Content uploaded by Bernard Seret
Author content
All content in this area was uploaded by Bernard Seret on Jul 18, 2016
Content may be subject to copyright.
Accepted by M.R. de Carvalho: 25 May 2016; published: 15 Jul. 2016
ZOOTAXA
ISSN 1175-5326 (print edition)
ISSN
1175-5334
(online edition)
Copyright © 2016 Magnolia Press
Zootaxa 4138 (2): 291
–
308
http://www.mapress.com/j/zt/
Article
291
http://doi.org/10.11646/zootaxa.4138.2.4
http://zoobank.org/urn:lsid:zoobank.org:pub:FA636B00-03FE-43F2-BF15-2D00D06E33B4
Rhynchorhina mauritaniensis, a new genus and species of wedgefish from the
eastern central Atlantic (Elasmobranchii: Batoidea: Rhinidae)
BERNARD SÉRET
1,3
& GAVIN J.P. NAYLOR
2
1
IchtyoConsult, 6 bis rue du Centre, 91430 Igny, FRANCE. E-mail: seret.bernard@orange.fr
2
Hollings Marine Laboratory, 331 Fort Johnson Road, Charleston, SC 29412, USA. E-mail: gjpnaylor@gmail.com
3
Corresponding author
Abstract
A new wedgefish, Rhynchorhina mauritaniensis gen. et sp. nov., is described from three specimens collected in the shal-
low waters of the shoal “Banc d’Arguin”, off Mauritania (Eastern Central Atlantic). The new genus is mainly distin-
guished from its close relatives, members of the genus Rhynchobatus, by its snout shape, more broadly rounded like that
of the shark-ray Rhina ancylostoma, instead of being typically wedge-shaped as in Rhynchobatus species. The new species
resembles the common West African wedgefish, Rhynchobatus lubberti, in having a similar colour pattern, but differs in
snout shape. The new genus is supported as genetically distinct by comparative analysis of the mitochondrial NADH2
gene.
Key words: Rhinidae, Rhynchobatus mauritaniensis, new genus and species, false shark ray, eastern central Atlantic
Introduction
The genus Rhynchobatus Müller & Henle, 1837 comprises seven described species of moderate-sized to giant
(attaining between 0.8 and more than 3 m total length) shark-like batoids. Rhynchobatus species were placed in the
group Rhinae of the family Squatinorajae by Müller & Henle (1841), then variably placed in the family
Rhinobatidae (Norman, 1926; Compagno, 1986), Rhynchobatidae (Bigelow & Schroeder, 1953; McEachran et al.,
1996; Last & Stevens, 2009; Compagno & Last, 2008, 2010; Last et al., 2013; Naylor 2012) and Rhinidae
(Compagno & Last, 1999; Séret, 2016; Last et al., in press).
The genus Rhina Bloch & Schneider, 1801 has also been variably placed in the family Rhinobatidae (Norman,
1926), Rhynchobatidae (Bigelow & Schroeder 1953; Compagno, 1986) and Rhinidae (McEachran et al., 1996;
Compagno & Last, 1999; Last & Stevens, 2009; Naylor 2012, 2016; Last et al., in press). Anatomical characters
and molecular phylogenetic analyses favour its placement with Rhynchobatus in the family Rhinidae alongside the
new genus herein described, Rhynchorhina.
Rhinid species are called ‘wedgefishes’ because of their distinctive wedge-shaped snout, but are also called
giant guitarfishes and sharkfin guitarfishes. Wedgefishes are widespread and common in inshore tropical waters of
the Eastern Atlantic, Indian Ocean, and Western Pacific. In the Eastern Central Atlantic, only one species was
known, the West African Rhynchobatus lübberti Ehrenbaum, 1915, occurring in coastal waters from Mauritania to
Congo.
The “Banc d’Arguin”, region of Mauritania (Fig. 1) is a large sandy shoal, flooded by enriched waters of the
adjacent upwelling, which has promoted the development of a rich biodiversity and productive marine resources.
This unique habitat has been protected since 1976 when the National Park of Banc d’Arguin (PNBA) was
established. Only the native Imragen are allowed to fish inside the Park, using traditional and sustainable methods.
This fishery is managed by the Mauritania scientific institute IMROP (Institut Mauritanien de Recherche
Océanographique et des Pêches).
In 1998, fishery observers from this institute collected a strange wedgefish resembling the West African
SÉRET & NAYLOR
292
·
Zootaxa 4138 (2) © 2016 Magnolia Press
wedgefish Rhynchobatus lübberti, but with a rounded snout (Fig. 2A), instead of a wedge-shaped one. The skin of
the dorsal side of this specimen was removed, salted and dried (Fig. 2B), then sent to BS for identification. Despite
the poor state of the skin, the rounded snout was obvious and the occurrence of a new species was suspected.
