The occurrence in waters around the Canary and Cape Verde Islands of Amphionides Reynaudii, the sole species of the order Amphionidacea (Crustaces: Eucarida)

              Rev. Acad. Canar. Cienc, XI (Nums. 3-4), 113-119 (1999)
THE OCCURRENCE IN WATERS AROUND THE CANARY AND CAPE VERDE
ISLANDS OF AMPHIONIDES REYNAUDII, THE SOLE SPECIES OF THE ORDER
AMPHIONIDACEA (CRUSTACEA: EUCARIDA).
J. A. Lindley* and F. Hernandez**
*Centre for Coastal and Marine Sciences, Plymouth Marine Laboratory, The Hoe, Plymouth,
PL1 3DH, Reino Unido.
**Departamento de Biologia Marina, Museo de Ciencias Naturales. OAM. Cabildo de
Tenerife, Aptdo. Correos 853, 38003 Santa Cruz de Tenerife, Canarias.
ABSTRACT
The Eucaridean Order Amphionidacea includes only one known species, Amphionides
reynaudii. One of the characteristics distinguishing the Order is strong sexual dimorphism.
This species is found in all oceans between 36°N and 36°S, the zoeas living near the surface
but the adults at great depth. A specimen of a zoea was taken during the TFMCBM/98 1 Cabo
Verde Cruise off San Nicholas island (NW of the Cape Verde Archipelago). The zoea was of
a late developmental stage originally described as the penultimate zoea but subsequent work
indicated that it was the last zoeal stage of the female. The present specimen had setose
pleopods developing within the non-setose cuticle, confirming that it is the last zoea.
RESUMEN
El Orden Eucarideo Amphionidacea, una de cuyas caracteristicas mas distintivas es su
acusado dimorfismo sexual, incluye solo una especie conocida, Amphionides reynaudii. Esta
se distribuye por todos los oceanos entre 36 N y 36 S, las zoeas cerca de la superficie,
mientras que los adultos prefieren vivir a gran profundidad. En el curso de la campana
TFMCBM/98 Cabo Verde (incluida en el Proyecto Macaronesia 2000 del Museo de Ciencias
Naturales), un especimen de zoea de este interesante orden fue recolectado en una pesca
planctonica cerca de la isla de San Nicolas (NO del Archipielago). La zoea fue originalmente
descrita como en penultima fase de desarrollo, aunque trabajos mas exhaustivos pusieron de
manifiesto que se trataba de la fase final de una hembra (9), puesto que el especimen
presentaba pleopodos setosos desarrollandose dentro de una cuticula no setosa, caracteristica
que confirma este estadio.
1 This cruise has been supported by the Macaronesia 2000 Program of the Natural Sciences Museum of Tenerife
(O.A.M.C.)
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1.- INTRODUCTION
Amphionides renaudii was first described as Amphion reynaudii on the basis of larvae
from the Indian Ocean (MILNE EDWARDS [5]). Subsequently larvae were identified as 4
species before the adult was described and named as Amphionides valdiviae ZIMMER [9]. A
full account of larval development (HEEGAARD [3]) demonstrated that all the previously
described forms could be referred to a single species with a distribution in all oceans between
36°N and 36°S.
WILLIAMSON [7] has given an account of the varying opinions as to the taxonomic
position of Amphionides. Initially it was thought that they were close to the Phyllosoma larvae
of Palinuridea, then that they were larvae of Polycheles (Eryoneicus larvae are now known to
be the larvae of this genus), or related to Sergestids or the Caridean larval genus Eretmocaris.
Following the description of the adult, Amphionides was considered to be a Caridean, albeit
forming a distinctive family or sub-tribe. WILLIAMSON raised it to the status of an Order,
the Amphionidacea, on the basis of sexual dimorphism, the distinctive form of thoracic brood
pouch in the female, the thoracic limbs, the abdominal pleura, the branchiae and the nature of
the larvae. The Amphionidacea thus become one of three Orders, with the Euphausiacea and
Decapoda, in the Superorder Eucarida,
The larval stages mainly occur in the epipelagic zone. HEEGAARD [3] concluded
that they were most abundant in the upper 30m, WILLIAMSON [7] found that most occurred
above 100m. No evidence has been presented for differences in vertical distributions between
these stages. The adults however usually occur much deeper. ZIMMER [9] found them at
about 4000m depth. HEEGAARD [3] gave a range of 2000-5000m where he would expect
new record of adults, although the he recorded one adult female at about 60m depth.
