Okera, W.

English

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18
A key for the identification of economically important
West African marine and freshwtershrirllp-like crustaceans,
W0 Okera
(English version of Professor Theodore Mond'a19.66 key,
with some modification)
Introduction
Professor Monod in his paper on the shrimps and crabs of
West African coast, gives a useful illustrated key for the
identification of marine and freshwater shiirp-l-ike
crustaceans éncountered in the industrial and ärtisanal
fishery. As a first step in the bionomic studies of some
of the marine shrimps, as well as in the efforts to build
up a reference collection of crustaceans, it became necessa
ry to translate Mood's key into English so asto make it
readily usable. A few changes were later-introduced in the
key durThgtbe course of its apiication iii the ìdentifica..
tion of marine and estuarine species. Some further-changes
in the kòy&ppear necessary. For instance, Heterocar.pus
ensif er is not keyed in the text, though figured by the
author. Two freshwater speciés oÍ' Macrobrachlum (M. foal
and M0 lujae) reported from Zaire (Hoithuis, 1951) are
also not in the key0 Pe pe the status of these two
species is doubtful or had chanab the time Monod wrote
his work. The following key may therefore undergo some
further changes, although in its present form, it is quite
satisfactory for the identification of the common specie.s0
19
Shririp-like crustaoeans(Deoapoda-Nataitia)
Pleura (side plates) Qf th second ab.dominal egriont not
overlapp..rig tìos of the first segmeìt Third pair of
perolopods (walking legs) chelate (with pincers); fourth.
and fifth pereopods not chelato ,Penaeidea(rnarine)q A
P1eura of second abdominal segrnenb. over.lupping those of
ehe first arid third segment Third pair of pereiopods
non-chelte, that is, third fovrth and fifbl' perelo-
A Pen.eidea
I Pleopods (swimrnng legs) 3 to un1ra'iou (not
branched) Sicyonia aieatt
- P1eopod 3 to 5 hiramoua brrnched) GOQOUv 2
2 Rbsrum with teeth ondor S ala ud ventral surfaces 3
- Rostrum with teeth on dor.:&lurfae.. on1y
3 Coxa of pereiopod I to 3 each :1Te1son
with 3 peurs of spineò (ofben d.aiodged or broken).
Sixbh abdominal segment without e. groove on each
side of the median carina Lower surface ci' the
rostrum with a single tOOthU Carapace and abdom-
na! egrnents with Cro.risverse blush-brown bands
violet-blue margins of uropods fringed with red-
setacU (Commonly called the biger-shi imp ci
langostino) Penueus kerathurus
- Coxa o± pereiopod i to 3 each without a spine
Telson withouL p1nesU Sixth abdon'm.nal segment with
a groove on each side ci' the median carina; lower
surface of the. rpstrum with 2 teeth Cöiou brown
or pinkish brownU (Common names the shrimp, pink or
rose or ardmel shriup) Pcnaous duorarum otialis
+ Cervical groove well marked, reaching the medio-
dorsal lineU A pos--cibita]. pine Antennularflagella long (=,caapaco.Legth) cQmres5ed widgroove like Solenoia nembranaeum
Cervical gioove incompletoU Post-orbibal pirie
absentU Antennular flagellt hÓrt, :cy!j.nd..jca1 and
not grooved .U. .. O Q Q Q Q O O Q Q Q U U Q O Q Q U U Q U Q Q U U 5
Mct' td b.c confused with baciai spines on Ist and 2nd
p,ereiopods, always....present in .Penaeus
2O
5' ,Ddrsal surface of .to rostrwn Vdth 3 teth0 Hepatic
spine absent Q Q Q Q Q Q Q Q Q 6
