SEASHELL COLLECTORS | Senegal Cone Shells

Senegal Cone Shells

Senegal Cone Shells (2001)
By Le Béon Roger

A. The Environment
B. The Landscapes
C. The Cone shells
D. ICONOGRAPHY & DISCUSSION
E. Comments

This article shows cones I have founded during a two years stay in Senegal (1990-1992). It is a tentative to illustrate as accurately as possible these species and to show the associate biota’s. For identification it use the help of the " Les cônes du Sénégal " publication by Marcel PIN and K.D. LEUNG TACK, publicised as a supplement of La Conchiglia n° 277, in 1995.

This document is the latest about this subject and even if the identification process of identification used is not widely accepted, mainly by the scientific old, it is still the most interesting publication concerning Senegal’s cones.. The other popular existing publication about cones shells, the " Cone shells " of Walls, is quite erroneous concerning the Senegal’s cones, as Marcel PIN says.

A. The Environment
Atlantic ocean waters of Senegal not allows an easy seashells collect by free diving as I have done as well as beach comber fishing during low tide. The sea , warm during summer is quite cold during winter. The visibility is usually poor on the sea side, and very often, the sea state is very hard with big waves due to the strong south west Alize wind, during a long period of the year. Only the rocky area of the Cap Vert peninsula allows such kind of collect during some quiet periods. These areas are mainly situated at the north and west of Dakar city. They are : The Yoff area, north of the peninsula with numerous rocks that's appears at low tide. The N’Gor area, where close to rocks piles, is a little sandy beach protected by the N’Gor island. The Almadies cape with rocks piles and two little beaches . The Ouakam area with high cliffs at the base of the higher Senegal’s hill " less Mamelles ", where some wide natural pools remains at low tide. The Fann area between Ouakam and Soumbedioun villages severely polluted an hardly beat by the waves. All long the corniche where are numerous little sandy bays with rocks piles and natural pools . This area is also quite polluted despite some hotels have their private beach here. Goree island situated close off the Dakar port. Here is a little beach surrounded by rocky areas and some high cliff. It is probably the best spot for shelling but the pollution is coming and some times the visibility is very poor. The Bel Air cape is edged by two beaches , the public " voile d’or " is a popular beach but totally sterilised, and the private military beach with a long pier and some rocky places. In all this area I never find any shell except beach ones. Southerly starts a large area which lays from the Hann bay to the Sine Saloum river mouth and then the very far Casamance province. On this " petite côte " some little villages like Popomguine, N’Gaparu, M’Bour and Joal Fadiouth allows to reach the sea side. Totally polluted between Hann and the cap des Biches this area only allows shelling at low tide and exceptionally by snorkelling with a very low visibility reduced to less than 20 centimetres Southerly the area is very rich (marginellas, helmets, volutes, murex, cones and even cypreae…), but the only means to catch them is by using trawlers or diving off shore on the rocky banks. Fishermen find very often interesting species that you can buy.

Goree island one of the best diving spot of Senegal. Just here bellow, is the Tacoma wreck ( between 15 and 20 meters) where is a very popular diving place used by the Dakar diving club.

B. The Landscapes


Goree island. The old prison, now a museum. Here behind this place is a submarine rock masswhere you can find if you are lucky some beautiful sanguinolenta endemic or the cone unifasciatus that is described lower.	In the far the Madeleines islands you can see from the Fann ClaudeL district. The island is a zoological reserve and the access is normally restricted. In the foreground you can find some C. unifasciatus but in very bad condition because the sea is often rough here.

