Content uploaded by Allart Van Viersen
Author content
All content in this area was uploaded by Allart Van Viersen
Content may be subject to copyright.
eschweizerbartxxx sng-
63
Senckenbergiana lethaea 86 (1) 63–75 1 text-fig., 3 pls Frankfurt am Main, 30.06. 2006
New Middle Devonian trilobites from Vireux-Molhain (Ardennes, northern France)
With 1 Text-figure and 3 Plates
AllArt PhiliP vAn viersen
Abstract
Lower Eifelian (Middle Devonian) strata cropping out in the vicinity of Vireux-Molhain, Ardennes,
France, have yielded a rich trilobite fauna. Four trilobite species are recorded, namely Ceratarges cogna-
tus n. sp., Rhenocynproetus catervus n. sp., Cyphaspis n. sp. A and Thysanopeltella (Septimopeltis) mag-
nispina (MAillieux 1938). Ceratarges cognatus n. sp. is regarded as a possible transitional form between
Ceratarges faouensis MorzAdec 1969 from the Massif armoricain and stratigraphically younger species
from the Rhenohercynian.
K ey wo rd s: Trilobita, taxonomy, Devonian, Ardennes, France.
Kurzfassung
Die in dem Gebiet um Vireux-Molhain, Ardennen, Frankreich anstehenden Schichten des unteren Eife-
lium (Mittel Devon) haben eine reiche Trilobitenfauna erbracht. Vier Trilobitenarten werden beschrieben,
nämlich Ceratarges cognatus n. sp., Rhenocynproetus catervus n. sp., Cyphaspis n. sp. A und Thysan-
opeltella (Septimopeltis) magnispina (MAillieux 1938). In Ceratarges cognatus n. sp. wird eine mögli-
cherweise bestehende Übergangsform zwischen Ceratarges faouensis MorzAdec 1969 aus dem Massif
armoricain und stratigraphisch jüngeren Arten aus dem Rhenohercynikum gesehen.
Author’s address: Allart Philip van Viersen, Graaf van Loonstraat 25; NL-6121 JS Born, The Netherlands. E-mail: apvanviersen@hotmail.com
Introduction
The ‘Mur des douaniers’, a Middle Devonian fossil locality
near the north-eastern French town of Vireux-Molhain has be-
come famous for the fully articulated trilobites that frequently
occur there. Digging was conducted extensively until in the
mid 1990’s, when authorities prohibited further collecting
at this site. Despite their fame, trilobites from the ‘Mur des
douaniers’ are very poorly documented; the majority never
having been properly described. This has resulted in a number
of unfortunate adoptions of species names from other locali-
ties, in particular from the Middle Eifelian ‘Trilobiten Felder’
(Trilobite fields) near Gees, German Eifel, in which inconsist-
ent morphology and age of the specimens were overlooked.
The present paper is the first part in a review of the trilobite
taxa that occur at the ‘Mur des douaniers’, dealing with the
genera Ceratarges, Cyphaspis, Rhenocynproetus and Thysan-
opeltella.
As far as an overview is available on the examined mate-
rial, the composition of the trilobite fauna is not very different
from that of Early Eifelian trilobite faunas from the Ardennes
and Eifel. It includes representatives of Cornuproetus (Cornu-
proetus), Cyphaspis, Geesops, Leonaspis (sensu rAMsköld &
chAtterton 1991), Pedinopariops (Pedinopariops) and Scab-
riscutellum, among others. The occurrence of Thysanopeltella
(Septimopeltis) at the ‘Mur des douaniers’ however, is con-
spicuous. In the Rhenohercynian, this subgenus is known only
from the French Ardennes and German Sauerland, with no
evidence available at this point of its occurrence in the Belgian
Ardennes and German Eifel.
© E. Schweizerbart’sche Verlagsbuchhandlung (Nägele u. Obermiller), 2006, ISSN 0037-2110
eschweizerbartxxx sng-
vAn viersen: New Middle Devonian trilobites from Vireux-Molhain (Ardennes, northern France)64
Locality and age
The material that was studied comprises about 1,500 trilobites
that have been collected in the late 1970s and early 1980s at
the ‘Mur des douaniers’. The site is a road cut near the Bel-
gian-French border, just northwest of the town of Vireux-Mol-
hain, Ardennes, France (text-fig. 1). The exposed rock section
was traditionally assigned to the ‘Assise de Bure’ and is con-
sidered to be of Early Eifelian age (Polygnathus costatus cos-
tatus Biozone) after schrAut (2000), based on the occurrence
of the goniatite Pinacites jugleri. Consequently, the outcrops
may be assigned to the basal part of the Jemelle Formation
(Bultynck et al. 2000; Bultynck & dejonghe 2001).
In general, trilobite material from the ‘Mur des douani-
ers’ is characterised by severely deformed, articulated internal
moulds whereas specimens with shell preservation are excep-
tions. External moulds were found but usually not taken from
the site and consequently only scant material is available to
make casts of. Geesops sparsinodosus gallicus struve 1982
(see pl. 3 fig. 4) is the dominant taxon by far, comprising
more than half of the examined material. schrAut (2000) il-
lustrated both a reconstruction and a rare specimen of this
subspecies with the shell preserved. The other phacopine at
this locality, Pedinopariops (Pedinopariops) sp., is much rarer
as was noticed by struve (1982), and the two occur at a ratio
of about 10:1. Rhenocynproetus catervus n. sp. comprises at
least one third of the material that was examined, and articu-
lated remains of this species frequently occur ‘en mass’ in thin
(maximally several centimetres thick) rock layers. Lichidae are
very rare, and seem to be represented here only by Ceratarges
cognatus n. sp.
