Errinopora
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Ordo: Filifera
Familia: Stylasteridae
Name
Errinopora Fisher, 1931 – Wikispecies link – Pensoft Profile
- Errinopora Fisher, 1931: 397; 1938[1]: 536.—Boschma 1956[2]: F102; 1957[3]: 57.—Cairns 1983a[4]: 123; 1983b[5]: 462. —Lindner 2005[6]: 79-88.
- Protoerrina Broch, 1935: 59; 1936[7]: 99-100.
Diagnosis
(emended from Lindner 2005[5]): Colonies uniplanar to slightly bushy; branches round, elliptical, or lamellar in cross section, often robust with blunt tips. Coenosteal texture reticulate-spinose (with wide slits resulting in a spongy texture) or reticulate-granular; exterior surface of dactylopore spines usually inconspicuously longitudinally ridged; coenosteum orange, pink, and white. One species, Errinopora cestoporina, bears numerous perforated mounds on surface. Dactylopores dimorphic, the most common, termed the primary dactylopore spine, is U-shaped and usually robust (thick-walled), occurring randomly, in pseudocyclosystems, or often laterally fusing to form rows or taller terraces that flank rows of gastropores. When dactylopore spines flank both sides of a gastropore row and their dactylotomes are directed toward the gastropores it is termed bilateral or distichoporine; if only one row of spines flank a row of gastropores, then unilateral. If isolated, dactylotomes usually abcauline in orientation. Much smaller flush dactylopores, termed secondary dactylopores, which lack dactylostyles, commonly scattered over coenosteum of many species. Dactylostyles usually well developed, easily seen from external view. Secondary dactylopores much smaller, flush with coenosteum, and lack styles. Gastropores also dimorphic, the primary gastropores being circular in outline, flush with coenosteum (having no lip), and arranged in irregular vertical rows, short horizontal rows, or randomly. Tabulae and ring palisades absent. Gastrostyles lanceolate, covered with longitudinal or oblique, spiny ridges. Smaller secondary gastropores much smaller, having only a small gastrostyle or none at all. Female ampullae superficial hemispheres, often without an obvious efferent pore. Male ampullae usually smaller hemispheres and spongy.
Discussion
The ten species in this genus are differentiated and compared in both a dichotomous key (see below) and tabular key (Table 1); six of them occur exclusively in the Aleutian Islands. Another species was tentatively assigned to this genus by Cairns (1983b)[5], Errinopora lobata (Nielsen, 1919), a Paleocene fossil from Denmark. This species was re-examined by Bernecker and Weidlich (1990[8], 2005[9]), based on subsequently collected non-type material from the Faske Formation in Denmark. They noted that whereas the dactylopore spines were typical of Errina or Errinopora, the spines did not contain dactylostyles, and thus resembled Errina more than Errinopora. We have examined the holotype of Labiopora lobata Nielsen, 1919 (GM1782), which is a uniplanar colony 10.2 cm tall and 8.0 cm wide, with branches about 0.5 cm in diameter embedded within a Dendrophyllia matrix. The colony has pores, or broken bulges, of three sizes: small and elongate (75–110 µm in width), medium and round to somewhat quadratic (0.3–0.53 mm wide), and large, round or somewhat triangular (up to 1.7 mm). The former are quite shallow and probably the result of a reticulate coenosteal surface, whereas the medium-sized pores are deep and possibly represent the gastropores, one of which has a cyclosystem-like structure 1.9 mm in diameter. The largest pores appear to be ruptured ampullae. None of them, however, resemble dactylopore spines like those reported by Nielsen (1919) or Bernecker and Weidlich (1990[8], 2005[9]), suggesting that the species reported by the latter authors is neither Errina nor Errinopora. Likewise, the lack of dactylopore spines in the type of Labiopora lobata precludes it from being Errinopora, and thus we currently suggest an incertae sedis placement of this species until further analysis.
