Megalomma perkinsi Tovar-Hernández and Salazar-Vallejo, 2006

Tovar-Hernández, María Ana & Carrera-Parra, Luis F., 2011, Megalomma Johansson, 1925 (Polychaeta: Sabellidae) from America and other world-wide localities, and phylogenetic relationships within the genus 2861, Zootaxa 2861 (1), pp. 1-71 : 47-48

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.

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.

Figures

FIGURE 11. Megalomma fauchaldi Giangrande et al. 2007. A) Thorax, dorsal view; B) same, lateral view; C) same, ventral view; D) dorsalmost radiolar eye; E–G) eyes from lateral radioles. A–G) Specimen from Galeta Reef, Panama, USNM, 066403. Abbreviations: dlc dorsal lappets. Scale bars: A–C) 0.5 mm, D–G) 0.3 mm.

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.