WILLIAMSON found specimens in closing nets sampling between 700 and 1700m and open
nets sampling from 3700m depth to the surface. GURNEY [1] recorded 3 specimens from
between 2700m and the surface.
1.1. Records from the eastern Atlantic near the Canary and Cape Verde Islands
A specimen was taken in a diurnal haul (24C98D reference) with a triple no-closing
net WP-2 (200 u standard for the mesozooplankton with a diameter open mouth 56 cm/by net,
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6658 m3 water filtered in 1000 meters of haul selon the information of a flowmeter installed)
between 1000 m depth to surface (bottom 1200 meters) at the station 16° 38' 90" N and 24°
49' 36" W (off San Nicolau Island) at 15,55 p.m. on September 24, 1998 during a
TFMCBM/ 98 Cabo Verde-Cruise, supported by the Natural Sciences Museum of Tenerife on
the "Corvette" ship as part of a MACARONESIA 2000 PROGRAM. The specimen captured
was identified as a late zoea stage of the type described by HEEGAARD [3] as a zoea XII.
There are previous records of the species near the Canary Islands and Cape Verde
Islands from ZIMMER [9], GURNEY [1], HEEGAARD [3] and WILLIAMSON [7].
ZIMMER recorded adults near Madeira and off Cape Palmas. GURNEY' S records were of
larvae from the Canary Islands (29°27'N, 15°07'W) and Cape Verde Islands (14°39'N
25°51'W). HEEGAARD recorded both adults and larvae near the Canary Islands.
WILLIAMSON examined specimens from samples taken south-west of Cape Verde within
the area 10°14'-11°35'N, 19°51'-21°26'W and one sample from south-west of the Canary
Islands (25°00'N, 19°36'W). He also reported that metamorphosed specimens were taken in
the region of Cape Verde, Senegal by FOXTON (unpublished) (in Addendum to
WILLIAMSON [7]).
1.2. Morphology
The early zoea stages closely resemble caridean larvae (HEEGAARD [3]). According
to WILLIAMSON [8] thoracopods 1 and 2 (the first and second maxillipeds) are well
separated in Amphionides but are close together in the Caridea. At about the sixth zoea stage
the carapace starts to become dorso-ventrally flattened, a characteristic that contributed to the
suggestion of a relationship to phyllosoma larvae (WILLIAMSON [7]). No chelae or
pseudochelae develop in the later stages in contrast with the late zoea stages of Caridea.
The work of GURNEY [1 & 2] and LEBOUR [4] indicated that there were 9 zoea
stages but HEEGAARD described 13 "mysis" (zoea) stages. WILLIAMSON [7] concluded
that the number of stages may be variable and that HEEGAARD's stages XII and XIII are not
successive stages but the last zoeal stages of the female and male respectively. There is one
immature post-larval stage (megalopa) in the female. The zoeas range in size from 4.0mm to
25.0mm (male last zoea). HEEGAARD [3] concluded that the first zoea was the first free
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living stage. However GURNEY [2] noted the occurrence of a stage with no rostrum without
further description or illustration and HEEGAARD speculated on the possibility of the
existence of a short-lived "promysis" (prezoea) stage.
The carapace of the adult female is extremely thin and nearly always badly damaged
in net caught specimens. The descriptions by GURNEY [1], HEEGAARD [3] and
WILLIAMSON [7] have depended on examination of several specimens with differing
patterns of damage. The carapace is inflated to form what WILLIAMSON [7] interpreted as a
brood chamber. The absence of eggs from any of the >100 specimens examined by various
authors is evidence that the eggs are not attached to the pleopods, as they are in most
decapods, but are retained loose in the thoracic brood chamber and have been lost when the
delicate carapace was damaged. The mouthparts and digestive system are vestigial and none
of the thoracic limbs are functional maxillipeds so it is unlikely that the adult female feeds.