Typical landscape of the petite côte with black rocks appearing at low tide and protecting the beach of the strong waves. Here in the N’Gaparou surroundings, you can find at some periods of the year, numerous C. cacao around the rocks. Free diving is difficult close to the sea side because the visibility is very poor. You might have the luck to find some beautiful Cyp. stercoraria very often greenish or sometimes very black	Typical landscape of the petite côte with black rocks appearing at low tide and protecting the beach of the strong waves. Here in the N’Gaparou surroundings, you can find at some periods of the year, numerous C. cacao around the rocks. Free diving is difficult close to the sea side because the visibility is very poor. You might have the luck to find some beautiful Cyp. stercoraria very often greenish or sometimes very black

C. The Cone shells

In his study M. Pin described eighteen species of Senegal’s cones. I only found thirteen of them. That are absent of my inventory are :

C. brugieresi (Kiener, 1945)

C. belairensis (Pin-Leung Tack, 1989)

C. mediterraneus (Hwass in Bruguière, 1792)

That do not, naturally, means that they do not exist. My investigations were probably outside their normal biotops. I’ve never investigated the Yoff area that is the normal breading zone of C. bruguieresis and C. mediterraneus as M. Pin says. On the other hand the Bel Air area becomes a real malacological desert. The only cone I found there was a big C. pulcher. The C.belairensis is disappeared .

The species I discovered are :

Species

Author

max. Size (mm)

Areas & means of collect

Sympatry

As M.Pin

my collect

hybridus
(lamarkii f. hybridus ?)

Kiener, 1845

51.5

From Almadies to Ouakam

tabidus
equinophilus
mercator
ermineus
pulcher

guinaicus

Hwass in Bruguière, 1792

Petite côte
By fisherman

cacao
pulcher
ambiguus
ermineus

equinophilus

Petuch,1975

Almadies' point

Id. hybridus

mercator

Linne, 1758

39.5

Almadies to Ouakam

Id. hybridus

cacao

Ferrario, 1983

55+

Petite côte

cacao
pulcher
ambiguus

cloveri

Walls, 1978

30.5

Région Ouakam

ermineus
hybridus

unifasciatus

(nota)

Kiener, 1845

40	47.3 (nota)

South Ouakam
to Gorée

hybridus
equinophilus
ermineus
pulcher
genuanus

genuanus

Linne, 1758

70+

Gorée
By fisherman (>20m)

Id unifasciatus

ambiguus

Reeve, 1844

By fisherman

Id guineicus

tabidus

Reeve, 1844

40-

Almadies to Gorée

hybridus
equinophilus
ermineus
pulcher
genuanus

ermineus

Born, 1778

70+

N’gor

Ouakam. Gorée

By fishermen Petite côte

hybridus
equinophilus
ermineus
pulcher
genuanus
cacao
ambiguus
cloveri
mercator

pinaui

Pin,1989

By diver Gorée area

Id. unifasciatus

pulcher

Lightfoot, 1786

200+

134

Everywhere

All species

D. ICONOGRAPHY & DISCUSSION

Conus hybridus (lamarkii hybridus ?)

This cone is quite common in the north and west part of the Cap Vert peninsula where it is less numerous than c.tabidus and c. mercator. At low depth you can find it by free diving . I discovered a special one near 12 meters deep at the foot of the Ouakam cliffs. It is special by its elongate form and its special drawing (but is it an hybridus ?) . I have found some species bigger than 50 mm, maximum length as Pin says.

*Typical form of C. hybridus* L : 51.5mm I : 25.8mm**	L : 44.7mm I : 21.2mm
Almadies (-1.5 metres)	Ouakam (-12 metres).

Three beautiful specimen of c. hybridus. >From left to right :

L : 51.5 . l : 25.8
L : 50.4 . l : 24.1
L : 51.4 . l : 25.7

Drawing are very variable. It may be all blue grey

with always present two clear bands at the lower third and at the shoulders level on the back.

Conus guinaicus

I only find two beached species on the " petite côte ". That is true, I never investigate the Popomguine area which is its birthing area as M.Pin says. I nevertheless received few specimens from local fishermen. It is quite easy to make the difference with C. hybridus because it is more thicker with a lower spire and a more regular drawing, the two white bands are absent or quite obsolete.