Dorsal surface of the rostrum with5 teet'h0 Hepatic
spule present O Q Q Q Q Q
,
Q O Q Q O Q Q Q Q Q Q Q Q Q O Q Q '0 8
G Carapace strongly su1Jpuie 'Fourth pereiopod with
an epipodite, th2,rd with a podobranch
Plesiopenaeus edwardsianus
Carapace almost smoothQ Fourth pereiopod without
epipodite; third without a p. obranch00 Ari teus' 7
7 Upper part of the internlhalf öl the petama
entire 0000000000Q000000QQ Aristeus antennatu
Upper part of the internal h'lf of the petasma
deeply notched Aristeus arideñs
Antennularscale present;',00lour greyish OQOUQOOQOGOQO 9
Antennular scale absent;..colour bloothred
Aristasomorpha foliacea
9 Telson with one pair of spiniform teeth fixed
sifbapioally (apex trífido) and one pair of mobile
spines (deéiduous; ofton Ínvisible)Q Fifth pair.of
pere±opods similar to the preceding one not passing
beyond 2/3 of the anterinal scale, rostrum almost
'straight or.oìly. slightly curved 0000000 OQOÓ0QQ0091O
Telson with four pairs of subapicol mobile spines0
Fifth pair of pereiopods thin, reaching boyond the
extremity- of antennal scal ,:Rostrum sigmoid,
with a long non-toQthed apex0 Rostral formula
11/O Parapenue2psis atlantica
IO flo'strurij relativelrr short and stxaight0 Carapace
without longitudinal and transverse sutures0 Digits
of pereiopods k and 5 clawed0 Petasma asymmetric0
Rostal formula 71O/O QQQo naeo sis Th]e'S1
Capc with 'longitudinal and,
digits of .pereiopod. k and 5 '1 late pear-'haped'0
Petasma symmetric0 Rostral 'fórmüïa 8/o
Paiapenasue longirostris
B0 Caridea
First two par'o'f pereiopods moi-'e br l'ess'ïdntical;
carpe ( carpus) of 2nd pereiopod not subdivided 2
First two pair of perciopods moro or lese dissimilar;
carpe of 2nd. pereiopod entire or subdivided 8
2 Pincers of first two pereiopods oblique, with tho
digits of the chelae spoonshaped and carrying
tuf t of hriot1es Mandible without palpsQ(Freshwater Atyldac ) Q 0 Q Q Q Q Q Q O Q Q Q O O Q O Q Q Q O Q Q Q O Q Q Q Q Q Q 3
21
Pincers of first two pere±opodswith pro1ongc3. carpe
(digite normal,wlthout tufts of bristles)0 Mandible
with palp0 (I4arine forris) 6
3 Lateral rostral groove situated from the middle of
the rostrum with the former's outer margin smooth
or with an obtuse dent,. Lower internal margin of
merus of pereiopocl without a stub; telson about
t wice as long as +
Lateral rostral groove situated from the base of
the rostrum, with an upturned strong dent-like
projection on its outer edge; lower internal
margin of merus of perelopod with a stub; telâon
almost as wide as long .. ya abonensis
k Latal rôtral».groove wjder and rounded posteriorly.;
bristles, on the telson edge medium and in a single
series eo.00.a.o.00000e.00.oeoo.o.ee0000,0000.o.oeoo.óøo...5
Lateral rostral groove narrow and pointed poste-'
riorly, 'borderèd on its outer margin by an obtuse
dnt in front of which the rostrum narrows;
bristles ÖXT th.è posterior edge of telson medium
and in 2 series .00000000e'.e.OoOo Atya scabr
5 Rostrum sufficiently narrow, particu1ar.y at. the
sharp d'istal part. Lateral rostral groovs
shallow and rounded0 Dorsal rostral 'arina
straight or slihtly concave; ventral rostal
surface oni.y slightly carinated with sorne
dêntìcui.es-... Stub on the merus of ..porei.Qpo.d.
sufficiently pronounced and cornified apically000
Atya africane:
- Rostruríi'wider and slightly rounded;l'a'teral grooves.
