Rediscovery Of Cymodocella Algoense From South Africa (Crustacea: Isopoda: Sphaeromatidae)

6 Pages·1996·2 MB·

by  B Kensley

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PROCEEDINGS OF THE BIOLOGICAL SOCIETY OF WASHINGTON
109(l):91-96. 1996
Rediscovery of Cymodocella algoense from South Africa
(Crustacea: Isopoda: Sphaeromatidae)
Brian Kensley and Mary Bursey
(BK) Department of Invertebrate Zoology, National Museum of Natural History,
Smithsonian Institution, Washington, D.C. 20560, U.S.A.;
(MB) East London Museum, P.O. Box 11021, Southernwood 5213, South Africa
—
Abstract. The tiny sphaeromatid isopod Cymodocella algoense, which is
characterized by a bulbous tubular posterior pleotelson, is rediscovered 120
years after having been described from a single specimen from Algoa Bay.
The new material was collected from the delta ofthe Nahoon River on the east
coast of South Africa.
Stebbing (1875) described a single tiny Family Sphaeromatidae
sphaeromatid isopod taken from the sand Subfamily Dynameninae
and fragments in a collection of sponges Cymodocella algoense (Stebbing, 1875)
and gorgonians sent to him from Algoa Figs. 1-3
Bay, South Africa. The species has not been
recorded since. In 1910, Stebbing cast some Sphaeroma algoense Stebbing, 1875:187,
doubt on the accuracy of the original local- pi. 15, fig. 3. —
Cymodocella algoensis. Stebbing, 1905:
ity data. Barnard (1940), in his list of Cy-
modocella species from South Africa, men- 30; 1910:4—30.—Barnard, 1940:492 (spe-
C cies dubia). Bruce, 1995:14.
tions algoensis with the annotation "spe-
—
cies dubia,juv." thereby casting uncertainty
Material. 5 non-ovigerous ?, total
on its identity. length 2.9-4.0 mm, dissected ? 3.3 mm;
In the course of an ecological survey of Nahoon Riverestuary flood-tidal delta, East
the benthos of the flood-tidal delta of the London, South Africa, 1.6 m at bottom of
Nahoon River estuary, East London, on the channel at mouth, low spring tide, coarse
east coast of South Africa, seven intertidal sand, coll. M. Bursey, 22 Feb 1993.—
and seven subtidal sites were sampled by non-ovigerous $, total length 3.0^.0 mm;
portable hydraulic suction sampler. Seven Nahoon River estuary flood-tidal delta. East
tiny adult female sphaeromatids were col- London, South Africa, 2 m on steep sloping
lected at two of the sites. On examination bank 500 m from mouth, low spring tide,
they proved to be the long forgotten Cy- sand, coll. M. B—ursey, 8 Feb 1993.
modocella algoense, which is here rede- Description. Female: Body dorsally
scribed. The Nahoon River estuary is about strongly arched; surface of cephalon, per-
200 km north-east of the type locality, Al- eon, and pleon smooth. Epistome roughly
goa Bay. Three specimens have been de- triangular, distally rounded, lateral margins
posited in the National Museum of Natural slightly convex, leading to short, rounded,
History, Smithsonian Institution (USNM diverging 'legs'. Pleotelson reaching well
253240), two in the South African Muse- beyond uropodal rami, consisting of broad,
um, Cape Town, and two in the East Lon- inflated basal half having 2 obscure, sub-
don Museum, South Africa. median protuberances, posterior half tubu-
92 PROCEEDINGS OF THE BIOLOGICAL SOCIETY OF WASHINGTON
Fig. 1. Cymodocella algoense: A, Female in dorsal view, scale = 1 mm; B, Posteriorpleon in ventral view;
C, Female in lateral view; D, Epistome; E, Antennule; F, Antenna; G, Mandible; H, Grinding surface ofman-
dibular molar; I, Mandibular palp; J, Maxilliped; K, Maxilla 1; L, Maxilla 2.
VOLUME NUMBER
109, 1 93
Fig. 2. Cymodocella algoense: A-G, Pereopods 1-7 respectively.
94 PROCEEDINGS OFTHE BIOLOGICAL SOCIETY OF WASHINGTON
Fig. 3. Cymodocella algoense: A-E, Pleopods 1-5 respectively.
lar, apically slightly narrowed with circular short plus 2 more elongate fringed spines
foramen. in spine-row; molar truncate, grinding sur-
Antennular peduncle with robust basal face subcircular, ridged, with marginal se-
article twice length of article 2, flanking tae; palp with 4 fringed setae distally on
and reaching anteriorly beyond epistome; article 2, 8 stout fringed setae on article 3.
article 3 slightly shorter and about half Maxilla 1, outer ramus with 5 broad simple
width of article 2; flagellum of 9 articles, and 4 denticulate distal spines; inner ramus
single aesthetasc present on articles 3-8. with 4 circumplumose setae. Maxilla 2, in-
Antennal peduncle of 5 articles, articles 1 ner ramus with about 12 mesiodistal cir-
and 2 short, subequal; articles 3-5 increas- cumplumose setae; outer ramus with 4
ing in length distally; flagellum of 11 arti- elongate denticulate spines distally on each
cles. Mandible with sclerotized incisor hav- lobe. Maxilliped, endite distally having 7
ing 3 cusps; lacinia mobilis with 2 cusps; 2 stout, basally circumplumose and distally
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109, 1 95