Fishery observers were asked to pay special attention to wedgefishes in the landings, and on 14
th
February 2000, a
large male of 224 cm TL was collected near the Imragen village of Iwik. When the fishery observer noticed the
specimen, it had already been eviscerated and salted, and found lying on clays to be dried according to the local
method of preservation (“salted and dried”); the fins had been removed to be sold separately. One of the authors
(BS) was invited to Mauritania to examine this specimen. It was obvious that the two specimens collected were
from an undescribed wedgefish, as the rounded snout of the two available specimens, caught in different times,
were unlikely to be due to malformations or injury. In an effort to collect a specimen for a species description of the
new species, a reward was offered to collect a specimen to be kept whole and deep-frozen or on ice. On February 6,
2003, the staff of IMROP and PNBA collected a female of 204 cm TL. The specimen was landed and kept at Iwik.
Unfortunately, despite the instructions given in the reward advertisement, the fins had been removed on board.
Fortunately a fishery observer was able to trace the fate of the removed fins and found them in a local shark fin
dealer. Four additional specimens have been observed by fishery observers between 1998 and 2012, but none were
preserved.
This strange wedgefish with a rounded snout represents a new genus and a new species that are described
herein based on the three preserved specimens.
FIGURE 1. Map showing the National Park of Banc d’Arguin (PNBA) off Mauritania (northwestern Africa) with the two
localities where the specimens of Rhynchorhina mauritaniensis sp. nov. were collected: Iwik and R’Guieba (from Google
Earth).
Zootaxa 4138 (2) © 2016 Magnolia Press
·
293
NEW GENUS AND SPECIES OF WEDGEFISH
Material and methods
Morphometric methodology follows those developed by Bigelow & Schroeder (1953), Compagno (1984, for the
fins), Compagno & Randall (1987), Randall & Compagno (1995), and Last et al. (2004). Measurements were
expressed as percentages of total length (TL). To take the measurements of the fins that were removed when the
holotype was caught, they were attached with clips to the trunk in a position as natural as possible. Vertebral centra
and pectoral-fin radials have been counted from radiographs. The types are preserved in the collection of the
Muséum national d’Histoire naturelle, Paris (MNHN). The dried skin (MNHN 2003-611) was rehydrated and stuck
to a plywood board. The large salted and dried specimen (MNHN 2003-612) was rehydrated, then fixed in formalin
and maintained in a position as natural as possible. The third specimen (MNHN 2003-610) was fixed in formalin.
Molecular analysis used tissue samples from the dried specimen MNHN 2003-611. DNA was extracted
following methods described in Naylor et al. (2012), but yielded DNA that was severely degraded. PCR
amplification of several mitochondrial markers was attempted using primers optimized to target genes of closely
related species, but failed (repeatedly). Attempts were then made to obtain sequences using RNA target capture—a
system that is commonly used by the earlier DNA community to obtain DNA sequences from fossils with degraded
DNA. Briefly, pieces of RNA termed "baits" that have a high binding affinity are designed to match the sequences
of a closely related species. These RNA "baits" are then used to interrogate a genomic library derived from the
target specimen. If all goes well, the baits bind to the degraded target DNA which is amplified and subsequently
sequenced on a next generation sequencing platform (for protocol details, see Li et al. 2013). This approach
allowed us to retrieve the complete mitochondrial genome for the specimen. We restricted our analysis to the
NADH2 sequence as this was available for closely related taxa. DNA sequences were edited using Geneious® Pro
v. 6.1.7 (Biomatters Ltd Auckland, New Zealand). Edited sequences were translated to amino acids and aligned
with corresponding NADH2 sequences from representatives of closely related species of Rhynchobatus, Rhina and
several outgroup taxa. Aligned amino acid sequences were translated back, in frame, to their original nucleotide
sequences, to yield a nucleotide alignment. The full protein-coding alignment was 1044 nucleotides long. A
Neighbour Joining tree was estimated using Tamura Nei Distance using the software package Paup*4.0 version
a148.
Abbreviations: IMROP for “Institut Mauritanien de Recherche Océanographique et des Pêches”; PNBA for
“Parc National du Banc d’Arguin”, and FIBA for “Fondation Internationale du Banc d’Arguin”.
Rhynchorhina gen.nov.
Type species. Rhynchorhina mauritaniensis sp. nov. (new designation).
Diagnosis. The genus Rhynchorhina is distinguished from the closely related genus Rhynchobatus by its
distinctive rounded snout. Head length (dorsal) 12.5–13.7 % TL; head length (ventral) 21.0–23.2 % TL; preorbital
length 8.7–9.5 % TL; preoral length 10.2–10.9 % TL; prenasal length 8.4–9.1 % TL.
Etymology. A composite name derived from Rhynchobatus and Rhina to indicate that the new genus exhibits
features of both genera, having a Rhynchobatus-like body with a rounded snout resembling Rhina.