Acknowledgements
j.W.M. jAgt (Natuurhistorisch Museum Maastricht) and
B. schoeneMAnn (Paläontologisches Institut der Universi-
tät Bonn) have reviewed an earlier draft. M. BAsse (Bo-
chum), R. Feist (Université Montpellier II) and A. lord (For-
schungsinstitut Senckenberg) kindly reviewed the manuscript.
A. kWAntes and M.C. vAn de Wiel (Natuurmuseum Brabant)
have provided access to the material that is described in this
paper. r. sPeijer and s. goolAerts (both Katholieke Univer-
siteit Leuven) and d. leluBre (Strépy-Bracquegnies) have
provided access to additional trilobite material for comparison.
G. dAuMeries (Gilly) has helped improve the manuscript. I am
indebted to these persons for their help.
Text-fig. 1. Map showing area around Vireux-Molhain and the fossil site ‘Mur des douaniers’, marked by cross.
eschweizerbartxxx sng-
vAn viersen: New Middle Devonian trilobites from Vireux-Molhain (Ardennes, northern France)65
Systematic paleontology
The material that is described and figured in this paper is housed in the
collections of the Natuurmuseum Brabant, Tilburg, The Netherlands
(NH641). One specimen in the collection of the Institut royal des Sci-
ences naturelles de Belgique, Brussels (I.G.), is also referred to.
Morphologic terminology used follows thoMAs & holloWAy
(1988), Whittington & kelly in kAesler (1997) and eBAch &
Ahyong (2001).
Family Lichidae hAWle & cordA 1847
Subfamily T ro c h u r i n a e Phleger 1936
Genus Ceratarges gürich 1901
Type species: Arges armatus goldFuss 1839.
O t h e r s p e ci es (only western Europe): Ceratarges berolinensis
(richter 1909), Ceratarges faouensis MorzAdec 1969, Ceratarges
bergicus BAsse in BAsse & Müller 2004, Ceratarges cognatus n. sp.
Ceratarges cognatus n. sp.
Pl. 1 figs 1-6
? e.p. 1938 Ceratarges armatus (goldF.) – MAillieux: 27 [non
Co2c].
E t y m o l o gy : Latin adjective: cognatus = related by birth (to
faouensis).
H o l o t y p e : Internal mould of partial thoracopygidium, NH641
52.265, pl. 1 fig. 1.
Ty p e l o c a l i t y : ‘Mur des douaniers’, Vireux-Molhain, Ardennes,
France.
Ty p e s t r a t u m : Jemelle Formation (Lower Eifelian), Polygnathus
costatus costatus Biozone.
P ar at yp es : Internal mould of partial cephalothorax, NH641
52.270; internal mould of pygidium, NH641 52.266. All from type
locality.
D i a g no s i s : A species of Ceratarges with the following
characteristic features: pygidium only slightly wider (tr.) than
long (sag.); rachis comparatively long, measuring between 0.8
and 0.9 of sagittal pygidial length, cylindrically shaped, termi-
nated bluntly; height of rachis in lateral view comparatively
uniform, somewhat increased around basis of dorsal spine; ra-
chis with a single dorsal spine positioned between 0.6 and 0.7
of sagittal pygidial length.
D e s c ri p t i o n : Cephalon deformed in all specimens; as
far as it is preserved it conforms to the generic diagnosis by
thoMAs & holloWAy (1988) and is not distinctly different
from the cephalon of Ceratarges armatus. It is possible that
the longitudinal glabellar furrows are less divergent near the
anterior border than those in Ceratarges armatus, which is
suggested by the study of several of the cephala. However,
additional material is needed to corroborate these observa-
tions. Thorax: Rachis cylindrically vaulted, subsemi-circular
in section view (tr.); pleural ribs as thick (exsag.) as pleural
spines. Pygidium (dorsal view): pygidial outline slightly wider
(tr.) than long (sag.), sagitally and exsagitally convex; rachis
cylinder-shaped; length (sag.) of rachis between 0.8 and 0.9
of sagittal pygidial length; basis of a dorsal spine present on
posterior part of rachis, positioned between 0.6 and 0.7 of
sagittal pygidial length; area on rachis around dorsal spine
swollen bladder-like; pleural field bearing three prominent ribs
that extend into major border spines; first pleural rib (count-
ing from the anterior) weakly curved posteriorly towards the
lateral border, extended into a smoothly, somewhat ventrally
and posteriorly angled major border spine; second pleural rib
directed close to transversally, at a less than 90 degrees angle
from pygidial sagittal line, remaining straight over its entire
length until reaching pygidial margin, then extended into a
weakly dorsally oriented, major border spine; third pleural rib
starting near half-way rachis, proximally exsagittally, distally
slightly more abaxially oriented; secondary pygidial marginal
spines comparatively long (length of one the spines in the ex-
amined material exceeding width (tr.) of pleural field, see pl. 1
fig. 2b); postaxial field conspicuously short (sag. and exsag.);
bifid postaxial ridge hardly visible. Pygidium (lateral view):
height of rachis uniform in anterior part, somewhat increased
near dorsal spine, then returning to usual height before drop-
ping progressively towards postaxial field. Pygidium (poste-
rior view): prominent axial ring with semicircular to possibly,
slightly convex contour; rachis semicircular in outline, its
maximum height significantly greater than that of pleural field;
second pleural rib slightly higher than first and third.