rounded setae, with single coupling hook letic, defined a second genus, Diclidocella,
on mesial margin; articles 2-5 of palp dis- to accommodate some of the species,
tomesially setose, articles 2 and 3 mesiodis- moved two southern African species to Is-
tally somewhat lobed. Pereopod 1 more ro- chyromene, and removed C. hawaiiensis
bust but shorter than following pereopods; Bruce, 1994, from the group altogether.
basis having pile of short stiff setules on The genus Cymodocella Pfeffer, 1887,
dorsal surface; ischium with several simple currently contains four species (see Bruce
C
setae on dorsal surface; merus with single 1995:5). The type species, tubicauda
stout anterodistal and posterodistal fringed Pfeffer, 1887, was redescribed by Brandt &
seta; carpus triangular, with very short free Wagele (1989). Cymodocella algoensis can
anterior margin, with stout posterodistal now be included in this group, agreeing
fringed seta; propodus with 3 stout fringed well with the revised diagnosis provided by
setae on posterior surface; dactylus having Bruce (1995). Although Stebbing's descrip-
C
bilobed accessory spine at base of unguis. tion of algoense is limited, the figure of
Pereopod 2 more slender than following the whole animal in dorsal view shows the
legs; basis with pile of short stiff spinules distinctively shaped convex-sided pleotel-
on anterior surface; ischium with 3 elongate sonic tube. The remaining four South Af-
simple setae on anterior surface; merus with rican species are ofuncertain generic status,
2 simple anterodistal setae; carpus rectan- and require redescription, given the lack of
gular, % length of propodus. Pereopods 3- detail in existing descriptions.
7 essentially similar, pereopod 7 slightly
more slender than preceding legs; basis and Acknowledgments
ischium with pile of short spinules on an-
terior surface; ischium with 4-6 elongate The firstauthorthanks Leon Engelbrecht,
simple setae on anterior surface; merus Robson Ntsabo, and Deon Smit for helping
much shorter than ischium, with 2-A simple to operate the hydraulic pump during sam-
setae on rounded anterodistal lobe; carpus pling. Dr. Niel Bruce ofthe Zoological Mu-
seum, Copenhagen, commented on the
with single bifringed seta distally, except in
pereopod 7 which has 6 bifringed setae; an- manuscript, and generously shared his un-
published work on the tube-tailed sphaero-
terior surfaces of merus, carpus, and prop-
odus having numerous short scales/spi- matids, which greatly improved this short
contribution. We are also grateful to Ms.
nules; dactylus with bifid accessory spine
at base of unguis. Pleopods 1-3 each with Marilyn Schotte for reading a draft of the
elliptical exopod bearing plumose marginal paper.
setae; endopod triangular, subequal in
length to exopod in pleopod 1, reaching Literature Cited
well beyond exopod in pleopods 2 and 3, Barnard, K. H. 1940. Contributions to the crustacean
bearing plumose marginal setae. Pleopod 4, faunaofSouth Africa. XII. Furtheradditions to
both rami pleated, exopod with single short the Tanaidacea, Isopoda, and Amphipoda, to-
distal seta. Pleopod 5, both rami pleated, gether with keys for the identification of the
exopod with transverse suture in distal half, hithe—rto recorded marine and fresh-water spe-
armed with 3 spinulose lobes. Uropod with cies. Annals of the South African Museum
32(5):381-543.
exopod freely articulating under endopod, Brandt, A., & J.-W. Wagele. 1989. Redescriptions of
elliptical, considerably shorter than endo- Cymodocella tubicauda Pfeffer, 1887, and Ex-
pod, latter distally rounded. osphaeromagigas(Leach—, 1818)(Crustacea,Is-
Male: unknown. opoda, Sphaeromatidae). Antarctic Science 1:
—
205-214.
Remarks. Bruce (1995), in a revision of Bruce, N. L. 1994. New records of marine isopod
the tube-tailed sphaeromatids, demonstrated crustac—eans (Sphaeromatidae) from Hawaiian
that the genus Cymodocella was polyphy- waters. Crustaceana 67(3):381—386.
96 PROCEEDINGS OF THE BIOLOGICAL SOCIETY OF WASHINGTON
. 1995. The taxonomy and phylogeny oftube- Stebbing, T. R. R. 1875.—On some new exotic sessile-
tailed sphaeromatid isopods (Crustacea) with eyed crustaceans. Annals and Magazine of
descriptions of new species and a new genus Natural History (4)15:184-188.
—
from southernAustralia. Ophelia43:127-180. . 1905. On the Isopoda. Pages 1-64, in W. A.
Harrison, K., & J. P. Ellis. 1991. The genera of the Herdman, Report to the GovernmentofCeylon
Sphaeromatidae(—Crustacea: Isopoda): akeyand on thePearlOysterFisheriesoftheGulfofMa-
distribution list. Invertebrate Taxonomy 5: naar. Supplementary Report 23.
915-952. . 1910. G—eneral catalogue of South African
Pfeffer, G. 1887. Die Krebse von Siid-Georgien nach Crustacea. Annals of the South African Mu-
der A—usbeute der Deutschen Station 1882- seum 6(4):281-593.
1883. Jahrbuch der Hamburgischen Wissen-
schaftlichen Anstalten 4:43-150.