Rhynchorhina mauritaniensis sp. nov.
(Figs. 2–14, Table 1)
English name: False shark ray; French name: Raie-guitare mauritanienne; Hassaniya name: girhgette lemdaken
G. n., sp. n.: Séret, 2009 (abstract IPFC); Séret, 2016: 1355 (in key, fig. 2).
Holotype. MNHN 2003-610, female 2040 mm TL, Iwik, Banc d’Arguin, Mauritania, caught in a trammel net,
collected by IMROP fishery observers Amadou Sall, 6 February 2003. Dorsal and caudal fins, and spiral valve
preserved separately. Photographs of freshly caught and defrosted specimen available.
Paratypes. (2 specimens). MNHN 2003-612, adult male 2240 mm TL (estimated, as the caudal fin had been
cut, along with the dorsal fins), carcass eviscerated and dried, then rehydrated and fixed in formalin, without the
dorsal and caudal fins, caught in a trammel net, Iwik, Banc d’Arguin, Mauritania, collected by IMROP fishery
SÉRET & NAYLOR
294
·
Zootaxa 4138 (2) © 2016 Magnolia Press
observer Abdallahi, 14 February 2000; photograph of freshly caught specimen available. MNHN 2003-611, male
930 mm TL, a dried skin, R’Gueïba, Banc d’Arguin, Mauritania, caught in a trammel net (tollo), collected by
IMROP fishery observer Ely, 4 March 1998; photograph of freshly caught specimen available.
FIGURE 2. Rhynchorhina mauritaniensis sp. nov., paratype MNHN 2003-611, male ca. 930 mm TL. A: Old photograph from
IMROP showing the specimen freshly caught in 1998. B: The dried skin of the same specimen deposited in MNHN collection
and stuck on a plywood board (photo B.S.).
Diganosis. A large wedgefish (maximum TL 275 cm) with a heavy shark-like body, head somewhat flattened,
snout tip broadly rounded (holotype, and paratype MNHN 2002-611) to somewhat quadrangular (paratype MNHN
2003-612). Tail with a dermal fold along each lower edge. Two large and falcate dorsal fins; caudal fin with distinct
upper and lower lobes. Two conspicuous dermal folds on posterior margin of spiracles. Nostrils very large and
oblique, separated from each other and from the mouth; anterior nasal flap small (not extending to inner nostril
corner). Jaws moderately undulated; about 66/72 rows of oral teeth arranged in pavement. A row of pointed thorns
along each rostral ridge, two/three additional thorns may occur on snout tip, single row of thornlets and thorns in
front of orbit extending backward to level of spiracles; a median row of about 36 large, pointed thorns from nape to
first dorsal fin and six between dorsal fins, median thorns flanked by two other shorter rows on the nape-shoulder
area, additional short rows of thorns may be present on outer shoulders. Body covered with small dermal denticles,
their crowns with a median posterior cusp, an extension from the median ridge, and short lateral cusp. Dorsal side
greyish to greenish with numerous white ocelli-like spots; large black transverse blotch on ventral snout tip.
Description. Table 1 gives measurements expressed as proportions of total length. Very large ray with heavy
shark-like body; head somewhat flattened, snout tip broadly rounded, bell-shaped, or slightly quadrangular; trunk
thick, very wide at pectoral axil, then conical and tapering regularly rearward to caudal fin; tail rounded in cross
section dorsally and almost flat ventrally. Apices of pectoral and pelvic fins broadly angular. Tail length from
Zootaxa 4138 (2) © 2016 Magnolia Press
·
295
NEW GENUS AND SPECIES OF WEDGEFISH
anterior cloaca 1.6 times precloacal length, 2.7 times its width at pectoral-fin insertion and 11.3 times its width at
caudal-fin origin. Head rather short, its ventral length 21.0–23.2 % TL; snout short, its preoral length 10.2–10.9%
TL, 1.7–1.8 times mouth width, 2.8–2.9 times internasal space; preorbital length 1.6–1.7 times interspiracular
space, 1.7–1.8 interorbital space; interorbital space concave and broad; eyes moderately large, about as large as
spiracles; spiracles oval with two conspicuous folds on posterior margin, the inner fold slightly smaller than the
outer one.
TABLE 1. Morphometric measurements expressed as percentage of total length (TL) of the holotype of Rhynchorhina
mauritaniensis sp. nov., MNHN 2003-610, female 2040 mm TL, paratype MNHN 2003-612, male adult 2240 mm TL,
and of two specimens of Rhynchobatus lübberti from West Africa, MNHN 1992-208, male 790 mm TL, and MNHN
1992-209, male 805 mm TL.
