate | 2004 |
| publisher | Інститут зоології ім. І. І. Шмальгаузена НАН України |
| record_format | dspace |
| spelling | Mirabdullayev, I.M. Defaye, D. 2009-07-07T09:07:09Z 2009-07-07T09:07:09Z 2004 On the Taxonomy of the Acanthocyclops robustus Species-Complex (Copepoda, Cyclopidae): Acanthocyclops brevispinosus and A. einslei sp. n / I. M. Mirabdullayev, D. Defaye // Вестн. зоологии. — 2004. — Т. 38, № 5. — С. 27-37. — англ. 0084-5604 https://nasplib.isofts.kiev.ua/handle/123456789/3361 595.34 Приведены новые сведения по морфологии Acanthocyclops brevispinosus (Herrick, 1884). Вид, ранее ошибочно идентифицировавшийся как A. robustus (sensu Petkovski, 1975; Kiefer, 1976; Einsle, 1997 и др.), описан в качестве нового вида A. einslei Mirabdullayev & Defaye, sp. n. Приведены данные по распространению и изменчивости. New data on morphology of Acanthocyclops brevispinosus (Herrick, 1884) are provided. A. einslei Mirabdullayev & Defaye, sp. n., previously misidentified as (sensu Petkovski, 1975; Kiefer, 1976; Einsle, 1997 et al.) is described. en Інститут зоології ім. І. І. Шмальгаузена НАН України Фауна и систематика On the Taxonomy of the Acanthocyclops robustus Species-Complex (Copepoda, Cyclopidae): Acanthocyclops brevispinosus and A. einslei sp. n Таксономия комплекса видов Acanthocyclops robustus (Copepoda, Cyclopidae): Acanthocyclops brevispinosus и A. einslei sp. n Article published earlier |
| spellingShingle | On the Taxonomy of the Acanthocyclops robustus Species-Complex (Copepoda, Cyclopidae): Acanthocyclops brevispinosus and A. einslei sp. n Mirabdullayev, I.M. Defaye, D. Фауна и систематика |
| title | On the Taxonomy of the Acanthocyclops robustus Species-Complex (Copepoda, Cyclopidae): Acanthocyclops brevispinosus and A. einslei sp. n |
| title_alt | Таксономия комплекса видов Acanthocyclops robustus (Copepoda, Cyclopidae): Acanthocyclops brevispinosus и A. einslei sp. n |
| title_full | On the Taxonomy of the Acanthocyclops robustus Species-Complex (Copepoda, Cyclopidae): Acanthocyclops brevispinosus and A. einslei sp. n |
| title_fullStr | On the Taxonomy of the Acanthocyclops robustus Species-Complex (Copepoda, Cyclopidae): Acanthocyclops brevispinosus and A. einslei sp. n |
| title_full_unstemmed | On the Taxonomy of the Acanthocyclops robustus Species-Complex (Copepoda, Cyclopidae): Acanthocyclops brevispinosus and A. einslei sp. n |
| title_short | On the Taxonomy of the Acanthocyclops robustus Species-Complex (Copepoda, Cyclopidae): Acanthocyclops brevispinosus and A. einslei sp. n |
| title_sort | on the taxonomy of the acanthocyclops robustus species-complex (copepoda, cyclopidae): acanthocyclops brevispinosus and a. einslei sp. n |
| topic | Фауна и систематика |
| topic_facet | Фауна и систематика |
| url | https://nasplib.isofts.kiev.ua/handle/123456789/3361 |
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