sufficiently deep0 Dorsal carina of rostruinnarrow
and quite inflexed at the extremity0 Stub on
walking leg low and slightly corniÌed
.itya intermedia
G Pereiopod 3 to 5 not abnormally long; pèrèiopöd
I to 5 without exopodite0 Dorsal, and ventral
surfaces of rostrum toothed Qpl'óphoridae 7
- Pereiopod 3 to 5 extremely long, 5th legs without
exopodite, röstrurn with teeth along dorsal surface
only, the ventral surface siiply..setose
Nematocarcimï
7 3rd abdominal somite only carona' poterior
margins f.kth and 5thab'drûinal om',i:be
denticulaed0' Rostral formula Ï316/8:.110
Photophores present 0000000000 Systellaspis debilis
22
OnJy firt abdominal sonilte without a ca±'ína;
posteriormugin of kth £U1d 5th abdominal somites
..entireQ Rostral formula 5-11/3.7. No photophores
Acathephyrc
7
Çarp of 2nd. pereiopod aivided ±I1 2 Or more parts( marine, especia11y3eep) 9
Carp of 2nd per?lOpod siìp1e, not divided (marine,
estuarin, frewater). . Palaernonidae o i8
Pincers of f±t tir of .pereiopb1s' pQninert at
least on onesid?, rostrum short or long 10
Pincers o± first par of pereiopods microscopic
or absiat otrum]ays passes the eye, often
very lóng ith orsal and. ventral teeth .:oaoco
Pndalidae 00 000 G O 0Go GOGO 00 11
IO Right first pereiopowitha pinôéret:withdut0
Rostrum short riö passing the eye, apex bifid thd
without teeth on dorsal and ventral surfaces
Processidac (gen0 ________)
Both the first pereiopods chelate. Rostrurnîery
long with dorsal and entra1'tth (Hippolytidae)
Hippo1smata (Exhípolysmata) hastatoides
11 Teeth at th base of the dorsal rostral surface oe000 12
Teeth along the whole length of the dorsal
rostral surftce 0 .ø S 000000G O 00 50000 .00OD. 15
12 Posterior edge of 3rd abdominal segment with a
median sharp too.th o..søaeoeooe.oe.o-o.,o.00.e..o..00,_l3
PoBterior edge oÍ'3rd abdominal segmenïnded 1k
13 Ventral rostral urface with numerous teeth (2B_Li5),
average size (up to 13cm) Plesionika ensis
Ventral rostral surface with fewer toeth (9-1l),
size large (up bo 27cm)0b0Ò00n Plesionika williamsi
12+ Carapace at the very most with aee1le iaLteral
carina along the brthichial region0 Pereiopods.:;
I to k with epipòdites Rostrum with more than20 ventral teeth Plesionika martia
'Craace ith à strong iatral cina alo the
branchial region0 Pereiopods i to 3 rith epipoites0
Rostrum jth-1s than 20 ventral teeth000000000Pleonika caririata
15 Ventral rostral teeth spinifo±m and eparate0
Second pair of perelopods very unequal3 Third
abdominal segment with a dorsal median longitudinal
carina Plesionikaheteçs
Ventral surface of the rostrum serrated with the
teeth closely: set or else rostrum er short with
less than 10 ventral teeth. Second pair of
pereiopods similar0 Third abdominal segment
roundòd dorsally, without a carina 16
16 orun short (< carapace) and wide, witl less than
"àic teeth which donotform a serrated'margin
Plesionika acanlhonotu
Rostrum lon> carapace), narrow and"needlelikè,
itha.serratedven'traimth'gin 17
i7 t1't the base Qf the doiëal margin of the
'dsrum larger and of different form., ' Epipodites
on pereiopods I to k e...... Plesionika edwardeli
Dorsal and ventral margins of the rostrum alike,
serrated 'and the spines closely set; basal spines
of dorsal rostral margin .nôt 'different from
others. Epipodites ab,sent"on pereiöpods
Parapandalus narval
18 Supraorbital spine present (freshwater)
Desmocaris trispinosa
Supraorbital spine.absent c.e.o ...'.......... 13
19 Branchiostegal spine absent,
Branchiostegal spine present
20 Digits of pereiopos 3' to 5
Digits of periopods 3 to 5
Brachycarpus biuiculatus
23
hepatic spine present . 20
hepatic spine absent... a8
sirrple (Macrobrachium).. 21
with 2 claws ........
(marine littoral)
21 Length of carpusof second'péreiopod),.length of'
'meus' e G GO OC C C Q O C C C C O O O O O C 00 S G S O CO O O G O 50 U G O O S .e0 22
'Carpus of second pereiopod shorter thçcn merus'..oeaeoo 27
The key for' Macrobrachium is not very satisfactory, if
the carp and merus of the second pereîopod are more or
less equal0 For correct'identification adult males
should be used. Ovigerous females fall into two groups:'
eithere those with eggs eriall (<.1mm) and numerous
(chevalieri felicinum9 macrobrachion, vollënhovenii
zariquieyiT 'or bhose with fewer but large (23mm) eggs
cdens sollaudi'i)
*In th ¿''e»cf 'M0 vIlexihovenii, the carpus and inerus
are practically equal0
2k
22Adu1t::ml. with pincers o second peropQds very
ci1ferenb in size and shae di o.1 smler one
stronSl urved cúid gaping with space betfeen them
filled by stlf f bristles arising from the dtgits1
margins Q Macrobrachiuw feliQ1m
Adult male with pincers of écond pereiopòds lik
in size.and,shape; the digits are neither recurcred
flor gaping Q 8 0 3 8 0 0 3 8 8
23 Adult iiale with part of second pereiopo.d. padded
(on lower margin of ruerus or else the digits)0
Eggs nurnerovs and suiali tinn diameter)
Second pereiopod of adlt male whout Iio pad8
ggs fewer and larger (23mm .diarnetr) 9893 ,QDQO 2
2k Rostrum shorter than theantennuiar.pedice;
