Megalomma Johansson, 1925 (Polychaeta: Sabellidae) from America and other world-wide localities, and phylogenetic relationships within the genus 2861
Author
Tovar-Hernández, María Ana
Author
Carrera-Parra, Luis F.
text
Zootaxa
2011
2011-04-29
2861
1
1
71
https://biotaxa.org/Zootaxa/article/view/zootaxa.2861.1.1
journal article
10.11646/zootaxa.2861.1.1
11755334
5286352
Megalomma perkinsi
Tovar-Hernández and Salazar-Vallejo, 2006
Figure 21A–G
Megalomma perkinsi
Tovar-Hernández and Salazar-Vallejo, 2006: 43–45
,
Fig. 11
.
Type material examined.
[
USNM
]
53976, Acc. No. 305023,
holotype
of
Megalomma perkinsi
, previously labeled as
M. lobiferum
(Ehlers)
and then as
M
. sp A Perkins, Cape Lookout,
North Carolina
,
April 16, 1976
, Coll. S. L. Gardiner, intertidal, sand mixed with gravel and shell fragments, 129.
FIGURE 21
.
Megalomma perkinsi
Tovar-Hernández and Salazar-Vallejo, 2006
. A) Thorax, dorsal view; B) same, lateral view; C) same, ventral view; D) dorsal lips; E) dorsalmost radiolar eye; F) eye from a lateral radiole; G) eye from a ventral radiole. A–G) Holotype from North Carolina, USNM, 53976. Abbreviations:
dl
dorsal lip;
vl
ventral lip. Scale bars: A–C) 1 mm; D) 0.5 mm; E–G) 0.3 mm.
Additional material examined.
[
USNM
]
108232,
North Carolina
,
33° 48’ 30’’ N
,
76° 34’ 12’’ W
,
Coll. Duke University
for
MMS
/BLM,
Vessel Eastward
R
/
V
, 144.5 m (
1 spec.
)
.
Florida
, 090412, off
St Petersburg
,
27° 56’ 30’’ N
,
83° 53’ 00 W
,
July 1976
,
Sta.
11–2211, 43 m
,
MAFLA
,
Acc.
332151 (
1 spec.
)
.
090411,
24° 47’ 07’’ N
,
83° 13’ 05’’ W
,
August 1981
,
Sta.
28,
SOFLA
,
58 m
(
1 spec.
)
.
090413,
29° 24’ 00’’ N
,
85° 42’ 02’’ W
,
August 1977
,
Sta.
2854,
MAFLA
,
4 m
(
1 spec.
)
.
098226,
Looe Key National Marine Sanctuary
,
24° 33’ N
,
81° 21’ W
,
Coll. Thomas J
,
October
1983
, 1 m (
1 spec.
)
.
45692,
Tampa Bay
,
Coll. Taylor, J. L.
, 1963 (
1 spec.
)
.
45692,
Tampa Bay
,
Coll. Taylor, J. L.
, 1963 (
1 spec.
)
.
Panama
, STRI
Panama
survey,
Sta.
133–2,
April 5, 1973
,
Acc. No.
292528 (
1 spec.
)
.
Diagnosis.
Eyes in most radioles (oval and spherical); dorsal margins of collar fused to faecal groove; keel present; dorsal pockets and dorsal lappets present; thoracic chaetae
Type
A.
Description.
Branchial crown longer than thorax with 22 (23) pairs of radioles. Branchial crown with three purplish-brown bands on first half of crown. Outer surfaces of radioles quadrangular basally, rounded distally. Subdistal compound eyes present in most radioles. Dorsalmost pair of radioles with eyes distinctly larger, oval, radiolar tips short (
Fig. 21E
). Lateral and ventral radioles with spherical eyes, distinctly smaller than dorsal ones, radiolar tips longer gradually towards ventral radioles (
Fig. 21F–G
). Dorsal collar margins fused to faecal groove (
Fig. 21A
). Dorsal lappets rounded, longer than lateral collar margins (
Fig. 21A
). Dorsal pockets well developed, Ushaped (
Fig. 21A
). Ventral lappets rounded, not overlapping (
Fig. 21C
), as long as ventral shield of collar. Anterior peristomial ring not exposed beyond collar. Lateral collar margins not covering the basal union of radioles (
Fig. 21B
). Dorsal lips with orange pigment laterally, erect, triangular, very long (about ¼ of branchial crown length), with mid-rib (
Fig. 21D
). Dorsal pinnular appendages present. Ventral lips about half as long as dorsal lips, broadly rounded. Ventral sacs present. Caruncle absent. Keel present. Body depressed. Total thorax-abdomen length
107 mm
(92). Seven thoracic chaetigers. Thoracic tori of similar length in all segments. Tori in chaetigers 2–3 short, occupying a half of the distance between notopodia and ventral shield margins (
Fig. 21C
), not contacting shields. Inferior thoracic chaetae
Type
A. Thoracic uncini with crest surmounted by 7–9 rows of numerous minute teeth, handles 2x length of main fang. Companion chaetae with teardrop-shaped membranes. Abdomen with 66–122 chaetigers. Abdominal chaetae unknown. Abdominal uncini with main fang surmounted by 8–10 rows of numerous minute teeth. Pygidium rounded. Tubes covered with shell fragments.
Remarks.
Original description of
M. perkinsi
by
Tovar-Hernández and Salazar-Vallejo (2006)
state that compound radiolar eyes are flat; however, eyes from dorsalmost radioles are oval and flat lightly in
holotype
while other radioles have spherical eyes (based on re-examination). Also, the original description provided by Tovar- Hernández and Salazar-Vallejo (2006) contains other mistake: middorsal collar margins are fused to faecal groove but not “not-fused” as originally described. These misinterpretations were corrected in the above redescription and scored in the phylogenetic analysis.
Megalomma perkinsi
,
M. acrophthalmos
,
M. fauchaldi
,
M. lanigera
,
M.
sp., and
M. nechamae
have dorsal lappets rounded, longer than lateral collar margins.
Megalomma acrophthalmos
and
M.
sp., have caruncle (absent in
M. perkinsi
,
M. fauchaldi
,
M. lanigera
and
M. nechamae
).
Megalomma perkinsi
have dorsalmost radioles with oval eyes while in
M. fauchaldi
,
M. lanigera
and
M. nechamae
these are spherical.