O r na m e n t : Several granule pairs are visible on the py-
gidial rachis of the holotype, anterior to the dorsal spine. The
surface of this area is, however, only moderately preserved in
the majority of specimens. In several pygidia, a single, large
granule is visible halfway along the second and third pleural
ribs, as can also be observed in Ceratarges armatus.
D e f o r m a t i on : The morphology of this species in
the ‘Mur des douaniers’ material can be severely affected by
tectonic deformation. The pygidial rachis may be somewhat
constricted (tr.) near the second pleural rib pair, which is par-
ticularly the case in larger specimens (cf. pl. 1 fig. 2a). Severe
dorsal flattening of the pygidium can lead to an outstretched
rachis, with the dorsal spine positioned somewhat more ante-
riorly (cf. pl. 1 figs 3a-b). The posterior margin of the pygidial
rachis can vary from almost square-shaped to rounded, occa-
sionally even convex. The least distorted pygidia show that,
characteristically, the rachis is rather bluntly terminated, its
posterior margin being slightly rounded.
D i s c us s i o n : Morphologically close is Ceratarges faouen-
sis from the Upper Emsian of the Massif armoricain, France.
Unfortunately, only two internal moulds of pygidia are known
of that species which impedes a detailed comparison with
the new species. Nevertheless, it is possible to detect several
unique similarities between both species: the rather posteri-
orly positioned larger dorsal spine on the pygidial rachis; the
comparatively long (sag.) rachis in relation to the pygidial
length (sag.); the strong vaultation of the rachis (cf. MorzAdec
1983: pl. 31 fig. 6b). It is tentatively suggested here, that these
observations may indicate that the Early Eifelian Ceratarges
cognatus n. sp. has descended from the Late Emsian Cera-
targes faouensis and, possibly, has subsequently given rise to
stratigraphically younger species of the genus in the Rheno-
hercynian. In favour of the latter the following point can be
added. According to BAsse in BAsse & Müller (2004: 106),
Moroccan Ceratarges are generally distinguishable from rhen-
ish Ceratarges by their thinner (exsag.) thoracic pleural spines
compared to the thickness (exsag.) of the thoracic pleurae.
The well developed pleural spines of Ceratarges cognatus n.
eschweizerbartxxx sng-
vAn viersen: New Middle Devonian trilobites from Vireux-Molhain (Ardennes, northern France)66
sp. are similar to those typically found in rhenish Ceratarges
and clearly different from Moroccan Ceratarges. However, it
should be stressed that little is known about this genus in Mo-
rocco, from where most specimens lack associated data about
exact provenance and age. In addition, the cephalon and thorax
of Ceratarges faouensis remain unknown.
C o m p ar i s o n s : The new species has been confused in the
past with Ceratarges armatus, which is known from the Mid-
dle Eifelian of the Eifel (richter & richter 1917, BAsse in
BAsse & Müller 2004, among others) and Belgian Ardennes
(MAillieux 1904, 1912, therein erroneously identified as “Aci-
daspis vesiculosa” according to richter & richter 1917: 54;
vAn viersen, in preparation). The pygidium of the new species
is readily distinguished from that of the type species by its
smaller (tr.) outline: only slightly wider (tr.) than long (sag.) in
the new species, whereas clearly wider than long in the other;
the significantly longer rachis and shorter postaxial field; the
cylindrical shape of the rachis, whereas it is weakly vaulted
in Ceratarges armatus; the more or less uniform height of the
rachis in lateral view; the position of the dorsal spine on the
rachis: between 0.4 and 0.5 of sagittal pygidial length in Cera-
targes armatus, as against between 0.6 and 0.7 in the new spe-
cies; the weakly developed bifid postaxial ridge in the present
species, which is clearly present in Ceratarges armatus.
The pygidium of Ceratarges faouensis is principally differ-
ent from that of the new species in having a rachis with: much
more numerous granules, both a large dorsal spine and a spine
or tubercle just posterior of it (MorzAdec 1983: 151), a slightly
concave posterior margin.
Family Proetidae sAlter 1864
Subfamily P r o e t i n a e sAlter 1864
Genus Rhenocynproetus BAsse 2002
Type species: Devonoproetus doernbergensis BAsse 1996.
Rhenocynproetus catervus n. sp.
Pl. 2 figs 1-8
E t y m o l o gy : Latin noun: caterva (f) = crowd, after the mass oc-
currences of articulated carapaces of this species at its type locality.
H o l o t y p e : Articulated specimen with shell preservation, NH641
52.272, pl. 2 fig. 2.