Beautiful specimen L: 53mm , l : 29mm

L : 46mm I : 27mm

Conus mercator

This kind small shell is present all long the north and west coast of the Cap vert peninsula. Very easy to find it lives in very little deep water. I never find it south of the N’Gor area while Pin says it was present nee Dakar city . It may be that is the result of the invading pollution ? It is easily recognisable despite a very varying drawing.

Typical form. L : 39.2 mm , l :22.2 mm.
Sector de N’Gor (-0.5 metres).

Two beautiful species . d= 39 and 38 mm


Different drawings. The juveniles have often very special drawings that become more classic when they become older.

Conus cacao

This cone which have been sometimes confused with C. mercator in the past is obviously very different with a general light brown pattern colour, more heavy, and presence of two clear bands at the first third and on the shoulders levels, even if the netting drawing and its general shape looks like this one. It is usually found on the petite côte area near N’Gaparou where the C mercator is absent. It is numerous at some period of the year (breeding time ?) half buried in the sand, close to the rocks.

Large specimen L : 45.1 mm , l : 258

Series with different patterns, but not as various as on c. mercator

Conus cloveri

I have find this species at only one place, at the foot of the Ouakam cliff in a large natural pool at low tide. In this very restricted area there were numerous pieces to gather with some big C. ermineus in very bad state. This little cone is quite easily recognisable and cannot be confuse with any other cone. It can be considered as quite rare. Very nice species in GEM condition are very rare.

Typical C. cloveri L : 30.5 mm, l : 16.4 mm.
Ouakam (-0.5 metres).

Serial. The drawing is quite constant but may obsolete on some specimens

Conus unifasciatus

I have some trouble identifying this species. Those I collected are quite typical of the description by M.Pin. However the places where I found them are quite different . Pin says they are from the northern area of the peninsula, but mine comes from and area spread from the Ouakam village and Goree island where they do not inhabit with the other species that Pin says. On an other hand their maximum length exceeds largely the 40 mm that Pin quotes.( 47 and 48 for the biggest).

I have found a colony quite homogeneous both by its black brown colour an its light weight aspect in regard to the other, in a very narrow area in Goree island.

In fact it seems to me, that apart its colour and for some specimens its more thick appearance, this species looks like closely to C. hybridus : same shape and density, same length range, and presence of two white bands… ?

C.unifasciatus Fann area,( -0.5 metres).
L : 47.1 mm , l : 25 mm . White bands quite obsolete

C . unifasciatus from Gorée ,( -1.5 metres).
L : 48.3 mm , l : 27 mm. White bands more visible with some white spots at the bands level.


*Serial of C. unifasciatus* from Goree. The white spots are more numerous on the small specimens.**	*Serial of C. unifasciatus from the Ouakam/ Fann area. Some specimens are grey and finely reticulated.*

Conus genuanus

Here is a very beautiful cone with no identification problem. Its shape and drawing are very constant. I only found one by diving at about 6 meters on a sandy bottom in Goree island. This is quite normal because it is usually found deeper. My other specimens come from fishermen on the " petite côte ".

C. genuanus, dredged in Hann bay . L :57.6 mm . l : 35.5 mm .

Serial. Constant drawing.

Conus ambiguus

I did not found this species by myself. The specimen I have come from fishermen of the " petite côte " area. There are two forms. The small one have a smooth shell lightly coloured of pink brown. The big form has a white background with some brown longitudinal flames. On the two forms there are brown radial markings on the shoulders.

Big form specimen dredged
. L : 66 mm l : 35.5 mm.

Small form specimen dredged.
L : 36.2 mm,L : 20 mm

Conus tabidus

This small cone is quite common at small depth on all the Dakar peninsula except its southern part. It lives often with C. mercator and C. hybridus. Small sized it is covered with a quite thick brownish periostractum ; There not any identification problem apart with the small specimen of C. ambiguus.

