First record of the species Microjassa cumbrensis (Stebbing & Robertson, 1891) (Amphipoda, Ischyroceridar) from the Canary Islands (NE Atlantic ocean)

              Rev. Acad. Canar. Cienc, XXII (Num. 3), 75-78 (2010) (publicado en octubre de 2011)
FIRST RECORD OF THE SPECIES Microjassa cumbrensis
(STEBBING & ROBERTSON, 1891)
(AMPHIPODA, ISCHYROCERIDAE)
FROM THE CANARY ISLANDS (NE ATLANTIC OCEAN)
E. Ramos & R. Riera*
Centra de Investigaciones Medioambientales del Atlantico (CIMA SL)
Arzobispo Elias Yanes, 44, 38206 La Laguna, Tenerife, Canary Islands, Spain
* corresponding author: rodrigo(§^cimacanarias.com
ABSTRACT
The amphipod species Microjassa cumbrensis (Stebbing & Robertson, 1891) is first
recorded for the Canarian archipelago. This species has been commonly collected in the East
Atlantic Ocean (coasts of France and England) and the Mediterrranean Sea throughout the
last decades. Moreover, accompanying fauna data and sedimentary characteristics of the
sampling station are presented.
Key words: Amphipoda, Gammaridea, Microjassa, La Gomera, Canary Islands.
RESUMEN
Se cita por por primera vez la especie Microjassa cumbrensis (Stebbing & Robertson,
1891) para las islas Canarias. Esta especie se ha colectado de forma periodica en las ultimas
decadas en las costas de Francia e Inglaterra, asi como en el mar Mediterraneo. Ademas, se
aportan datos de la fauna acompanante y de las caracteristicas del sedimento de la estacion
de muestreo.
Palabras clave: Amphipoda, Gammaridea, Microjassa, La Gomera, Islas Canarias.
1. INTRODUCTION
In the last decades, sandy seabeds have been neglected in ecological and taxonomic
studies in the Macaronesian region. However, several recent papers have been published relat-ed
to ecology and taxonomy of macro- and meiofaunal assemblages, mainly foccused on poly-chaetes
(Madeira, Nunez et al [4]; Selvagens Islands (Nunez et al [5]; Cape Verde Islands,
Nunez et al [6] and the Canarian archipelago, Brito et al [2]). Unfortunately, there are still
scarce information about other macrofaunal components (e.g. Amphipoda, Oligochaeta) of the
infauna from sandy subtidal seabeds in the Macaronesian region. Thus, biodiversity records
are still far from other extensively studied areas (e.g. Atlantic coasts of France and Britain).
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One of the taxonomic groups that belongs to macrofaunal assemblages in sediments
are amphipods (gammarids and caprellids). This taxa is mainly composed by surface-deposit
feeders that inhabit in the first layers of the sediment surface (Brito [1]), however,
amphipods have been received little attention in the last years in ecological and taxonomic
studies (Riera etal [8, 9], Ortiz etal [7]).
During an ecological study of the sediments in San Sebastian de La Gomera, one
specimen of an unpreviously described species of gammarid from the Canary Islands was
collected. Microjassa cumbrensis has been formerly described in the Atlantic Ocean and the
Mediterranean Sea (Conradi & GonzAlez [3]).
2. MATERIAL AND METHODS
Samples were collected by means of a "Cak Foster" dredge, with 28-litres capacity.
Samples were fixed by 4% formaldehyde during 48 hours and then, sieved in a 0.5 mm mesh
size. Specimens were separated under a stereomicroscope and preserved in 70° ethanol.
Specimens were identified by means of a stereomicroscope Nikon SMZ-800 and pictures
were taken with an attached camera (EOS-500D).
The studied specimens were stored in the invertebrate collection of CIMA (Centro de
Investigaciones Medioambientales del Atlantico SL).
A
an
+
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c_Jo1»_r „.„„,
Figure 1.- Map showing sampling station (•).
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3. SYSTEMATICS
Order AMPHIPODA Latreille, 1816
Suborder Gammaridea Dana, 1852
Family Ischyroceridae Stebbing, 1899
Microjassa cumbrensis (Stebbing & Robertson, 1891)
(Figure 2)
Podocerus cumbrensis Stebbing & Robertson, 1891 : 38.
Microjassa cumbrensis Stebbing, 1899: 240.
Studied material.- La Gomera, off San Sebastian de La Gomera harbour (coordinates:
17°1 1 '08"N/28°07'95"W), 1 female, March 2009, 30 m deep.
Sediment characterization.- Coarse sands (51%). Organic matter (0.58%).
Description.- Length 2.8 mm, whitish. Coxal plate 1 small, plates 2-4 very large and
equal, being broad the last one (plate 4). Head triangular, with broad lateral lobes. Eyes large
and round. Antennae with few long setae (10-15); antenna 1 short, with flagellum articulat-ed
(3-4) and accesory flagellum very small (1 -articulate). Antenna 2 almost equal than 1, fla-gellum
articulated (3-4). Gnathopod 1 propod ovoid, palm with 3 slender spines, dactylus
slender with inner margin with tooth. Gnathopod 2 similar to 1, except merus with an
enlarged posterior lobe. Pereopods long and slender, 5-7 basis broad and slightly oval.
Uropods 1-2 with outer ramus slightly shorter than inner. Uropod 3 with elongate peduncle,
inner ramus with an apical spine, outer ramus with distal denticles.
Figure 2.- Microjassa cumbrensis. Female. Scale: 0.5 mm.
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Accompanying fauna.- The sampling station was dominated by the caprellids
Phtisica marina (33 ind.) and Pariambus typicus (30 ind.). Other species with noticeable
densities were the gammarid Megamphopus cornutus (13 ind.) and the caprellid
Pseudoprotella phasma (13 ind.).
Distribution.- Mediterranean Sea. East Atlantic Ocean (Conradi & Gonzalez [3]).
4. ACKNOWLEDGEMENTS
We are grateful to Dr. Manolo Ortiz (Centro de Investigaciones Marinas, University
of La Habana, Cuba) for his encouragement and interchange of ideas. To Dr. Oscar Perez
(Centro de Investigaciones Medioambientales del Atlantico, CIMA SL) for map preparation.
5. REFERENCES
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