Ty p e l o c a l i t y : ‘Mur des douaniers’, Vireux-Molhain, Ardennes,
France.
Ty p e s t r a t u m : Jemelle Formation (Lower Eifelian), Polygnathus
costatus costatus Biozone.
P ar at yp e s : Internal mould of articulated specimen, NH641
52.277; external mould of articulated specimen with plaster cast
NH641 52.273; internal mould of articulated specimen, NH641
52.274. All from type locality.
D i a g no s i s : A species of Rhenocynproetus with the fol-
lowing characteristic features: anterior part of glabella steeply
inclined towards the cephalic border in lateral view, partially
overhanging it; genal corner sharp, not prolonged into thorn or
spine; surface of librigenal field rough, without granulation.
D e s c r i pt i o n : Cephalon (dorsal view): outline some-
what convexly (sag. and exsag.) rounded; cephalic border
swollen, bearing about four, prominent ridges on outer half;
glabella with convex contour (sag. and exsag.), longer (sag.)
than wide (tr.), overhanging anterior border but usually not
anterior margin; surface of glabella densely covered with gran-
ules; anterior branch of facial suture not particularly divergent;
posterior branch of facial suture near initially exsagitally ori-
ented, then from about half-way (exsag.) strongly bent abaxi-
ally towards . Cephalon (lateral view): cephalon longer than
high; glabellar contour ascending slightly from S0 towards the
anterior, adjacent to its highest point, then slowly descending
before anteriorly dropping quickly in height towards cephalic
border furrow where it partially overhangs cephalic border; eye
socle and subocular ridge prominent; eye positioned lateral of
posterior half of glabella; surface of librigenal field rough. Py-
gidium (dorsal view): widely rounded; axis consisting of seven
rings plus terminal lobe; pleural field bearing five, possibly six
ribs that almost reach pygidial margin; interpleural furrows
visible over entire length of pleural rib.
Va r i at i o n : A narrow, somewhat depressed pygidial bor-
der appears to be present in several specimens with shell preser-
vation (cf. pl. 2 fig. 3) whereas it is absent in other ones (cf. pl. 2
fig. 2c), unrelated to size of the specimens. The taxonomic value
of these features cannot be assessed based only on the few spec-
imens with shell preservation that are available for this study. It
is unlikely that the occurrence of the two slightly different forms
(with or without a depressed pygidial border) at one locality can
be interpreted as evidence for sexual dimorphism.
D e f o r m a t i on : The cephalon, and especially the gla-
bella can be severely affected by tectonic deformation. Usually,
the left or the right librigena is pushed adaxially, in many cases
hidden under the cranidium in dorsal view. Although in many
specimens the glabella is about as long (sag.) as wide (tr.), the
least deformed cranidia (e.g. pl. 2 fig. 8) show that this species
has the characteristic, projectile-shaped glabella that is more or
less similarly found in Rhenocynproetus cultrijugati (richter
& richter 1918) (cf. lütke 1990: pl. 4 fig. 30). The anterior
branch of the facial suture may vary between divergent and
convergent, defined by the strength of deformation.
C o m p ar i s o n s : When compared with the closely related
species Rhenocynproetus cultrijugati from the Lower Eifelian
of the Eifel, the new species is readily distinguished by its an-
teriorly much steeper glabella in lateral view; the absence of a
genal thorn or spine; the absence of granules on the surface of
the librigenal field.
Rhenocynproetus doernbergensis from the Lower Eifelian
of Sauerland is principally different in having a well developed
genal spine which is absent in the new species.
Family Aulacopleuridae Angelin 1854
Subfamily Otarioninae richter & richter 1926
Genus Cyphaspis BurMeister 1843
Type species: Phacops ceratophthalmus goldFuss 1843.
Cyphaspis n. sp. A
Pl. 3 figs 2-7
M a t e r i a l : 5 internal moulds of articulated specimens, NH641
52.283-52.285, 52.286, 52.288; partially exfoliated articulated ce-
eschweizerbartxxx sng-
vAn viersen: New Middle Devonian trilobites from Vireux-Molhain (Ardennes, northern France)67
phalothorax, NH 641 52.287. All from the Jemelle Formation (Lower
Eifelian), Polygnathus costatus costatus Biozone at the ‘Mur des
douaniers’.
D e s c ri p t i o n : Cephalon (dorsal view): Contour of ce-
phalon semicircular to broadly rounded; median glabellar
lobe ovoid to drop-shaped, overhanging preglabellar field, its
surface densely covered with fine granules; librigenal field
comparatively steep, not vertical; posterolateral extremity
of librigenal field more or less lateral (tr.) of L0; genal spine
about as long as sagittal length of entire carapace, faintly
rounded abaxially, distally running smoothly adaxially, always
remaining close to the carapace; L1 small, oblong. Cephalon
(lateral view): median glabellar lobe strongly vaulted, rounded,
occasionally slightly verging to knee-shaped near its middle
(sag.); highest point of median glabellar lobe slightly poste-
rior to its middle (sag.). Thorax: Sixth thoracic spine better
developed and bearing long, posteriorly curved, dorsal spine.