		C. tabidus have rounded shoulders. The brown flames drawings are less numerous on the spire area.
c. tabidus. L : 31.8 mm, l : 17.4 mm. Pointe des Almadies (0.5 meters)	**c. ambiguus might be confuse with C. tabidus**

Conus ermineus

This beautiful cone is present on all the Cap Vert peninsula area and in the islands so called where I had the opportunity to go and dive. Its birthing area is probably wider and transatlantic. C. ermineus () is also present in the Caribian area. It has a wide range of length, colour and drawings ; Its biotop is also very variable. You can found it in very few depth waters at low tide as well as at depth closing 20 to 30 meters (off the petite côte). However its shape is always the same and it can be identified easily.

Beautiful specimen dredged in the petite côte area. L : 71.8 mm , l : 38.6 mm.

Low depth specimen from the N’Gor area
L : 62.3 mm , l : 37 mm .

Specimens without drawing, yellow pattern ; dredged off petite côte. L : 52.7 mm , l : 29 mm.

Two species from Sal island ( Cabo Verde islands ). normal colour: 46 X 25.8 . red colour :
46 X 25.7

Conus pinaui

Recently described by Marcel Pin, it was named in honour of doctor Pinau, M. Pin’s friend, french radiologist from Dakar and great shells collector. They are both died recently. I had the opportunity to receive some rare species of this fine cone from the Dakar diving club director. Unfortunately only one remains in my collection, this explains the poor iconography. Collected by scuba diving off Goree at 20 meters, it is exactly identical to the M.Pin description. It do not looks like strictly to any other cone except, may be, to a C. ambiguus (the small form), witch had lost the drawings.

C. pinaui from the Hann bay ( 15 to 20 metres).
L : 34.7 mm ; l : 20.4 mm. Typical form

C. pinaui and C. ambiguus side by side. Questioning ?

Conus pulcher

Probably the world biggest cone , C. pulcher is present every where in Senegal, where it do not reach the huge size that you can find southerly in the west Africa area. Juveniles specimens are more attractive because of their more brighter colours and drawings. The specimens I have collected by free diving between 0.5 and 12 meters in the Cap Vert area, are broader and heavier than the dredged specimens.

C. pulcher typical from the Cap Vert peninsula, broad and heavy. Collected at Bel Air, outside the pier. L : 133 mm . l : 92 mm

C. pulcher dredged off the petite côte, Narrow and lighter.
L : 116 mm. L : 69 mm

Conus equinophylus

This cone is illustrated here but I had some difficulties due to its very short size to take pictures. I have found 4 specimens of this tiny cone at the pointe des Almadies area, in little depth water. The shells are strictly identical to the description of M. Pin.

E. COMMENTS

These comments are strictly personal . They only give my feeling without any scientific evidence since I do not have this competence. This will only show how difficult the Senegal’s cones identification is. These shells need to be more accurately studied

C. mediterraneus : I had the opportunity to see some specimens of this cone from the Alexandria area (Egypt), which resemble closely to the C. hybridus illustrated here. In an other hand the C. mediterraneus illustrated in the Pin’s study do not give any distinctive clues to make the difference with C. hybridus .

C. unifasciatus : like I explained before, numerous common characteristics exist with C.hybridus : general shape, size, two white stripes…

C. cacao : if you can easily distinguish this species from C. mercator, you can also find numerous common clues with C. hybridus : size, general shape,but a little broader, and presence of two white bands…

Considering that these cones are not living in the same places together, and that they are spread from north to south of the peninsula as follows : C. hybridus, C. unifasciatus, C. cacao, we are allowed to ask the question if it is not the same cone (why not C. mediterraneus ?), with some variations due to the different biotops ?

From left to right : C. hybridus, C. unifasciatus, C. hybridus, C. unifasciatus (Gorée), C. unifasciatus.

From left to right : 1 à 4 : C. unifasciatus, 5 : C. cacao

I hope this article will contribute a little to enhance the Senegal’s cones knowledge. I am waiting for your comments. Send me a mail. contact : Rlebeon@wanadoo.fr