On the “ Coccodus ” lindstroemi species complex (Pycnodontiformes, Gladiopycnodontidae) from the marine Late Cretaceous of Lebanon, with the description of two new genera
Author
Taverne, Louis
0CF81641-1DD1-4CBD-9735-F1FE7EB0BCF5
Royal Belgian Institute of Natural Sciences of Belgium, Directorate Earth and History of Life, Rue Vautier 29, B- 1000 Brussels, Belgium. E-mail: louis. taverne @ gmail. com & urn: lsid: zoobank. org: author: 0 CF 81641 - 1 DD 1 - 4 CBD- 9735 - F 1 FE 7 EB 0 BCF 5
Author
Capasso, Luigi
C79C14CF-C1D7-48E3-9BA9-CAD8AA0909F7
Museo Universitario dell’Universitá “ G. d’Annunzio ” di Chieti-Pescara, Piazza Trento e Trieste 1, I- 661000 Chieti, Italy. E-mail: lcapasso @ unich. it & urn: lsid: zoobank. org: author: C 79 C 14 CF-C 1 D 7 - 48 E 3 - 9 BA 9 - CAD 8 AA 0909 F 7
text
European Journal of Taxonomy
2014
2014-11-05
101
1
27
journal article
21945
10.5852/ejt.2014.101
3216f841-dd7a-4f3e-bf08-fee6aa61d454
2118-9773
3838770
C320F2F8-E9BB-46FC-9A0C-56ECF4B1CE2B
Joinvillichthys kriweti
sp. nov.
urn:lsid:zoobank.org:act:
B8C4822F-44CA-4776-8455-452C5DBDCA1C
Figs 12-16
Diagnosis
Joinvillichthys
with a body depth equal to 46.0 % of the standard length. A dorsal prominence present on the frontal. Maxilla elongated. Large parietal. Dermosupraoccipital sutured to the parietal and not to the dermopterotic. Dermopterotic much longer than deep. Small dermosphenotic. Comma-shaped opercle. Anterior ventral branch of the cleithrum lost. Broad and short pectoral spine articulated on the ventral margin of the cleithral posterior process. Caudal fin double emarginated.
Etymology
The name of the new species is dedicated to Dr Jürgen Kriwet (Vienna) who has greatly improved our knowledge of the pycnodontiform fishes.
Holotype
LEBANON
:
sample CLC S-137
, a complete specimen from Haqel (
Fig. 12
), total length:
91 mm
.
Paratype
LEBANON
: sample
AMNH
4517a (3698) and counterpart, an incomplete specimen from Hgula (
Hay 1903
: pl. 29,
fig. 1
); only the head and the beginning of the body are preserved, length:
63 mm
.
Formation and locality
Marine Upper Cenomanian, Haqel and Hgula,
Lebanon
.
Morphometric data
(
Fig. 13
)
The morphometric data are given in % of the
holotype
standard length (
76 mm
)
Length of the head (dermosupraoccipital included) …………………………………………… 54.2 % Length of the cephalo-thorax (cleithrum included) ………………………………………… 75.3 % Depth of the head (without the nuchal horn) ……………………………………………… 43.8 % Length of the nuchal horn …………………………………………………………………… 27.7 % Maximum depth of the body (just behind the nuchal horn) ………………………………… 46.0 % Predorsal length ………………………………………………………………………………… 76.6 % Basal length of the dorsal fin …………………………………………………………………… 9.8 % Preanal length …………………………………………………………………………………… 80.4 % Basal length of the anal fin ………………………………………………………………………… 6.4 % Depth of the caudal peduncle ……………………………………………………………………… 9.8 %
Fig. 12.
Joinvillichthys kriweti
gen. et sp. nov.
Holotype, CLC S-137.
Osteology
1. The skull
(
Fig. 14
)
The general morphology of the skull is rather close to that of
Joinvillichthys lindstroemi
and the cranial dermal bones also are ornamented with small tubercles. However, there are many small differences in the head skeleton of the two fishes. Thus the description that follows will principally emphasize these differences.
The skull is shorter and deeper than in
Joinvillichthys lindstroemi
. Its depth, from the upper margin of the dermosupraoccipital to the lower margin of the cleithrum, is equal to 83 to 86 % of its length, from the tip of the snout to the basis of the nuchal horn.