One specimen (pl. 3 fig. 5) is partially exfoliated and shows
the following features: axis not particularly vaulted, near the
cephalon as wide (tr.) as median glabellar lobe; pleural furrow
abaxially becoming broader (exsag.) and deeper; anterior pleu-
ral band initially transversally directed, then near halfway (tr.)
bent knee-like and oriented posterolaterally; posterior pleural
band initially very weakly angled posteriorly, then near half-
way (tr.) strongly bent and oriented posterolaterally. Pygidium:
widely rounded; axis as wide (tr.) as pleural field.
D e f o r m a t i on : Facial sutures have been changed due
to tectonic deformation in the majority of the examined speci-
mens of Cyphaspis from this locality. The anterior branch of
the facial suture is usually hardly curved so that it runs exsag-
itally in dorsal view, from near the eye to the anterior rim. In
other specimens it is possible that the anterior branch is clearly
rounded abaxially, with b positioned halfway (exsag.). The
librigenal field may be vertical or even overhanging, which is
caused exclusively by deformation.
R e m a rk : Although undoubtedly the material of Cyphaspis
from Vireux-Molhain represents a new taxon, it is described
here under open nomenclature because of its limited preserva-
tion. At this point, the only discernible feature of any diagnos-
tic value would be the morphology of the median glabellar
lobe.
C o m p ar i s o n s : The species from the ‘Mur des douaniers’
is distinguished from Cyphaspis balanops (erBen 1953) by
its median glabellar lobe overhanging the preglabellar field in
dorsal view, whereas in Cyphaspis balanops it does not over-
hang the preglabellar field at all; the basally much more con-
stricted (tr.) shape of the median glabellar lobe in dorsal view;
the more posteriorly (exsag.) positioned attachment point of
the genal spine compared to L0.
Cyphaspis unguloides (erBen 1953) is readily distin-
guished from Cyphaspis n. sp. A by its convex (sag. and ex-
sag.) cephalic contour in dorsal view; its median glabellar lobe
which does not overhang the preglabellar field.
Cyphaspis ceratophthalma (goldFuss 1843), with which
the current species has been confused in the past, is clearly dif-
ferent in having a more overhanging, distinctly pointed sack-
shaped median glabellar lobe in lateral view; in the presence
of four large granules on the anterior part of the glabella that
are visible even in internal moulds.
Family Styginidae vogdes 1890
Subfamily Scutelluinae richter & richter 1955
Genus Thysanopeltella koBAyAshi 1957
Type species: Bronteus acanthopeltis BArrAnde 1852.
Subgenus Septimopeltis PŘiByl & vAnĚk 1971
Type species: Bronteus clementinus BArrAnde 1872.
Thysanopeltella (Septimopeltis) magnispina
(MAillieux 1938)
Pl. 2 figs 9-11; pl. 3 fig. 1
* 1938 Thysanopeltis magnispina MAillieux: 55-57, pl. 2 figs 10,
10a-b.
1971
T. (S?) magnispina (MAileAux) (sic) – PŘiByl & vAnĚk: 386.
2004 Septimopeltis magnispina (MAillieux 1938) – BAsse in BAsse
& Müller: pl. 18 fig. 218.
H o l o t y p e : Internal mould of articulated carapace (I.G. 11285),
figured by MAillieux (1938: pl. 2 figs 10, 10a).
Ty p e l oc al it y: According to MAillieux “Vicinity of Treignes”,
which is in Belgium (text-fig. 1). It is unclear if the holotype was col-
lected from the ‘Mur des douaniers’ or actually from Belgium.
Ty p e s t r a tu m: According to MAillieux “Assise de Couvin, ni-
veau Co2a”. Probably Lower Eifelian Jemelle Formation (godeFroid
in Bultynck et al. 1991).
N ew m a t er ia l: 3 internal moulds of articulated specimens,
NH641 52.279-52.281; 1 plaster cast of an articulated specimen,
NH641 52.282. All from the ‘Mur des douaniers’.
D e s c ri p t i o n : Cephalon widely rounded; cephalic border
sharp with weakly upturned border; anterior margin of gla-
bella subelliptical, well marked by shallow preglabellar fur-
row; L0 medially pointed dorsally, not posteriorly; S0 narrow
(sag. and exsag.), groove-like, distally very shallow; S1 and
S2 combined, deep, despite some lateral deformation prob-
ably comparatively narrow (tr.); S3 isolated; palpebral area
and posterior area inflated; axial furrows slightly diverging
near posterior part of glabella, then proportionally diverging
from near S1+S2, somewhat abaxially rounded near L2+L3
and frontal lobe; genal angle pointed, prolonged into a short
thorn. Thorax: axial rings medially pointed; width of axial
lobe comparatively uniform throughout its range; axial furrow
distinct; pleural lobes distally prolonged into posteriorly bend-
ing spines. Pygidium: outline parabolic; width (tr.) exceeding
length (sag.); pygidial ribs convex in section; pygidial me-
dian rib bifurcating at slightly posterior to its sagittal length;
pygidial pleural ribs and bifurcating branches of median rib
distally prolonged into pleural spines; pygidial pleural spines
in alignment with pleural rib pair 1 to 5 (counting from pos-
terior and excluding branches of median rib) not embracing
secondary spines in-between; remaining pleural spines that
are directly associated have a pleural rib all with a secondary
spine of about equal size in-between; total count of pygidial
spines 24; towards posterior of pygidium each spine longer
than the previous.