The abdomen and pleopods are robust in contrast with the thorax. The first pleopods are much
enlarged, uniramous, U-shaped at the distal end and reaches far forward into the carapace.
They may form a partial closure of the brood chamber in life (WILLIAMSON [7]). As yet
there is no record of an undamaged female and no specimen has been taken with eggs
retained in the brood chamber. Availability of such specimens would provide the opportunity
to confirm aspects of the biology of the species that remain uncertain.
WILLIAMSON [7] concluded that the stage described by ZIMMER [9] and
GURNEY [2] as the female and by HEEGAARD [3] as the first post-larval stage, is in fact
the male. If it were not sexually mature it would be considered to be a megalopa according to
Williamson's (1969) system. The carapace is more inflated than in the zoeal stages but less so
than in the female, The mouthparts and alimentary system appear fully functional, but there
are no setae on the epoxites of the 2 to 7 thoracopods. Th
resembles the others except for the small size of the endopod.
The pleopods are setose and the 1
The present specimen is illustrated in Figure 1 . The total length of the specimen is
24.1mm, the carapace length is 13.3mm and its width is 4.3mm, the abdomen was 7.1mm
long and the telson length is 3.7mm. The equivalent measurements for this stage given by
HEEGAARD [3] were 23mm, 13mm, 4mm, 8mm and 2.5mm respectively. HEEGAARD
gave a full description of the appendages of this stage. There are setose pleopods developing
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within the non-setose cuticle, confirming WILLIAMSON'S [7] opinion that this is indeed the
last zoea stage.
Examples of earlier zoea stages described by HEEGAARD [3] and the adult female,
adapting the figure from WILLIAMSON [7] with amendments consistent with
HEEGAARD'S figure of that stage are given in Figure 2.
2. REFERENCES
[1] GURNEY, R., 1936. Larvae of decapod Crustacea, 2. Amphionidae. Discovery Rep. 12,
392-399.
[2] GURNEY, R., 1942. The larvae of the decapod Crustacea. Ray Society. 308pp.
[3] HEEGAARD, P., 1969. Larvae of decapod Crustacea. 2. Amphionidae. Dana Rep., 11, 1-
82.
[4] LEBOUR, M.V., 1950. Notes on some larval decapods (Crustacea) from Bermuda.-II
Proc. Zool. Soc. Lond. 120, 743-747.
[5] MILNE EDWARDS, H., 1832. Note sur un noveau genre de Crustaces de l'ordre des
Stomatopodes. Annls. Soc. Ent. France. 1, 336-340.
[6] WILLIAMSON, D.I., 1969. Names of larvae in the Decapoda and Euphausiacea.
Crustaceana, 16, 210-213.
[7] WILLIAMSON, D.I., 1973. Amphionides reynaudii (H. Milne Edwards), representative of
a proposed new order of Eucaridan Malacostraca. Crustaceana, 25, 35-50.
[8] WILLIAMSON, D.I., 1982, Larval morphology and Diversity. In: The Biology of
Crustacea, Vol. 2, Embryology, Morphology and Genetics. D.E. Bliss ed., Academic
Press, New York, pp 43-1 10.
[9] ZIMMER, C, 1904. Amphionides valdiviae n.g. n. sp. Zool. Anz. 28, 225-228.
3. ACKNOWLEDGEMENTS
Special mention to our colleagues in the TFMCBM/98 Cape Vert Cruise, Dr.
Sebastian Jimenez and Mr. Pedro Ortega for their collaboration during the sampling
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Figure 1. Amphionides reynaudii zoea from sample 24C98 D (1000-0m) in the TFMCBM/98
Crusie. (a) Lateral view with bases of thoracopods shown and numbered (1 is a maxilliped, 2
and 3 were described by Heegaard as maxillipeds but are not functional feeding appendages
ansd are 4-7 are pereiopods) details of appendages are described by Heegaard (1969). (b)
Dorsal view of carapace. Scale bar =5mm
Figure 2 (next page). Amphionides reynaudii. a) Zoea I after Heegaard (1969), scale bar
lmm, b) Zoea II after Heegaard (1969) scale bar 1mm, c) adult female modified from
Williamson (1973) and Heegaard (1969). Scale bar 5mm.
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a
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