dorsal toeì at base of rostvum more robus and
erect than others Second pereopod of adult
male massive with rierus dilated and very hairy on
lowe surfao8 Carpus and pincers leseT hairy
than merus, digits not so haìry as palm (freshwater)80
93383 Machrobrachiurn chevalìeri.
Rostrum slender ing extreiiity of antennular
peduxicle; basal dörsal teeth of roàt,rum not verydifferent from rest, Second pereioodc.fff1aTLeL.
slender with an elongated merus, but only digits
of this leg are hairy (velvety f eitlik
the others are bare or wth sone isolated setae(fresh and brackish waters)33308 Macrobraehiuni
macrobrach ion
25 Carpus cf 2nd pereiopod always disinct.1.y .ionger
than palm (freshwater) Nacrobrachium collaudii
Carpus of 2nd pereiopod also long or else shorto,
than paliri 8 3 0 ii 6 0 3 0 J 8 Q O O Q Q 3 8 3 0 0 3 8 8 Q 3 9 3 8 0 8 3 0 0 3 8 0 ¿6
aG.. Space hetwen two pairs o± telson spines longer
than that separahing the two anterior pairs of
spines3 Second persiopod with carpu d1tinctly.
longer than merus (freshuer)
083990 Macrohraeliitun duxSpace been bwo pa.s of belson spines jttsb a
long or slighbly shorter bhan thab separating the
bwo anterior paiisof sins0 Second peroo pod
vith carpus as len5 as or only jvst longer than
ilerus (i.jeshwv ier) 88090 Ñacobrachium 3ido1U
This charìcter does not seem be be very ditinct0
25
2? Digits of 2nd pereioiod length oi palm and
without a large conica]. tooth .nternally Small
ei.zc (up to about 65mm)Q (Freshwater)
Macrobraohiuiii iei
Digits of 2nd perciopod notably shorter than the
palm with a large tooth internally0 Large size
(up to 182mm) (Fresh and brackish water)
MQ vollenhovenij
28 MandibuJ.arpLipwith twojoints 29
-, Mandibular paip with three joints 31
29 Branchioctegal groove ctbsent, Two apical setae at
extremity of toison vert lge Appendix interna
on endopoclite of male pleopod i
Leandor tenuicornis
Branehiostafgroovepresent0 Apîcal.setae o'
telson small ndix interna on endepodite of
male pleopocl i absent 30
30 Pincers of 2nd pereiopod a little greater than
carpus0 Rostral apex emarginate usually with 7 to .8dorsal teeth of which 2 are above: (on ?.) carapace
and e3rd. immediately above orbit0 Uually
ventral rostral teeth (littoÑJ) 0'0Paiaemon
(PalaewcIe)
Pincers of 2nd pox'eiopod notably smaller thafl.
carpus0 One dorsal rostral t'oóth bhind orbit;
rostral apex slender' and drawn out0 (Brackish
water) alaemon (Paiaeander) mc'ulatu
31 Branchiostegal groove bent0 Digits..of iDerciopods3 to 5 very slender and oLongated (> carpuapropo'dus)Rostrum slender and long, bent ti.pward.s0 (Mainly
marine but also occurs in brackish waters)
PJ.aepion (Nematopalaenion) hastaLuc
33rcLnchiostegal groove present0 Digits of
preiopods o 5 srialler han propodae0(Mariri;' European reaching Cape Blanc)
Palaemon (Palsemon) 'serratus
References
HO1thUIC? L0B8 (1951) The caridan crustacee. of tropical
West Africa0 Atlantide Rep0 2
Monod Ph0 (1966) Crevettes et Crabes de la cote
occidentale de UAfriquo0 Memoir IFAN No0 77


A key for the identification of economically important West African marine and freshwater shrimp-like crustaceans

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A key for the identification of economically important West African marine and freshwater shrimp-like crustaceans

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