D e f o r m a t i on : In the least deformed specimens the
pygidial contour is parabolic; typically, it is seemingly sub-
semicircular if a specimen is longitudinally deformed (cf. pl.
eschweizerbartxxx sng-
vAn viersen: New Middle Devonian trilobites from Vireux-Molhain (Ardennes, northern France)68
2 fig. 9). The pygidial rachis is very poorly preserved in all
specimens, its outline ranging from broadly rounded to strong-
ly convex (sag. and exsag.), strongly dependant on degree of
deformation.
C o m p ar i s o n : The cephalon of this subgenus was first
recorded by MAillieux (1938) although in his material it was
severely deformed. Feist (1999) was the first to fully describe
a cranidium that had been collected from Lower Eifelian
strata in the Carnic Alps. The present species is different from
Thysanopeltella (Septimopeltis) carinthiana Feist 1999 in
having anteriorly diverging glabellar axial furrows, as against
parallel in the latter; the medially dorsally pointed L0, which
is posteriorly pointed in the species from the Carnic Alps; the
more anteriorly positioned bifurcation of the median rib; more
numerous pygidial spines.
R e m a rk : As a preliminary note it is mentioned that two
taxa belonging to this subgenus co-occur at the ‘Mur des
douaniers’. The other species, which has numerous second-
ary spines between the pygidial pleural spines (total count of
pygidial spines about ?30), has not been reported before. A
description of the other species will be provided at a later time
since only scant material is available at present.
References
Angelin, N.P. (1854): Palaeontologia Scandinavica. – 1-92; Lipsiae.
BArrAnde, J. (1852): Systême Silurien du centre de la Bohême. Ière
Partie. Recherches paléontologiques, I: Trilobites. – xxx + 935;
Prague & Paris.
BArrAnde, J. (1872): Systême Silurien du centre de la Bohême.
Ière partie. Recherches paléontologiques, I: Trilobites, Crustacés
divers et Poissons (Supplément). – xxx + 647; Prague & Paris.
BAsse, M. (1996): Trilobiten aus mittlerem Devon des Rhenohercyni-
kums: I. Corynexochida und Proetida (1). – Palaeontographica,
(A) 239 (4-6): 89-182.
BAsse, M. (2002): Eifel-Trilobiten 1. Proetida. – 1-152; Korb (Gold-
schneck-Verlag).
BAsse, M. & Müller, P. (2004): Eifel-Trilobiten III. Corynexoch-
ida, Proetida (2), Harpetida, Phacopida (2), Lichida. – 1-261;
Wiebelsheim (Quelle & Meyer-Verlag).
Bultynck, P., coen-AuBert, M. & godeFroid, J. (2000): Summary of
the state of correlation in the Devonian of the Ardennes (Belgium
- NE France) resulting from the decisions of the SDS. – Courier
Forschungsinstitut Senckenberg, 225: 91-114.
Bultynck, P. & dejonghe, L. (2001): Devonian lithostratigraphic units
(Belgium). – Geologica belgica, 4/1-2: 39-69.
BurMeister, P. (1843): Die Organisation der Trilobiten aus ihren le-
benden Verwandten entwickelt; nebst einer systematischen Über-
sicht aller seither beschriebenen Arten. – 1-147; Berlin (Reimer).
eBAch, M.c. & Ahyong, S.T. (2001): Phylogeny of the trilobite subge-
nus Acanthopyge (Lobopyge). – Cladistics, 17: 1-10.
erBen, H.K. (1953): Über einige Otarionidae (Tril.) aus dem Mittel-
Devon der Eifel. – Senckenbergiana lethaea, 34 (1-3): 73-80.
Feist, R. (1999): First Mid-Devonian trilobites from the Carnic Alps.
– Abhandlungen der Geologischen Bundesanstalt, 54: 295-302.
godeFroid, J. (1991): Formation de Jemelle. – In: Bultynck, P., coen-
AuBert, M., dejonghe, l., godeFroid, j., hAnce, l., lAcroix, d.,
PreAt, A., stAinier, P., steeMAns, P., streel, M. & tourneur, F.
Les formations du Dévonien moyen de la Belgique. – Mémoires
pour servir à l’explication des Cartes Géologiques et Minières de
la Belgique, 30: 31-32.
goldFuss, A. (1839): Beiträge zur Familie der fossilen Crustaceen.
