A Review of the Genus Eunice - Smithsonian Institution Libraries

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SMITHSONIAN CONTRIBUTIONS TO ZOOLOGY
simple hooks present in a few anterior setigers; eunicids have
compound hooks present in all segments (except in Eunice
afuerensis and E. pelamidis). Further, the hooks appear very
different and no structural analysis has been done to demonstrate
their homologies.
For this reason, a second outgroup was selected. In this case
a eunicid, Marphysa sanguinea (Montagu, 1815), was selected
as an outgroup; this species is a member of the genus that most
closely resembles Eunice. Marphysa sanguinea has been
reported widely from warm-water areas and the identity of the
different populations is problematic. For that reason, a single
specimen from Florida (USNM 17131) was examined when the
descriptions of the species were too vague to be used in the
analysis, or when features had not been included in previous
descriptions. As mentioned above, the presence of peristomial
cirri is a distinct synapomorphy for all species of Eunice in
relation to M. sanguinea (or alternatively the absence of
peristomial cirri in Marphysa may represent an apomorphy for
that genus; this issue will be explored at a later date).
CHARACTER LIST
Originally a character list including, in all, 228 characters
was developed. The standardized format used in character files
of DELTA, a program for developing standardized keys and
descriptions, was originally used to develop the list. The list
was based on the first 50 species encountered in an alphabetic
listing of the species. The character states were systematically
organized from small to large (few to many) and from absent to
present. Additional character states were included as encountered
going through the remaining descriptions. Once an
outgroup had been selected (see below), the character list was
rescored, using the character state present in the outgroup as the
plesiomorphic condition. Where a character was missing in the
outgroup, the character states were ordered as in the original
list, but were always run as unordered in the analysis.
The original DELTA-style table included some 228 "characters,"
many of which created serious problems in the cladistic
analysis. Iterated reductions in the number of characters,
combining the extremely detailed notations necessary for
descriptions, led to the development of an analyzable character
list. The result was a list (Appendix A) of 68 characters, of
which 38 are multistate and 30 binary. Appendix A also
includes a series of measurements and numerical counts that
were excluded from the analysis, because they could not be
broken down into discrete states. The total number of character
states are 210, barely adequate for the number of taxa present,
if all character states had shown perfect behavior in the
analysis.
Plesio- and Apomorphic States of the Characters
All characters are included in this overview, except those
that identify the specimens, such as species number, name, state
of specimen completeness, and sex. Characters and character
states are those included in the preparation of the key; it is a
printout of the DELTA file CHARS without the formatting
characters. The characters are grouped by major morphological
structures. Character state 1 is always plesiomorphic.
Size Characters
1. number of setigers
2. total length mm
These two characters are mentioned only for complete
specimens. In all other species they have been scored as
unknown. Length is measured from the tip of the prostomium
to the end of the pygidium; antennae and anal cirri are omitted.
3. maximum width in mm
4. maximum width first reached at sctigcr
5. length through setiger 10 in mm
6. width at sctigcr 10 in mm
These characters can be scored for all specimens. The
combined score of characters 3, 4, and 6 can be used to
characterize the overall shape of the body. Character 5 can give
a good approximate measure of total size of incomplete
specimens (Fauchald, 1991).
Prostomium and Peristomium
7. prostomium
1. frontal ly truncate
2. frontally obliquely truncate
3. frontally rounded
8. prostomium
1. dorsally inflated
2. dorsally flattened
3. dorsally excavate with a thickened rim
9. median sulcus
1. median sulcus invisible dorsally
2. median sulcus shallow
3. median sulcus deep
These characters define the shape of the prostomium. They are
observed from the dorsal and lateral side. For characters 7 and
8, both outgroup species have character state 1. Kinbergonuphis
simoni lacks a median sulcus wholly; Marphysa
sanguinea has a shallow, rather wide notch.
10. prostomium
1. distinctly shorter than peristomium
2. about as long as peristomium
11. prostomium
1. about as wide as peristomium
2. distinctly narrower than peristomium
12. prostomium
1. less than x li as deep as peristomium
2. as deep as x li of the peristomium or deeper
These characters define the size of the prostomium in relation
to the rest of the anterior end. By "distinctly shorter" in
character 10 is meant "more than 30% shorter than"; the
break-off point is defined similarly for characters 11 and 12.