Amaeana sp. 1

Londoño-Mesa, Mario H., 2009, Terebellidae (Polychaeta: Terebellida) from the Grand Caribbean region 2320, Zootaxa 2320 (1), pp. 1-93 : 11-13

publication ID	https://doi.org/ 10.11646/zootaxa.2320.1.1
persistent identifier	https://treatment.plazi.org/id/03F75303-AE54-FFB2-FF7E-FBB13C3081B3
treatment provided by	Felipe
scientific name	Amaeana sp. 1
status

Treatment

Amaeana sp. 1

Figures 2 View FIGURE 2 A-J

Amaeana trilobata, Kritzler, 1984:52–27 View in CoL ; Figs 52–21, 22A-E.

Material examined: Gulf of Mexico : USNM 90555 About USNM (1), 90556 (1) South Timbalier Lease Area, Louisiana (28°40'02"N 90°14'43"W), 28.V.1978; 32m. GoogleMaps USNM 56036 About USNM (2) R/ V Columbus Iselin, id. P.G. Johnson (no more data). Antilles: USNM 81866 About USNM (1) Off Palominos Island , Fajardo, Puerto Rico (18°20'40.5"N 65°34'55"W), VII.1963; 16.6m GoogleMaps .

Description: USNM 90555 complete, fragmented in two, anterior fragment 19 segments, 11mm long, thorax 8.3mm long and 2.3mm wide ( Fig. 2A View FIGURE 2 ). Posterior fragment about 40 segments. Anterior thoracic dorsum with many small tubercles aligned in transverse lines ( Fig. 2B View FIGURE 2 ). Tentacular membrane well developed, with two lateral folds and one middle fold, tentacles emerging near ridge, in two lengths, long, thicker, with swollen tips and short, thinner, with swollen tips. Eyespots absent. Upper lip long, projected forwards ( Figs 2B,C View FIGURE 2 ). Lower lip prominent, membranous, V-shaped in profile, projected ventrally ( Fig. 2D View FIGURE 2 ). Ten ventral shields from segment 3, small and short, inside narrow ventral groove formed by two lateral and longitudinal glandular ridges reaching posterior abdominal segments ( Fig. 2E View FIGURE 2 ), and having many tubercles on surface. Nephridial papillae rounded, with central pore, on segments 4–8, first pair smaller; all papillae placed ventrally to notopodia. Notopodia from segment 2, long and thin, with distal curved chaetal lobe; 12 pairs of thoracic notopodia; thoracic chaetae capillary of one length, long, smooth and finely tipped ( Figs 2F,G View FIGURE 2 ). Segment 13– 19 achaetigerous, then, abdomen with at least 17 segments with neurochaetae from segment 20; abdominal neurochaetae spine-like, straight, acute, thicker than thoracic notochaetae ( Figs 2H,I View FIGURE 2 ). Pygidium smooth, with ridge slightly swollen ( Fig. 1J View FIGURE 1 ).

Staining pattern: Nephridial papillae stain deeply. Lower lip, ventral shields, dorsal tubercles and ventral ridges in anterior thoracic segments stain less intensely. Remaining structures do not stain significantly.

Variations: All additional specimens incomplete, 6.7–13.5mm long, thorax 4.2–6.5mm long and 1.5– 2mm wide. Specimen USNM 81866 has 10 pairs of notopodia and USNM 90556 has 11 pairs of notopodia. Specimens USNM 56036 are incomplete anteriorly. Thoracic chaetae of additional specimens seem to be longer (more emergent). No variation in the pygidium is reported since there is only one complete specimen.

Discussion: These specimens are similar to Amaeana trilobata ( Sars, 1863) , from Norway, and reported by Holthe (1986b). He states that the tentacular membrane has two lateral lobes, and one median lobe formed by the lower lip; ten thoracic segments with notochaetae; 5–6 achaetigerous segments after the last thoracic notopodium; abdominal neuropodia with straight spine-like neurochaeta. A. trilobata differs mainly because it has thoracic notochaetae finely denticulate and 10 nephridial papillae from segment 3. Holthe’s illustration of the spines (erroneusly referred as acicula by him) is almost the same as those presented by the present specimens. A. trilobata is also described by Fauvel (1927) and Day (1967); they described nephridial papillae on all thoracic segments with chaetae, thoracic notochaetae slightly bilimbate and abdominal spines somewhat curved distally. Thus, the present material has 5 pairs of nephridial papillae on segments 4–8, capillary notochaetae alimbate, and spine-like neurochaetae completely straight, clearly differing from A. trilobata . Nevertheless, some confusion is present in the description of A. trilobata by these authors; for example, the type of thoracic notochaetae (denticulate or bilimbate) and shape of spines (straight or distally curved), which indicate the necessity for revising and comparing with type specimens or material from the type locality.

The specimen described above presents median and posterior thoracic dorsum with large sacs formed by epicuticule dilatations. Variation in length of the thoracic chaetae presented by additional specimens, could be due to the form of the notopodial lobe, which may cover the base of the chaetae, giving the impression of shorter chaetae. This situation was refered by Kritzler (1984) as retractile notochaetae, although this could be due to the way the material was fixed. Since notopodia are highly extensile, chaetae can be retracted or extended. This author also mentions the presence of limbate and penicillate thoracic notochaeta; nonetheless, re-examination of his material, revealed the absence of penicillate notochaeta. Revision of all the specimens is required in order to elucidate if there is one or more species involved.

Distribution: Louisiana (Gulf of Mexico), Puerto Rico.