Rhynchorhina mauritaniensis sp. nov. Rhynchobatus lübberti
MNHN
2003-0610
MNHN
2003-0612
MNHN
1992-0208
MNHN
1992-0209
Holotype Paratype Congo-Gabon Sénégal
female male adult male male
Measurement in % TL 2040 mm TL 2240 mm TL 790 mm TL 805 mm TL
Fork length 85.4 94.2 94.8
Disc width 36.8 37.3 39.7 39.5
Head length (dorsal) 12.5 13.7 22.7 21.7
Snout width at level of spiracle 18.1 18.6 20.2 19.5
Distance snout—D1 40.5 42.9 52.3 50.1
Distance snout—D2 57.9 60.3 70.0 68.2
Distance snout—caudal fin 71.1 73.5 86.0 84.3
D1 anterior margin length 10.8 13.2 13.8
D1 hight 11.2 9.3 11.8
D1 base length 5.7 5.7 5.0
D1 inner margin length 4.9 4.8 5.2
D1 posterior margin length 10.7 9.8 9.9
Distance D1 - D2 11.5 12.2 12.5
D2 anterior marginlength 10.8 12.0 12.0
D2 hight 9.8 9.5 9.9
D2 base length 4.9 4.9 5.1
D2 inner margin length 3.7 4.2 4.4
D2 posterior margin length 8.8 8.4 9.3
Caudal upper margin length 11.5 15.0 15.2
Caudal hight 13.4 12.5 13.8
Caudal lower lobe anterior margin length 8.9 10.1 10.8
Distance snout—pectoral apex 28.5 30.4 39.1 40.0
Distance snout—anterior margin of orbit 8.7 9.5 17.0 16.9
Distance snout—anterior margin of eye ball 9.3 10.1 17.7 17.5
Distance snout— anterior margin of spiracle 11.7 13.0 20.9 20.7
Distance snout—posterior margin of spiracle 12.8 13.9 22.3 22.5
Orbit length 2.8 3.4 4.7 3.9
Eye ball length 1.5 1.7 3.2 2.8
Spiracle hight 2.2 1.7 2.6 2.6
......continued on the next page
SÉRET & NAYLOR
296
·
Zootaxa 4138 (2) © 2016 Magnolia Press
Nostril very large, elongate, oblique with inner end forming an angle of about 120°; nostril outer corner close
to anterolateral margin of head; nostril length 1.2–1.3 longer than internasal space. Nostril anterior aperture slit-
like, length 4.9 times in nostril length; posterior aperture long and circumflex-shaped, with shorter inner part,
length 1.8 times in nostril length. Anterior nasal flap short-based, base length 3.2 times nostril length; with
moderately long finger-like outer lobe and a narrow and low inner lobe; only slightly overlapping nostril, and not
extending into internasal space. Posterolateral nasal flap narrow and extending about half-way along posterior
margin of nostril. Mouth almost straight with thick lips and grooves around its corners; mouth width 1.2–1.3 times
nostril length; jaws moderately undulated; teeth small, with blunt rhomboidal crowns, similar in both jaws, and
arranged in pavement in 66/72 rows. Gill slits s-shape, distance between first gill slits 1.2–1.4 times distance
between fifth gill slits.
TABLE 1. (Continued)
Rhynchorhina mauritaniensis sp. nov. Rhynchobatus lübberti
MNHN
2003-0610
MNHN
2003-0612
MNHN
1992-0208
MNHN
1992-0209
Holotype Paratype Congo-Gabon Sénégal
female male adult male male
Spiracle width 1.2 0.9 1.5 1.6
Interorbital space 4.9 5.3 5.4 5.3
Inter-eye space 6.6 7.2 7.1 7.0
Interspiracular space 5.2 5.6 6.1 6.1
Pectoral anterior margin length 12.1 15.4 17.2 16.9
Pectoral posterior margin length 15.9 15.4 15.0 16.9
Pectoral inner margin length 3.8 5.9 4.7
Pectoral - pelvic space 5.2 3.2 4.3
Pelvic anterior margin length 5.2 6.3 7.7 8.0
Pelvic posterior margin length 9.9 10.3 8.4 10.1
Pelvic total length 11.0 11.8 13.1 13.4
Distance snout—anterior margin of nostril 8.4 9.1 15.1 15.2
Distance snout—posterior margin of nostril 9.4 10.3 18.2 18.1
Distance snout—anterior margin of mouth 10.2 10.9 19.5 18.6
Distance snout—upper jaw (internal) 10.8 12.1 20.6 19.5
Internarial space (anterior) 10.6 11.7 12.0 12.2
Internarial space (posterior) 3.5 3.8 3.8 3.9
Nostril length 4.7 4.9 5.8 5.8
Mouth width (internal) 5.6 6.2 6.1 5.6
Distance nostril to snout anterior margin 1.6 1.6 1.8 1.7
Mouth width (external : with "lips) 6.7 7.5 7.6 6.8
1st gill slit length 1.6 1.7 2.0 1.9
5th gill slit length 1.0 1.4 1.3 1.3
Distance between 1st gill slits 14.3 15.2 15.4 15.4
Distance between 5th gill slits 11.5 11.7 11.3 11.5
Distance snout - anterior margin of cloaca 37.4 46.0 50.4
Head length (ventral) 21.0 23.2 32.2 31.9
Body width at pectoral axil 13.8 13.9 13.4
Tail width at caudal origin 3.3 3.2 3.6
Zootaxa 4138 (2) © 2016 Magnolia Press
·
297
NEW GENUS AND SPECIES OF WEDGEFISH
FIGURE 3. Rhynchorhina mauritaniensis sp. nov., paratype MNHN 2003-612, adult male 2240 mm TL. A: Specimen freshly
caught at Iwik on 14
th
Febrary 2000 (photo B. Valadou). B: Same specimen rehydrated and fixed in formalin, deposited in
MNHN collection (photo B.S.). C: Ventral view of freshly caught specimen (photo B. Valadou).
