Research Article |
Corresponding author: Gary Williams ( gwilliams@calacademy.org ) Academic editor: Leen van Ofwegen
© 2015 Gary Williams.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Williams GC (2015) A new genus and species of pennatulacean octocoral from equatorial West Africa (Cnidaria, Anthozoa, Virgulariidae). ZooKeys 546: 39-50. https://doi.org/10.3897/zookeys.546.6344
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A new genus and species of sea pen or virgulariid pennatulacean from the Gulf of Guinea in the tropical eastern Atlantic is described, and a key to the genera of the Virgulariidae is included. The new genus and species described here adds to the previously described five other genera of the family. It is distinguished by unique sclerite and polyp leaf characters from the superficially-similar genus Virgularia, which lacks conspicuous sclerites in the polyp leaves and coenenchyme (other than minute oval bodies that are generally <0.01 mm in length).
Pennatulacea , Virgulariidae , sea pens, new genus and species, Gulf of Guinea, West Africa, Nigeria, key to the virgulariid genera
The biogeographic region of the Mediterranean Sea and Atlantic coast of Africa is home to several apparently endemic octocoral genera, including the pennatulaceans Amphibelemnon López-González, Gili & Williams, 2000 and Crassophyllum Tixier-Durivault, 1961 (
Five genera were previously included in the family Virgulariidae (Williams, 1995: 122–125) – Acanthoptilum Kölliker, 1870; Scytaliopsis Gravier, 1906; Scytalium Herklots, 1858; Stylatula Verrill, 1864; and Virgularia Lamarck, 1816. The new genus described here adds an additional genus. Consequently, a total of six genera are here recognized as comprising the family Virgulariidae.
Virgulariid sea pens are known to range from intertidal habitats to approximately 1200 m in depth (
It is the aim of this paper to describe a new genus and species of pennatulacean octocoral previously unknown to science, to name the new genus in recognition of the significant career contributions of a prominent octocoral systematist, and to differentiate the new genus from all other genera in the family based on morphological comparisons.
Material for this study was revealed during a survey of the pennatulacean octocoral collection at the
Scanning electron micrographs were made in the Academy’s SEM laboratory with a LEO 1450 VP scanning electron microscope after coating the sclerites on a standard SEM pin stub mount (12.7 mm in diameter and 8 mm pin height) with gold/palladium.
CASIZ
Virgulariid pennatulaceans with polyp leaves rolled or convoluted; 20-26 polyps per polyp leaf; polyp leaves and coenenchyme contain rod-like, somewhat three-flanged sclerites, with parallel sides, broadly triangular at each end, 0.02 to 0.06 mm in length.
Grasshoffia virgularioides by original designation.
The genus is named for Dr. Manfred Grasshoff in recognition of his important contributions to the systematics of octocorals, particularly gorgonians and pennatulaceans. He is currently Honorary Scientist at the Senckenberg Research Institute and Natural History Museum, Frankfurt, for his significant contributions to the taxonomy and evolution of octocoral cnidarians. From 1969–2001, Dr. Grasshoff headed the Marine Invertebrates Section at the Institute, where his main research objectives were the taxonomy of octocorals and the evolutionary biology of coelenterates, as well as more general aspects of evolution and phylogeny. From 1972 to 1989 he published several papers on deep-sea pennatulaceans from European and North Atlantic waters (
Virgulariid sea pens superficially resembling some species of Virgularia. Axis circular in transverse section, extending throughout virtually entire colony length. Polyp leaves variously rolled, funnel-shaped, or semicircular in shape with conspicuous, somewhat narrowed basal stalks. Sclerites of polyps leaves and coenenchyme rod-like with parallel sides and mostly deltoid apices, inconspicuously three-flanged. Preserved colony color cream-white in ethanol.
Holotype:
Morphology (Figures
Grasshoffia virgularioides gen. & sp. n. External morphology. A Holotype (
Grasshoffia virgularioides gen. & sp. n. Diagrams of polyp leaves from the holotype. A A single polyp leaf showing convoluted overall shape and numerous, bulbous, retracted polyps with acute apical tips B Dorsal side of the rachis showing congested placement of polyps on sub-circular polyp leaves attached to the rachis by narrow, neck-like stalks C Transverse section of paratype 1 (
Sclerites (Figures
Color (Figure
The specific epithet is derived from the genus Virgularia and the suffix -oidea (likeness of form); in reference to the superficial resemblance of the colonies to some species of the genus Virgularia.
Virgularia and Scytaliopsis do not have sclerites in the rachis or polyp leaves. Scytalium has ovoid plate-like sclerites in the polyp walls and polyp leaves that are not three-flanged. Grasshoffia has prismatically-shaped rod-like sclerites in the polyp leaves and coencenchyme that are indistinctly three-flanged and have broadly-triangular ends. Species of Stylatula have a fan-like armature of large spindles at the base of each polyp leaf, and most species of Acanthoptilum have a cluster of non-aligned spindles at the base of each polyp leaf. Virgularia, Scytalium, Stylatula, and Acanthoptilum generally have flattened polyp leaves that are variously-shaped, while Grasshoffia has strongly curved, rolled, often horseshow-shaped to funnel-shaped polyp leaves. Stylatula macphersoni López-González, Gili & Williams, 2001, has sclerites in the body walls of the autozooids that are similar in shape to coenenchymal sclerites in Grasshoffia virgularioides (
The coenenchyme covering the rachis is extremely thin, and therefore the rachis and axis diameters are virtually equal. The polyp leaves are distinctly rolled or conspicuously curved, perhaps due to contraction in the wet preserved type material, as the appearance of the living colonies is not known. Siphonozooids were not observed in the preserved type material, possibly due to the congested and contracted state of the polyp leaves along the rachis.
The family name “Virgularidae” was first proposed by
The Virgulariidae is here defined as follows (modified from
1 | Sclerites are present in the rachis and polyp leaves | 2 |
– | Sclerites are absent in the rachis and polyp leaves | 5 |
2 | Sclerites of the polyp leaves are conspicuous spindles or needle-like spindles (0.20–1.50 mm in length) | 3 |
– | Sclerites of the polyp leaves are small oval-shaped plates or slightly three-flanged rods (0.02–0.04 mm in length) | 4 |
3 | Needle-like sclerites form a strong fan-shaped armature at the base of each polyp leaf | Stylatula |
– | Spindle-like sclerites form a weak cluster at the bases of the polyp leaves (but not as a fan), or they are scattered in the polyp leaves and autozooids (but not as basal clusters) | Acanthoptilum |
4 | Numerous ovoid plate-like sclerites are present in the rachis and polyps leaves; sclerites red in color | Scytalium |
– | Numerous prismatically-shaped rod-like sclerites, which are indistinctly three-flanged, are present in the polyp leaves and peduncle; sclerites colorless |
Grasshoffia gen. n. (Figs |
5 | The polyps of a single polyp leaf are of equal size; number of polyps per polyp leaf are highly variable (3–100 or more) | Virgularia |
– | The polyps on the inner portion of a single polyp leaf are smaller in size than those of the outer portion of the leaf; polyps per polyp leaf are few (4–7 in number) | Scytaliopsis |
I am grateful to Stephen Cairns, Department of Invertebrate Zoology,