Species within Errinopora are unique with the Stylasteridae in having both dimorphic gastro- and dactylopores, a condition first noted by Fisher (1938)[1] for three Alaskan species but interpreted exclusively as secondary dactylopores. Careful examination of longitudinal sections of several of these pores reveal that they contain not dactylostyles, but rather small gastrostyles. This implies that most species of Errinopora (all but Errinopora fisheri and Errinopora cestoporina Cairns, 1983, see Table 1) have two types of gastrozooids (feeding polyps), a unique case for stylasterids but previously reported for the hydractiniids Stylactaria conchicola (see Namikawa et al. 1992[10]). Secondary gastropores differ from primary gastropores in being narrower and deeper, and in having only a minute or no gastrostyle. All but one species (Errinopora fisheri, see Table 1) also have dimorphic dactylopores: a large type surrounded by a prominent horseshoe-shaped spine, and smaller, flush pores only 40–110 µm in diameter, which do not have dactylostyles and are termed secondary dactylopores.
In comparison to other stylasterid genera, Errinopora is most similar to Gyropora Boschma, 1960, whose only species, Gyropora africana Boschma, 1960, has dactylopore spines and gastropores coordinated in pore rows, as in some species of Errinopora. Errinopora is also similar to Errina Gray, 1835 and Errinopsis Broch, 1935, whose species may also have thick-walled dactylopore spines. None of these genera, however, include species with dactylostyles, as in Errinopora. Among genera with species having dactylostyles, only species of Errinopora, Inferiolabiata Broch, 1951, and Paraerrina Broch, 1942 lack a coordination of gastropores and dactylopores in well-developed cyclosystems (whereas species of Stenohelia Kent, 1870, Stylantheca Fisher, 1931, Stylaster Gray, 1831 and Calyptopora Boschma, 1968 do have both dactylostyles and well-developed cyclosystems). Inferiolabiata differs from Errinopora in many characters, in particular by having thin-walled dactylopore spines (instead of thick-walled) that are markedly truncated at the tip (instead of rounded), whereas Paraerrina Broch, 1942 differs in having delicate dactylostyles (instead of robust) and either flush or only slightly raised dactylopore spines—instead of tall and robust (Cairns 1984, 1991[11]). Errinopora is also one of the few stylasterid genera with species having calcitic, rather than aragonitic, colonies (Thompson and Chow 1955[12], Lowenstam 1964[13], Cairns and Macintrye 1992[14]). The only other stylasterid genera with species known to have mostly calcitic colonies are Errinopsis, Errina, and one species of Stylaster—Stylaster verrillii (Dall, 1884) (see Cairns and Macintrye 1992[14]). Within Errinopora, only Errinopora cestoporina, known solely from the Subantarctic Region, is known to have coralla formed by precipitation of aragonite. This result confirms the more general observation of the prevalence of calcitic stylasterids in the North Pacific (Cairns and Macintrye 1992[14]), possibly related to the shallower depth of the Aragonite Saturation Horizon (ASH) in the Region (Guinotte et al. 2006).
In an attempt to investigate phylogenetic relationships, 37 partial mitochondrial rDNA 16S sequences were obtained for the six species of Errinopora from the Aleutian Islands, including the holotypes of Errinopora dichotoma, Errinopora disticha, Errinopora fisheri and Errinopora undulata. Based on Lindner et al. (2008)[15] included Errinopora nanneca (specimen USNM1027820) and Errinopora zarhyncha Fisher, 1938 (specimen USNM1071915), and shows that these species diverged only about 4 million years ago. Moreover, the same study shows that Cyclohelia lamellata Cairns, 1991 and Distichopora borealis Fisher, 1938, two sympatric Alaskan stylasterids that are also clearly distinguishable with marked morphological differences (see above), may have diverged as recently as 1 million years ago. These results indicate that part of stylasterid species diversity in Alaska may have diverged only within the past 1-4 million years and, at least for Errinopora, the results presented herein show that despite the marked morphological differences, some species are not recovered as reciprocally monophyletic lineages (Baum and Shaw 1995[16], Avise 2000[17]) using mitochondrial rDNA 16S.
Type species
Errina pourtalesii Dall, 1884, by original designation.