SÉRET & NAYLOR
298
·
Zootaxa 4138 (2) © 2016 Magnolia Press
FIGURE 4. Rhynchorhina mauritaniensis sp. nov., holotype MNHN 2003-610, female 2040 mm TL. A: Specimen freshly
caught at Iwik on 6
th
Febrary 2003 (Photo B. Valadou). B: Dorsal view of defrosted specimen (photo B.S.).
First dorsal fin tall and rather narrow, with an narrowly rounded apex; second dorsal fin triangular, shorter than
first dorsal fin, somewhat raked, and with a rather angular apex. Origin of first dorsal fin about at level of pelvic-fin
inner margin; dorsal fins widely separated, interdorsal space about 2 times first-dorsal base length; interspace
between second dorsal fin and origin of caudal-fin upper lobe about as long as interdorsal space. Upper lobe of
caudal fin elongated with a rather angular apex; lower lobe of caudal fin well developed, ogive-shaped. Skin
covered with small, close-set dermal denticles, with rounded crowns, posterior cups more or less marked off. Three
distinct thornlets at snout tip; irregular row of thornlets around orbits and above spiracles; a mediodorsal row of
about 36 thornlets from nape to first dorsal fin; a row of 6 thornlets between dorsal fins; a shorter row of 14–15
thornlets on each shoulder, oriented parallel to the mediodorsal row; 2–3 additional thornlets on above
scapulocoracoid.
From a radiograph (Fig. 14) the rostrum is wide, with thick rostral ridges, surrounding a wide ovoid fontanelle
(Fig. 14); the nasal capsules are oblique and elongated.
Zootaxa 4138 (2) © 2016 Magnolia Press
·
299
NEW GENUS AND SPECIES OF WEDGEFISH
FIGURE 5. Rhynchorhina mauritaniensis sp. nov. A: Ventral view of freshly caught MNHN 2003-610 (photo B. Valadou). B:
Ventral view of the same specimen after rehydration (photo B.S.).
Total vertebral centra (without the synarcual segments) 200–205, with 46–48 monospondylous centra and
154–157 diplospondylous centra. Total pectoral-fin radials 64, with 38 propterygials, 10 mesopterygials, and 26
metapterygials; several radials are fused at base. Spiral valve with 15 large and several small turns.
Colour. Dorsal side greyish to greenish brown, covered with very numerous ocelli-like spots with whitish
centres and rimmed by cloudy dark grey rings; spots more or less in regular rows on side of trunk; spots present on
pectoral and pelvic fins; no spots or very few on head; blackish markings on shoulders in the smallest specimen,
absent in large adult specimens. Thornlets around orbit and in dorsal rows with brownish tips. Ventral side white,
posterior margins of pectoral and pelvic fins greyish; a large transverse black blotch (in holotype) or cluster of dark
spots (in paratype) at snout tip.
Size. The largest preserved individual is the holotype MNHN 2003-612 (adult male 2240 mm TL). However, a
larger male of 275 cm (total length without the caudal fin) was observed in March 1998 at Agadir, by IMROP
fishery observer Kidé, but not collected.
SÉRET & NAYLOR
300
·
Zootaxa 4138 (2) © 2016 Magnolia Press
FIGURE 6 . Rhynchorhina mauritaniensis sp. nov. A: Dorsal view of head of holotype MNHN 2003-610. B: Dorsal view of
head of paratype MNHN 2003-612 (photos B. Valadou).
Zootaxa 4138 (2) © 2016 Magnolia Press
·
301
NEW GENUS AND SPECIES OF WEDGEFISH
FIGURE 7. Rhynchorhina mauritaniensis sp. nov., holotype MNHN 2003-610. A: Dorsal and caudal fins that were cut off by
a fisherman. B: Fins in place maintained with clips (photos B.S.).