– In: Beiträge zur Petrefactenkunde. – Verhandlungen der Kaiser-
lichen Leopoldinisch-Carolinischen Academie der Naturforscher,
19: 353-364.
goldFuss, A. (1843): Systematische Übersicht der Trilobiten und Be-
schreibung einiger neuen Arten derselben. – Neues Jahrbuch für
Mineralogie, Geognosie, Geologie und Petrefaktenkunde, 1843:
537-567.
gürich, G. (1901): Ueber eine neue Lichas-Art aus dem Devon von
Neu-Süd-Wales und über die Gattung Lichas überhaupt. – Neues
Jahrbuch für Mineralogie, Geologie und Paläontologie. Beilage-
Band, 14: 519-539.
hAWle, i. & cordA, A. (1847): Prodrom einer Monographie der böh-
mischen Trilobiten. – Abhandlungen der Königlichen Böhmischen
Gesellschaft der Wissenschaften, 5 (5): 1–176.
koBAyAshi, T. (1957): Notes on two Devonian trilobites from the Ki-
takami Mountains in Japan. – Journal of the Faculty of Science
University of Tokyo, Section 2, 11: 1-10.
lütke, F. (1990): Contributions to a phylogenetical classification of
the subfamily Proetinae sAlter, 1864 (Trilobita). – Senckenber-
giana lethaea, 71 (1-2): 1-83.
MAillieux, E. (1904): Quelques mots sur les trilobites du Couvinien
des environs de Couvin. – Bulletin de la Société belge de Géolo-
gie, de Paléontologie et d’Hydrologie, 17: 579-582.
MAillieux, E. (1912): Texte explicatif du levé géologique de la
planchette de Couvin. – 1-70; Bruxelles (Service géologique de
Belgique).
MAillieux, E. (1938): Le Couvinien de l’Ardenne et ses faunes. – Mé-
moires du Musée royal d’Histoire naturelle de Belgique, 83: 1-57.
MorzAdec, P. (1969): Ceratarges faouensis nov. sp. nouveau trilobite
mésodévonien du Finistère. – Compte rendu sommaire des séanc-
es de la Société Géologique de France, 7: 255-256.
MorzAdec, P. (1983): Trilobites du Dévonien (Emsien-Famennien) de
la Rade de Brest (Massif Armoricain). – Palaeontographica, (A)
181 (4-6): 103-184.
Phleger, F.B. (1936): Lichadian trilobites. – Journal of Paleontology,
10: 593-615.
P
Ř
iByl, A. & vAn
Ě
k, J. (1971): Studie über die Familie Scutelluidae
richter & richter (Trilobita) und ihre phylogenetische Entwick-
lung. – Acta Universitatis Carolinae, Geologica, 4: 361-394.
rAMsköld, L. & chAtterton, B.D.E. (1991): Revision and subdivision
of the polyphyletic ‘Leonaspis’ (Trilobita). – Transactions of the
Royal Society of Edinburgh: Earth Sciences, 82: 333-371.
richter, rud. (1909): Beiträge zur Kenntnis devonischer Trilobiten
aus dem Rheinischen Schiefergebirge. Vorbericht zu einer Mono-
graphie der Trilobiten der Eifel. – Diss.: 1-96; Marburg.
richter, rud. & richter, E. (1917): Die Lichadiden des Eifler De-
vons. – Neues Jahrbuch für Geologie und Paläontologie, 1: 50-72.
richter, rud. & richter, E. (1918): Neue Proetus-Arten aus dem
Eifler Mittel-Devon. – Centralblatt für Mineralogie, Geologie und
Paläontologie, 1918 (3-4): 64-70.
richter, rud. & richter, E. (1926): Die Trilobiten des Oberdevons.
Beiträge zur Kenntnis devonischer Trilobiten. IV. – Abhandlungen
der Preußischen Geologischen Landesanstalt, Neue Folge, 99:
1-314.
richter, rud. & richter, E. (1955): Scutelluidae n.n. (Tril.) durch
„kleine Änderung“ eines Familien-Namens wegen Homonymie.
Antrag an die Internationale Kommission der Zoologischen No-
menklatur. – Senckenbergiana lethaea, 36 (3-4): 291-293.
sAlter, J.W. (1864). A monograph of the British trilobites from the
Cambrian, Silurian and Devonian formations. – Monograph of the
Palaeontographical Society, (1): 1-80.
schrAut, G. (2000): Eine neue Unterart von Phacops (Phacops)
sparsinodosus struve 1970 aus dem Mittel-Devon von Marokko.
– Senckenbergiana lethaea, 80 (2): 525-535.
struve, W. (1982): Neue Untersuchungen über Geesops (Phacopinae;
eschweizerbartxxx sng-
vAn viersen: New Middle Devonian trilobites from Vireux-Molhain (Ardennes, northern France)69
Unter- und Mittel-Devon). – Senckenbergiana lethaea, 63 (5-6):
473-495.
thoMAs, A.t. & holloWAy, D.J. (1988): Classification and phylogeny
of the trilobite order Lichida. – Philosophical transactions of the
Royal Society of London, Series B, 321 (1205): 179-262.
vogdes, A.W. (1890): A bibliography of Paleozoic Crustacea from
1698 to 1889 including a list of North American species and a
systematic arrangement of genera. – United States Geological
Survey, Bulletin, 63: 1-177.
Whittington, h.B. & kelly, S.R.A. (1997): Morphological terms
applied to Trilobita. – In: kAesler, R.L. (Ed.): Treatise on inver-
tebrate paleontology, Part O, Arthropoda 1. Trilobita, revised.
Volume 1: Introduction, Order Agnostida, Order Redlichiida.
– 313-329; Boulder, Colorado & Lawrence, Kansas (Geological
Society of America & University of Kansas Press).