Distribution
North Pacific: Aleutian Islands, Kurile Islands, Sea of Okhotsk, Sea of Japan, off California. Subantarctic: off Tierra del Fuego, 40–658 m. {| class="wikitable" ; style="width: 100%" |+ Table 1. Tabular Key of the Ten Species of Errinopora (pscs = pseudocyclsosystems) |- ! !! iErrinopora fisher !! aErrinopora cestoporin !! aErrinopora porifer !! aErrinopora undulat !! aErrinopora distich !! iErrinopora pourtalesi !! aErrinopora stylifer !! aErrinopora zarhynch !! aErrinopora nannec !! aErrinopora dichotom |- ! Dactylopore Spines !! !! !! !! !! !! !! !! !! !! |- | Arrangement || Tall terraces and pscs || Tall terraces and pscs || Isolated or short unilateral rows || Pscs and short unilateral rows || Distichoporine rows; pscs at base || Distichoporine rows, unilateral rows, isolated, pscs || Distichoporine rows, pscs at base || Short unilateral rows, isolated || Short unilateral rows, pscs, isolated || Short unilateral rows, isolated |- | Compound Dactylopore Spines || Absent || Absent || Absent || Absent || Present || Present || Absent || Present || Absent || Present |- | Maximum Height || 1.5 mm || 1.3 mm || 0.46 mm || 0.25 mm || 0.5–0.9 mm || 1.1–1.2 mm || 0.5–0.9 mm || to 3 mm || 0.4 mm || 1.2 mm |- | Wall Thickness || Not individualized || Thick || Thin || Thin || Thick || Thick || Thick || Thick || Thick || Thick |- | Dactylotome Shape || Elliptical pores || Slit || Apical pores || Slit || Slit || Slit || Slit || Slit || Slit || Slit |- | External Surface of Dactylopore Spine || Inconspicuously ridged || Reticulate-Granular || Not ridged || Inconspicuosly ridged || Inconspicuously ridged || Inconspicuously ridged || Inconspicuously ridged || Inconspicuously ridged || Prominently ridged || Inconspicuously ridged |- | Dactylostyle || Narrow || Robust || Moderate width || Robust || Robust || Robust || Robust || Narrow || Moderate width || Robust |- | Secondary Dactylopores || Absent || Present || Present || Present || Present || Present || Present || Present || Present || Present |- | Corallum || || || || || || || || || || |- | Shape || Uniplanar || Bushy || Uniplanar || Lamellate || Uniplanar || Bushy || Uniplanar || Uniplanar || Uniplanar branching or plate-like || Three dimensional |- | Branch Size || Delicate || Delicate || Delicate || Sheets thin || Robust || Medium || Medium || Large || Delicate || Robust |- | Branch Cross Section || Circular to elliptical || Circular || Circular to slightly elliptical || Lamellar || Flattened || Circular || Circular to slightly elliptical || Circular to elliptical || Circular to lamellar || Circular to slightly elliptical |- | Color || Orange || White || White, light orange || Orange || Light orange || Orange || Orange, yellow || Orange || Orange, pink || Orange |- | Other Characters || || || || || || || || || || |- | Gastropore Diameter || 0.3–0.5 mm || 0.30–0.55 mm || 0.23–0.27 mm || 0.30–0.45 mm || 0.3–0.7 mm || 0.20–0.38 mm || 0.4 mm || 0.2–1.1 mm || about 0.2 mm || 0.3–0.5 mm |- | Secondary Gastropores || Absent || Absent || Present || Present || Present || Present || Present || Present || Present || Present |- | Coenosteal Texture || Reticulate-Spinose || Reticulate-Granular || Reticulate-Granular || Reticulate-Spinose || Reticulate-Spinose || Reticulate-Granular || Reticulate-Granular || Reticulate-Spinose || Reticulate-Spinose || Reticulate-Spinose |- | Unique Features || Gastropore tube constricted; ring palisade present; gastrostyles squat || Conical ampullae; coenenchymal papillae; gastrostyle pedicellate || Dactylopore spines conical || || Gastrostyles flattened in cross section || Encrusting base || || Gastropore tubes commodious || || U-shaped branching axils |- | Distributon and Depth Range || Aleutian Islands, 455 m || Tierra del Fuego, 359–384 m || Okhotsk Sea, 190–250 m || Aleutian Islands, 350–640 m || Aleutian Islands, 178–536 m || Central California,49–183 m || Off Japan, Okhotsk Sea, 84–379 m || Aleutian Islands,207–658 m || Aleutian Islands,40–517 m || Aleutian Islands,178–217 m |}
Key to the Recent species of Errinopora (bold face = occurs off Alaska)
Taxon Treatment
- Cairns, S; Lindner, A; 2011: A Revision of the Stylasteridae (Cnidaria, Hydrozoa, Filifera) from Alaska and Adjacent Waters ZooKeys, 158: 1-88. doi
Other References
- ↑ 1.0 1.1 Fisher W (1938) Hydrocorals of the North Pacific Ocean. Proceedings of the United States National Museum 84 (3024): 493-554. doi: 10.5479/si.00963801.84-3024.493
- ↑ Boschma H (1956) Milleporina and Stylasterina. In: Moore RC (Ed) Treatise on Invertebrate Paleontology, Part F, University of Kansas Press, Lawrence, Kansas, F90-F106.