Distribution. The new wedgefish Rhynchorhina mauritaniensis is only known from the shallow waters of
shoal “Banc d’Arguin”, Mauritania, off the following localities Agadir, Iwik, and R’Guieba (Fig. 1).
Biology. The female holotype had ripe ovocytes (Fig. 12), and remains of unidentified shrimps in its stomach;
the largest male (exceeding 275 cm TL) had five moray eels in its stomach, and weighted 44 kg (without fins).
Etymology. The new species is named after the Islamic Republic of Mauritania; the country where the only
known material has been collected.
Discussion
Although very rare, and so far endemic to the Banc d’Arguin National Park off Mauritania, this strange ray was
known to the native Imragen people who have a name in Hassaniya Arabic for this fish: girhgette lemdaken,
meaning guitarfish with rounded snout. Since the first available record (in 1998), six specimens have been reliably
recorded, but only three have been preserved (deposited in the MNHN fish collection), and only one preserved well
enough to enable the present description.
The new genus Rhynchorhina shares with the genus Rhina, its short and rounded snout, although not as evenly
rounded as in Rhina. However, it differs in many morphological features, such as having less undulated jaws than
in Rhina, and nostrils very distinct with the anterior nasal flap shorter (vs. extending to near the inner nostril corner
in Rhina).
SÉRET & NAYLOR
302
·
Zootaxa 4138 (2) © 2016 Magnolia Press
FIGURE 8. Rhynchorhina mauritaniensis sp. nov., holotype MNHN 2003-610. A: Head, ventral view. B: Right nostril. C:
Mouth (photos B.S.).
Zootaxa 4138 (2) © 2016 Magnolia Press
·
303
NEW GENUS AND SPECIES OF WEDGEFISH
FIGURE 9. Rhynchorhina mauritaniensis sp. nov., paratype MNHN 2003-612. A: Head, ventral view (photo B. Valadou). B:
Right nostril. C: Mouth (photos B.S.).
SÉRET & NAYLOR
304
·
Zootaxa 4138 (2) © 2016 Magnolia Press
FIGURE 10. Rhynchorhina mauritaniensis sp. nov., holotype MNHN 2003-610, dorsal view of snout showing three small
thorns at tip (photo B.S.).
FIGURE 11. Rhynchorhina mauritaniensis sp. nov., holotype MNHN 2003-610, spiral valve (photo B.S.).
FIGURE 12. Rhynchorhina mauritaniensis sp. nov., holotype MNHN 2003-610, ovary with ripe ovocytes (photo B.S.).
Zootaxa 4138 (2) © 2016 Magnolia Press
·
305
NEW GENUS AND SPECIES OF WEDGEFISH
FIGURE 13. Rhynchorhina mauritaniensis sp. nov. (drawing by J.F. Dejouannet).
FIGURE 14. Radiograph of the head of Rhynchorhina mauritaniensis MNHN 2003-610.
SÉRET & NAYLOR
306
·
Zootaxa 4138 (2) © 2016 Magnolia Press
FIGURE 15. Tree of NADH2 distance analysis (see Material and methods for details)
.
The new genus Rhynchorhina shares with the genus Rhynchobatus many morphological features, e.g.
morphology of its jaws and nostrils, but the snout is much shorter and rounded (vs. longer and wedge-shaped in
Rhynchobatus species).
Rhina and Rhynchobatus species are very morphologically different shark-like rays, and have often been
placed in different families (see Introduction), however some authors have placed them together in the same family
based on their shared morphological characters. Recent molecular analysis (Naylor et al., 2012; in press)
corroborates this view, indicating that Rhina is the sister group of Rhynchobatus, and the present analysis shows
that Rhina is the sister group of Rhynchobatus + Rhynchorhina, with the latter clearly distinct genetically from
Rhynchobatus (Fig. 15).
Beside the shape of the snout, R. mauritaniensis can be further distinguished from R. lübberti by the following
characters: smaller eye-ball, its diameter 1.5–1.7 % TL vs. 2.8–3.2 % TL, respectively; pelvic-fin length 11.0–11.8
% TL vs. 13.1–13.4 % TL; pelvic-fin anterior margin length, 5.2–6.3 vs. 7.7–8.0 % TL; nostril length, 4.7–4.9 %
TL vs. 5.8 % TL.
The Banc d’Arguin is a vast marine region of about 20 km long and covering 12,000 km
2
, with a rich variety of
habitats: the western side is under the influence of the open ocean with strong seasonal upwellings, and the centre
is a complex network of sandy and mud-flats and seagrass shoals, with numerous channels and basins. In some
near shore habitats, under the influence of a hot climate from the nearby Sahara desert, the environmental
conditions are extreme with a high sea temperature (39°C) and salinity (up to 80 g/l). The region is a former estuary
dating from the Pleistocene; the remaining river is a deep canyon that cuts the continental slope on the western side
of the Banc. These various habitats constitute refuges, nursery and feeding grounds for numerous fish species.