The rostrum lengthening is less pronounced. The prefrontal is broader and has a very sinuous suture with the frontal. Its anterior tip also bears very small spines but is less outpacing of the lower jaw level. The frontal is broader but does not outpace posteriorly the level of the orbit. The bone bears a small dorsal prominence. The dermosupraoccipital is longer and is sutured to the parietal and the supratemporal but not with the dermopterotic. The parietal is considerably larger. The dermopterotic is longer but much thinner. The supratemporal is sutured to the parietal and reaches the dermopterotic at only one point. As in
Joinvillichthys lindstroemi
, the long nuchal horn is supported only by the dermosupraoccipital.
Fig.
13.
Joinvillichthys kriweti
gen. et sp. nov.
General reconstruction based on
holotype
, CLC S-137.
The orbitosphenoid and the pleurosphenoid are present in the orbit, just below the frontal, but the basisphenoid is not visible.
The toothless premaxilla is longer and narrower. The toothless maxilla also is narrower and more elongate. The lower jaw is composed with the same bones but is longer. The dentary bears two small incisiform teeth and its ventral margin is denticulated. The articulation with the quadrate is located at the level of the posterior border of the orbit.
A fragment of a large first infraorbital is preserved on the suture between the prefrontal and the premaxilla. The sclerotic ring is visible in the orbit.
The hyomandibula and the preopercle are sutured together. The exposed part of the hyomandibuladermohyomandibula is larger than in
Joinvillichthys lindstroemi
but still much smaller than the considerably enlarged preopercle. The opercle is broader and comma-shaped, with the sharp end dorsally located. A part of the anterior ceratohyal and two small branchiostegal rays are visible behind the lower jaw.
Fig. 14.
Joinvillichthys kriweti
gen. et sp. nov.
Reconstruction of the skull and the pectoral girdle based on holotype, CLC S-137.
2. The girdles
(
Figs 14
,
16
)
The bones of the gigantic pectoral girdle have the same size and shape as in
Joinvillichthys lindstroemi
. However, two important differences exist. The anterior ventral branch of the cleithrum is lost. No postcleithrum is visible, but that is perhaps due to the fossilization. The pectoral spine is shorter, much broader and is not articulated with the rear of the cleithrum but more anteriorly on its lower margin.
A small pelvic girdle is present. Indeed, a part of a vertically oriented pelvic bone is visible under a broken part of the cleithrum.
3. The axial skeleton
(
Fig. 13
)
The trunk is fusiform but proportionally deeper than in
Joinvillichthys lindstroemi
. The axial skeleton is incomplete. Three vertebral segments are missing near the caudal peduncle. There are 16 neural spines (the three missing ones included) before the epichordal series. Only 8 haemal spines are preserved. The total number of haemal spines must be around 12 or 13. The neural and haemal spines are short but broad. The neural and haemal arches surround almost completely the notochord. No ribs are visible. The postcoelomic bone is well developed and backwardly oriented.
Fig. 15.
Joinvillichthys kriweti
gen. et sp. nov.
Caudal skeleton of holotype, CLC S-137. The arrows
indicate the positions of the most external dorsal and ventral procurrent rays of the caudal fin.
4. The dorsal and anal fins
(
Fig. 13
)
The short dorsal and anal fins are located at the mid-length of the body. There are 9 pterygiophores and 9 rays in the dorsal fin. The anal fin contains 7 rays, but the number of anal pterygiophores is not determinable. The first dorsal and anal ray is spiny. The other rays are segmented.
5. The caudal skeleton
(
Fig. 15
)
The caudal skeleton of the
holotype
is partly preserved. There are 6 short and broad epichordals and 7 hypochordals. However, one or two anterior hypochordals are missing, so the complete series must be composed of 8 or 9 elements. The fifth preserved hypochordal is strongly enlarged. No urodermal is visible, but the region where theses bones are usually present is not preserved.
The caudal fin is double emarginated (
Poyato-Ariza & Wenz 2002
: fig. 36E) and contains 19 principal segmented caudal rays, the 2 external being pointed and the 17 others branched. There are 6 ventral and at least 4 dorsal procurrent rays.
Fig. 16.
Joinvillichthys kriweti
gen. et sp. nov.
Holotype, CLC S-137.
A
. Dorsal ridge scutes.
B
. Anterior flake-like body scales.
C
. Posterior scute-like body scale.
D
. Ventral keel scutes.
6. Squamation
(
Fig. 16
)
The squamation is the same as in
Joinvillichthys lindstroemi
. There are 7 spiny scutes in the dorsal ridge and at least 3 spiny scutes in the ventral keel. The two posterior ventral scutes are associated with the ventral margin of the postcoelomic bone. The body scales are slightly ornamented with tubercles. Anteriorly, they are small and flake-like. Posteriorly, there are much larger, irregular and scute-like shaped.