Manuscript submitted: 2005-06-28; accepted: 2006-12-12
eschweizerbartxxx sng-
vAn viersen: New Middle Devonian trilobites from Vireux-Molhain (Ardennes, northern France)70
Plate 1
All specimens from the Jemelle Formation (Lower Eifelian), ‘Mur des douaniers’, Vireux-Molhain, north-
ern France.
Figs 1-6. Ceratarges cognatus n. sp.
1. H ol ot yp e, internal mould of thoracopygidium, NH641 52.265. – a) Dorsal
view, x 2.4; b) lateral view, x 2.8; c) posterior view, x 2.3.
2. Paratype, internal mould of pygidium, NH641 52.266. – a) Dorsal view, x 2.2; b)
lateral view, x 2.8; c) posterior view, x 2.0.
3. Internal mould of articulated specimen, NH641 52.267. – a) Lateral view, x 2.0; b)
dorsal view, x 2.0; c) ventral view on hypostome in situ, x 2.3.
4. Internal mould of partial cephalothorax, NH641 52.268. – Ventral view, close-up of
hypostome, x 2.8.
5. Internal mould of articulated specimen, NH641 52.269. – Lateral view, x 2.7.
6. Paratype, internal mould of partial cephalothorax, NH641 52.270. – a) Ventral view,
x 2.8; b) lateral view, x 2.0; c) dorsal view, x 2.0; d) anterior view, x 2.0.
eschweizerbartxxx sng-
Senckenbergiana lethaea, 86 (1); 2006 Plate 1
A. P. vAn viersen: New Middle Devonian trilobites from Vireux-Molhain (Ardennes, northern France)
eschweizerbartxxx sng-
vAn viersen: New Middle Devonian trilobites from Vireux-Molhain (Ardennes, northern France)72
Plate 2
All specimens from the Jemelle Formation (Lower Eifelian), ‘Mur des douaniers’, Vireux-Molhain, north-
ern France.
Figs 1-8. Rhenocynproetus catervus n. sp.
1. Internal mould of articulated specimen, NH641 52.271. – Lateral view, x 2.7.
2. H o l o t y p e , articulated specimen with shell preservation, NH641 52.272. –
a) Dorsal view on cephalon, x 3.0; b) lateral view, x 3.0; c) dorsal view on pygid-
ium, x 3.0.
3. Paratype, plaster cast of articulated specimen, NH641 52.273. – Dorsal view, x 2.4.
4. Paratype, internal mould of articulated specimen, NH641 52.274. – Lateral view,
x 3.7.
5. Internal mould of articulated specimen, NH641 52.275. – Lateral view, x 3.7.
6. Paratype, internal mould of articulated specimen, NH641 52.277. – a) Dorsal view,
x 3.5; b) lateral view, x 3.8.
7. Partially exfoliated articulated specimen, NH641 52.278. – Oblique lateral view,
x 3.8.
8. Internal mould of articulated specimen, NH641 52.276. – Dorsal view, x 2.9.
Figs 9-11. Thysanopeltella (Septimopeltis) magnispina (MAillieux 1938).
9. Internal mould of articulated specimen, NH641 52.279. – Dorsal view, x 1.4.
10. Internal mould of articulated specimen, NH641 52.280. – Dorsal view, x 2.1.
11. Internal mould of articulated specimen, NH641 52.281. – Dorsal view, x 2.4.
eschweizerbartxxx sng-
Senckenbergiana lethaea, 86 (1); 2006 Plate 2
A. P. vAn viersen: New Middle Devonian trilobites from Vireux-Molhain (Ardennes, northern France)
eschweizerbartxxx sng-
vAn viersen: New Middle Devonian trilobites from Vireux-Molhain (Ardennes, northern France)74
Plate 3
All specimens from the Jemelle Formation (Lower Eifelian), ‘Mur des douaniers’, Vireux-Molhain, north-
ern France.
Fig. 1. Thysanopeltella (Septimopeltis) magnispina (MAillieux 1938). – Plaster cast of articu-
lated specimen, NH641 52.282. – Dorsal view, x 2.2.
Figs 2-7. Cyphaspis n. sp. A
2. Internal mould of articulated specimen, NH641 52.283. – a) Dorsal view, x 2.7;
b) anterior view, x 3.7; c) lateral view, x 3.7.
3. Internal mould of articulated specimen, NH641 52.284. – a) Dorsal view, x 3.8;
b) lateral view, x 4.0.
4. Internal mould of articulated specimen with partially exfoliated cephalon of
Geesops sparsinodosus gallicus struve 1982, NH641 52.285. – Dorsal view, x 3.7.
5. Partially exfoliated cephalothorax, NH641 52.287. – a) Dorsal view, x 3.2; b) lateral
view, x 3.5; anterior view, x 2.9.
6. Internal mould of articulated specimen, NH641 52.286. – a) Lateral view, x 2.9;
b) dorsal view, x 2.4.
7. Internal mould of articulated specimen, NH641 52.288. – a) Lateral view, x 3.3;
b) dorsal view, x 3.8.
eschweizerbartxxx sng-
Senckenbergiana lethaea, 86 (1); 2006 Plate 3
A. P. vAn viersen: New Middle Devonian trilobites from Vireux-Molhain (Ardennes, northern France)