Relic populations have possibly survived and even developed in the Banc, such as some freshwater tilapias (Family
Cichlidae) whose populations are growing (Séverin-Reyssac & Richer de Forges, 1985). The strange Mauritanian
wedgefish represents a very endemic species.
Zootaxa 4138 (2) © 2016 Magnolia Press
·
307
NEW GENUS AND SPECIES OF WEDGEFISH
Comparative material
Rhynchobatus lübberti. MNHN 1969-274, female, Gulf of Guinea; MNHN 1982-002, male, Senegal; MNHN
1992-208, male 790 mm TL, Congo-Gabon; MNHN 1992-209, male 805 mm TL, Senegal; MNHN 1992-210,
female 1080 mm TL, Senegal; BMNH 1914.11.2.2 (type of R. atlanticus), female 754 mm TL, Nigeria.
Rhina ancylostoma. MNHN A-7658, juvenile, India; BMNH 1884.2.26.53, male juvenile, China; BMNH
1925.7.20.61.66-67, 2 embryos; 1850.6.22.1, jaws, China; BMNH 1909.7.12.6 jaws, India.
Acknowledgements
We thank the following persons who collected the specimens and provided information and photos on this rare
wedgefish: Matthieu Ducrocq (FIBA), Bénedicte Valadou (PNBA), Amadou Sall, Abdelkader Ould Mohamed
Saleck, Mohamed M’Bareck Ould Soueïlim (IMROP), Philippe Tous (French cooperation), along with Jean-
François Dejouannet (IRD) who rendered the drawing (Fig. 4), Franz Julien (MNHN) who restored the dried
specimen, Karl Daubet (Interpal) who kindly shipped the specimens from Mauritania to Paris. P. Last (CSIRO
Hobart) kindly provided comments and corrections.
References
Bigelow, H.B. & Schroeder, W.C. (1953) Fishes of the western North Atlantic. Part two. Sawfishes, guitarfishes, skates and
rays. Memoirs of the Sears Foundation of Marine Research, 1, 1–514.
Bloch, M.E. & Schneider, J.G. (1801) M.E. Blochii, Systema Ichthyologiae iconibus cx illustratum. Post obitum auctoris opus
inchoatum absolvit, correxit, interpolavit Jo. Gottlob Schneider, Saxo. Berolini. Sumtibus Auctoris Impressum et
Bibliopolio Sanderiano Commissum. Systema Ichthyologe, 584 pp.
Compagno, L.J.V. (1984) FAO Species Catalogue. Sharks of the World. An annotated and illustrated catalogue of shark species
known to date. FAO Fisheries Synopsis No. 125, 4, part 1 (Hexanchiformes to Lamniformes), 1–250; part 2
(Carcharhiniformes), pp. 251–655.
Compagno, L.J.V. & Randall, J.E. (1987) Rhinobatos punctifer, a new species of guitarfish (Rhinobatiformes: Rhinobatidae)
from the Red Sea, with notes on the Red Sea batoid fauna. Proceedings of the California Academy of Sciences, Series 4
(44), 335–342.
Compagno, L.J.V. (1986) Family no. 27: Rhinobatidae. In: Smith, M.M. & Heemstra, P.C. (Eds.), Smiths’ Sea Fishes. Struik
Publishers, Cape Town, pp. 128–131.
Compagno, L.J.V. & Last, P.R. (1999) Rhinidae, Wedgefishes. In: Carpenter, K.E. & Nem, V.H. (Eds.), FAO species
Identification Guide for Fishery Purposes. The living marine resources of the Western Central Pacific. Volume 3. Batoid
fishes, chimaeras and bony fishes part 1 (Elopidae to Linophrynidae). FAO, Rome, pp. 1418–1422.
Compagno, L.J.V. & Last, P.R. (2008) A new species of wedgefish, Rhynchobatus palpebratus sp. nov. (Rhynchobatoide:
Rhynchobatidae), from the Indo–West Pacific. In: Last, P.R., White, W.T. & Pogonoski, J.J. (Eds.), Descriptions of New
Australian Chondrichthyans. CSIRO Marine and Atmospheric Research Paper, 22, 227–240.
Compagno, L.J.V. & Last, P.R. (2010) A new species ofwedgefish, Rhynchobatus springeri (Rhynchobatoidei,
Rhynchobatidae), from the Western Pacific. In: Last, P.R., White, W.T. & Pogonoski, J.J. (Eds.), Descriptions of New
Sharks and Rays from Borneo. CSIRO Marine and Atmospheric Research Paper, 32, 77–88.