- ↑ Boschma H (1957) List of the described species of the order Stylasterina. Zoologische Verhandelingen 33: 1-72.
- ↑ Cairns S (1983a) Antarctic and Subantarctic Stylasterina (Coelenterata: Hydrozoa). Antarctic Research Series 38: 61-163. doi: 10.1029/AR038p0061
- ↑ 5.0 5.1 5.2 Cairns S (1983b) A generic revision of the Stylasterina (Coelenterata: Hydrozoa). Part 1. Description of the genera. Bulletin of Marine Science 33 (2): 427-508.
- ↑ Lindner A (2005) Evolution and Taxonomy of Stylasterid Corals (Cnidaria: Hydrozoa: Stylasteridae). PhD thesis, Chapel Hill, North Carolina, Duke University, 165 pp.
- ↑ Broch H (1936) Untersuchungen an Stylasteriden (Hydrokorallen). Teil 1. Skrifter utgitt av Norske Videnskaps-Akademi i Oslo. 1. Matematisk-Naturvidenskapelig Klasse 8: 1-103.
- ↑ 8.0 8.1 Bernecker M, Weidlich O (1990) The Danian (Paleocene) coral limestone of Fakse, Denmark: a model for ancient aphotic, azooxanthellate coral mounds. Facies 22: 103-138. doi: 10.1007/BF02536947
- ↑ 9.0 9.1 Bernecker M, Weidlich O (2005) Azooxanthellate corals in the Late Maastrictian – Early Paleocene of the Danish basin: bryozoan and coral mounds in a boreal shelf setting. In: Freiwald A Roberts J (Eds). Cold-water Corals and Ecosystems. Springer-Verlag, Berlin: 3-25. doi: 10.1007/3-540-27673-4_1
- ↑ Namikawa H, Mawatari S (1992) Role of the tentaculozooids of the polymorphic hydroid Stylactaria conchicola (Yamada) in interactions with some epifaunal space competitors. Journal of Experimental Marine Biology 62: 65-75. doi: 10.1016/0022-0981(92)90125-T
- ↑ Cairns S (1991) Cyclohelia lamellata, new genus and species of Stylasteridae (Cnidaria: Hydrozoa) from the Bering Sea. Pacific Science 45 (4): 383-388.
- ↑ Thompson T, Chow T (1955) The strontium-calcium atom ratio in carbonate-secreting marine organisms. Deep-Sea Research (Supplement) 3: 20-39.
- ↑ Lowenstam H (1964) Coexisting calcites and aragonites from skeletal carbonates of marine organisms and their strontium and magnesium contents. In: Miyake Y Koyama T (Eds). Recent Researches in the Fields of Hydrosphere, Atmosphere, and Nuclear Geochemistry, Maruzen C. , Ltd, Tokyo: 373-403.
- ↑ 14.0 14.1 14.2 Cairns S, Macintrye I (1992) Phylogenetic implications of the calcium carbonate mineralogy in the Stylasteridae (Cnidaria: Hydrozoa). Palaios 7: 96-107. doi: 10.2307/3514799
- ↑ Lindner A, Cairns S, Cunningham C (2008) From offshore to onshore: multiple origins of shallow-water corals from deep-sea ancestors. PLoS One 3(6): e2429. doi:10.1371/journal.pone.0002429
- ↑ Baum D, Shaw K (1995) Genealogical perspectives on the species problem. In: Hoch P Stephenson A (Eds). Experimental and Molecular Approaches to Plant Biosystematics, Missouri Botanical Garden, St. Louis: 289-303.
- ↑ Avise J (2000) Phylogeography: the history and formation of species, second edition. Harvard University Press, Cambridge, 447 pp.
