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Comprehensive Description

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Description

5. Ainigmaptilon Dean, 1926

 

FIGURE 4H–P

 

Ainigmaptilon Dean, 1926:337.—Carlgren, 1943:1–7.—Bayer, 1950:295–296 [key to species]; 1956:F222; 1981b:936 [key to genus].—Bayer and Stefani, 1989:455 [key to genus].—Bayer, 1996b:151.

 

Lycurus Molander, 1929:66–70.

 

DIAGNOSIS. Colonies unbranched (flagelliform), the stem terminating proximally in a funnel-shaped base, which, when filled with mud, functions as an anchor in soft sediment. Calyces arranged in terminal clusters of up to 30 on unsupported, simple, or branched fleshy lobes, called polyp leaves (Figure 4o, p) by previous authors. Polyp leaves arranged in an alternate biserially manner on the branch. Well-developed operculum present, each opercular having an extremely long, smooth apical spine (Figure 4h–j), so long that they cannot close over the tentacles of the polyp; inner face of operculars not keeled. Eight marginal scales present but not differentiated from other body wall scales, the latter arranged randomly (type species) or in eight longitudinal rows (e.g., A. edisto). Body wall scales irregular in shape or triangular shaped, with a broad, notched distal end (arrowhead shaped; Figure 4m–n), having a spiny or smooth outer surface. Coenenchymal plates on branch surface as well as leaf surface fusiform in shape, having an L:W of up to 10; outer surface smooth, inner surface tuberculate; no inner layer of specialized coenenchymal sclerites.

 

DISCUSSION. Ainigmaptilon has such an unusual mixture of characters that Dean (1926:337) remarked that it “differs so extraordinarily from any other Alcyonarian so far described that one finds it difficult to assign it to even any of the five large orders.” She was referring not only to the leaf-like arrangement of the polyps and axial canal structure, which allied it to the order Pennatulacea, but also to the scale-like sclerites and lack of siphonozooids, which allied it more to the family Primnoidae of the order Gorgonacea. She finally provisionally placed the new genus in the pennatulacean, with affinities to the Virgulariidae. Perhaps unaware of Dean’s work, Molander (1929) described two new species with similar morphology, but after going through much the same soul-searching as Dean, he concluded that his two species belonged in a new primnoid genus (Lycurus) and new subfamily (Lycurinae), having affinities to the primnoid Callozostron. Hickson (1930) also favored a placement of Ainigmaptilon as a primnoid, but Thomson and Rennet (1931) reverted to Dean’s logic in placing it as a pennatulacean genus “Incertae sedis.” Carlgren (1943) described yet a fourth species, synonymized Ainigmaptilon and Lycurus, and raised Molander’s subfamily to family rank: Ainigmaptilonidae, with suggested affinities to the Primnoidae. Bayer (1950) described the fifth species (Table 4) and maintained the taxon as a separate family (but corrected the spelling of the family name to Ainigmaptilidae), as he (Bayer, 1956) did in the Treatise revision; however, in Bayer (1981b) and subsequent papers (see synonymy above), without explanation he considered Ainigmaptilon as a genus in the Primnoidae. Bayer (1996b) compared Ainigmaptilon to Callozostron, summarized in the discussion of the latter genus herein.

 

The crystal orientation of the scales of Ainigmaptilon edisto is radial, producing the characteristic primnoid cruciform extinction pattern under crossed Nicols. The position of polyps on a leaf-like structure and the funnelshaped base are unique characters for this genus.

 

Distribution. Antarctica to South Georgia, 75–550 m.

 

Type Species. Ainigmaptilon: A. haswelli Dean, 1926, by monotypy. Type reputed to be deposited at the University Museum, Sydney. The type species is best described by Dean (1926); Thomson and Rennet (1931) inexplicably repeated her description with virtually no changes, using Dean’s figures as well.

 

Lycurus: L. virgularoides Molander, 1929, here designated. The type is reputedly deposited at the Stockholm Museum of Natural History.

 

Bayer and Cairns, 2009

 

Dean, 1926

 

Carlgren, 1943

 

Bayer, 1950

 

Bayer, 1981b

 

Bayer and Stefani, 1989

 

Bayer, 1996b

 

Molander, 1929

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Creative Commons Attribution Non Commercial 3.0 (CC BY-NC 3.0)

© National Museum of Natural History, Smithsonian Institution

Source: Antarctic Invertebrates Website (NMNH)

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