Compagno, L.J.V. & Randall, J.E. (1987) Rhinobatos punctifer, a new species of guitarfish (Rhinobatiformes:
Rhinobatidae)from the Red Sea, with notes on the Red Sea batoid fauna. Proceedings of the California Academy of
Sciences, Series 4 (44), 335–342.
Ehrenbaum, E. (1914) Ueber Fische von Westafrica, besonders von Kamerun. Der Fischerbote 6 (11–12), 401–409.
Hubbs, C.L. & Ishyama, R. (1968) Methods for the taxonomic studies and description of skates (Rajdae). Copeia, 1968, 483–
491.
http://dx.doi.org/10.2307/1442016
Last P.R., Compagno, L.J.V. & Nakaya, K. (2004) Rhinobatos nudidorsalis, a new species of shovelnose ray (Batoidea:
Rhinobatidae) from the Mascarene Ridge, central Indian Ocean. Ichthyological Research, 5, 153–158.
http://dx.doi.org/10.1007/s10228-004-0211-0
Last, P.R., Compagno, L.J.V., White, W.T. & Séret, B. (in press) Wedgefishes. In: Last, P.R. (Eds.), Rays of the World. CSIRO
Publishing, Melbourne, pp. 8–19.
Last, P.R. & Stevens, J.D. (2009) Sharks and Rays of Australia. 2nd ed. CSIRO Publishing, Melbourne, 644 pp.
Last, P.R., Ho, H.-C. & Chen, R.R. (2013) A new species of wedgefish, Rhynchonatus immaculatus (Chondrichthyes,
Rhynchobtidea), from Taiwan. Zootaxa, 3752 (1), 185–198.
SÉRET & NAYLOR
308
·
Zootaxa 4138 (2) © 2016 Magnolia Press
http://dx.doi.org/10.11646/zootaxa.3752.1.11
Li, C., Hofreiter, M., Straube, N., Corrigan, S. & Naylor, G.J.P. (2103) Capturing protein-coding genes across highly divergent
species. BioTechniques 54 (6), 321–326.
McEachran, J.D., Dunn, K.A. & Miyake, T. (1996) Interrelationships of the batoid fishes (Chondrichthyes: Batodea). In:
Stassny, M.L.J, Parenti, L.R. & Johnson G.D. (Eds.), Interrelatioships of Fishes. Academic Press, New York, pp. 63–84.
Müller, J. & Henle, F.G.J. (1837) Gattungen der Haifische und Rochen nach einer von ihm mit Hrn. Henle unternommenen
gemeinschaftlichen Arbeit über die Naturgeschichte der Knorpelfische. Bercht Akademe der Wssenschaften zu Berlin,
1837, 111–118.
Müller, J. & Henle, F.G.J. (1841) Systematische Beschreibung der Plagiostomen. Berlin, pp. 103–200.
http://dx.doi.org/10.5962/bhl.title.6906
Naylor, G.J.P. (2016) Chondrichthyan Tree of Life. Available from: https://sharksrays.org/ (Accessed 14 Jul. 2016)
Naylor, G.J.P., Caira, J.N., Jensen, K., Rosana, K.A.M., Straube, N. & Lakne, C. (2012) Elasmobranch phylogeny: a
mitochondrial estimate based on 595 species. In: Carrier, J.C., Musick, J.A. & Heithaus, M.R. (Eds.), Biology of sharks
and their relatives, Second Edition, pp. 32–56.
http://dx.doi.org/10.1201/b11867-4
Naylor, G.J.P., Yang, L., Corrigan, S. & de Carvalho, M.R. (in press) Phylogeny and classification of rays. In: Last, P.R. (Eds.),
Rays of the World. CSIRO Publishing, Melbourne.
Norman, J.R. (1926) A synopsis of the rays of the family Rhinobatidae, with a revision of the genus Rhinobatus. Proceedings
Zoological Society London, 941–982.
http://dx.doi.org/10.1111/j.1096-3642.1926.tb02228.x
Randall, J.E. & Compagno, L.J.V. (1995) A review of the guitarfishes of the genus Rhinobatos (Rajiformes: Rhinobatidae)
from Oman, with description of a new species. The Raffles Bulletin of Zoology, 43, 289–298.
Séverin-Reyssac, J. & Richer de Forges, B. (1985) Particularités de la faune ichtyologique dans un milieu sursalé du parc
national du Banc d’Arguin (Mauritanie). Océanographie Tropicale, 20 (1), 85–90.
Séret, B. (2009) A new genus and species of guitarfish from West Africa. Book of abstracts of the 8
th
Indo-Pacific Fish
Conference, Freemantle, 31
st
May–5
th
June 2009.
Séret, B. (2016) Rhinidae. In: Carpenter, K. (Ed.), FAO species identification guide for fishery purpose. The living marine
resources of the Eastern Central Atlantic. Volume 2, 1353–1357. FAO, Rome.
