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Vol. 52, 2013
Naupliar development of Pseudocyclops
sp. (Copepoda: Calanoida: Pseudocyclopidae): description of an unusual
set of character states
Frank
D Ferrari1, Hans-Uwe Dahms2*, Pawana Kangtia3,
Supawadee Chullasorn3 and
Mark Schick4
11826
Deer Dr., McLean, VA 22101, USA
2Green Life Science Department, College of
Convergence, Sangmyung University, 7 Hongij-dong, Jongno-gu, Seoul
110-743, Republic of Korea
3Department of Biology, Faculty of Science,
Ramkhamhaeng University, Bangkok 10240, Thailand
4John G. Shedd Aquarium, 1200 S. Lake Shore Drive,
Chicago, IL 60605, USA
Abstract
Background: Naupliar development is
known for only one other species of the calanoid taxon Pseudocyclopidae
as yet.
Results: Six naupliar stages are described from an
as yet unnamed population of Pseudocyclops
cultured at the John G. Shedd Aquarium in Chicago, IL. The naupliar
body is divided into a deep anterior section and a shallow posterior
section, although the posterior section is poorly defined at NI. The
posterior section bears a long, thin mediodorsal seta; short thick
setae are added during molts to NIII ~ NV. The posterior section does
not bear limb buds except for the caudal ramus and is presumed to
represent the anal segment of the copepod. Throughout
naupliar development, the antennule is five-segmented, a uniquely high
number for a calanoid copepod. The distal segment is broadened, and
three proximal segments are foreshortened during the molt to NIII, and
remain so thereafter. Setae are added dorsally and ventrally to the
distal segment during each molt. The naupliar arthrite is a simple,
seta-like structure on the coxa of the antenna of all naupliar stages.
On the exopod of the antenna, setae are added to the segment adjacent
to the proximal one during molts to NIV ~ NVI in a manner consistent
with the model of ramal patterning. The gnathobase is added to the coxa
of the mandible during the molt to NIV, but its ventral attenuations
are lost during the molt to NVI. The endopod of the mandible
significantly changes between stages NIII and NIV; setae originate
dorsally rather than ventrally on the proximal endopodal segment. These
unique changes are reversed during the molt to NVI.
Conclusions: Many of these changes
have not been reported for any other calanoid. The morphological
restoration at NVI is particularly noteworthy.
Key words: Naupliar development; Pseudocyclops sp; Calanoida; Shedd
aquarium.
*Correspondence: E-mail: hansdahms@smu.ac.kr
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