Hornera jeongsangi, Zágoršek & Chae & Min & Seo, 2017
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publication ID |
https://doi.org/ 10.12651/JSR.2017.6.3.232 |
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persistent identifier |
https://treatment.plazi.org/id/03A687DF-2357-D146-FCE8-617E3E02B98D |
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treatment provided by |
Felipe |
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scientific name |
Hornera jeongsangi |
| status |
sp. nov. |
Hornera jeongsangi n. sp. ( Fig. 2 View Fig )
Material examined.
Holotype (MBRBKSP037) Marado Island , collected at depth 20-30 m, 14 Nov. 2010 by J.E. Seo, B.S. Min and H.J. Yang.
Paratype (MBRBKSP038), Udo Island , collected at depth 14-15 m, 15 Mar. 2013 by B.S. Min and H.J. Yang .
Other materials: Marine Bryozoans Resources Bank of Korea ( MBRBK) Collection-specimens from Biyangdo Island and Munseom Island, collected at depth 20-30 m, 25 Sep. 2011 by J.E. Seo, B.S. Min and H.J. Yang .
Diagnosis. Autozooids in three to five longitudinal rows, with five to seven kenozooids opening around aperture. Autozooidal apertures circular, not in fascicles, peristome with 5-9 prominent spiny protrusions. Gonozooid large, deeply immersed, longitudinally oval, with oval ooeciopore facing frontally. Gonozooidal wall around ooeciopore smooth, perforated only by minute pores.
Description.
Colonies erect, branching, up to 30 mm in height, with enlarged proximal portion attached to hard substratum (rock). Secondary calcification slightly developed on proximal part of colony. Branches cylindrical, up to 3 mm thick, numerous, situated close together and budded alternately from central branch ( Fig. 2A View Fig ). Branches divide dichotomously at interval of 1-2 mm, anastomoses not observed. Cross section of branches circular with one autozooidal tube in centre and six to eight around central one.
Apertures of autozooids face outwards away from axis of colony. Autozooid arranged in alternating longitudinal rows, with up to four series at growing tips, increasing slightly distally by lateral division of zooid rows to 5-6 maximally ( Fig. 2C View Fig ). Frontal surface with longitudinal folds and furrows and conspicuous large kenozooids. Five to seven circular to slightly oval small kenozooids situated alongside of each autozooidal tube, forming prominent longitudinal ridges among them ( Fig. 2C View Fig ).
Autozooidal tubes slightly curved laterally from branch axis and having long peristomes with apertures not arranged in rows (fascicles). Peristomes situated on margin of colony usually longer than those situated on central part of branch ( Fig. 2C View Fig ). Apertures bearing numerous, very prominent, spiny protrusions; unequal in size ( Fig. 2E, F View Fig ). Some protrusions about 63 μm long, some much shorter, only about 26 μm long. Number of protrusions per aperture five to nine. Some of protrusions radiate inwards towards orifice centre ( Fig. 2F View Fig ). Protrusions most developed on outer zooids, and a pair of especially long ones often produced by lateral margin of peristome. Autozooids apertures in centre of a branch often having largest spine developed at middle of proximal border of aperture. This suboral spiny protrusion sometimes as long as peristome.
Abfrontal surface of colony formed by longitudinal series of kenozooids and ridges among them ( Fig. 2B View Fig ). Sizes of abfrontal kenozooids vary, but always smaller than those on the frontal side.
Gonozooid globular, quite small, conspicuous, extending width of branch, but usually not exceeding width of branch ( Fig. 2B View Fig ). Gonozooidal calcification rugose, densely perforated by reticulate pores, no regularities (such as ridges or quincuncial arrangement of pores) observed ( Fig. 2B View Fig ). Ooeciopore broadly flared, oval, and situated laterally on edge of chamber, facing frontally, very close to branch margin ( Fig. 2C, F View Fig ). Gonozooidal wall around ooeciopore smooth, perforated only by minute pores ( Fig. 2D, E View Fig ).
Measurements. (in micrometers = μm; () = average) width of branches before bifurcation, 406-480 (458); width of branches after bifurcation, 275-362 (317); length of autozooid, 154-217 (187); width of autozooid, 82-105 (93); diameter of aperture, 55-87 (68); length of frontal kenozooid, 12-27 (20); width of frontal kenozooid, 10-17 (13); length of gonozooid, 1009-1228 (1085); width of gonozooid, 562-1010 (786); length of long spiny protrusions, 53-105 (74); length of short spiny protrusions, 10-17 (12); length of ooeciopore, 122-136 (126); width of ooeciopore, 52-61 (58).
Etymology. The specific name is in honor of Jeong Sang Seo, the founder of Woosuk University.
Remarks. Three other species of Hornera bearing characteristic spiny protrusions on apertures are Hornera pectinata Busk, 1861 , Hornera spinigera Kirkpatrick, 1888 and Hornera pinnata Canu and Bassler, 1929 .
Busk (1861) described Hornera pectinata from Madeira and listed characteristic features such as its small size and the “pectinate” border of the apertures (which according to Busk’s illustrations are best understood as having spiny protrusions around the apertures). His illustrations show a colony with sparsely distributed branches, irregularly arranged apertures with short spiny protrusions, few kenozooids adjacent to autozooidal tubes on the frontal side of the branch, features which distinguish this species from H. jeongsangi n. sp. Moreover, Busk (1861) did not describe or illustrate any gonozooecia so comparison of this important feature is not possible.
Kirkpatrick (1888) described Hornera spinigera from Mauritius and distinguished it from Hornera pectinata Busk, 1861 in its having much smaller apertures which are, in contrast to those of H. pectinata , arranged in fascicles. According to his description, the apertures of H. spinigera are so regularly arranged, that it could be misinterpreted to be Idmonea . This arrangement of apertures was not observed in H. jeongsangi n. sp. According to Kirkpatrick’s illustration ( Kirkpatrick, 1888: pl. 10, fig. 1) colony branching is also much less dense than that of H. jeongsangi n. sp. and it has much smaller apertures (because Kirkpatrick, 1888 did not provide the exact measurements of the apertures, we estimated the diameters of apertures relative to the width of the branch). Moreover, the number of kenozooids on the frontal side of the branch seems very sparse, in contrast to the density of kenozooids in H. jeongsangi n. sp. Kirkpatrick (1888) did not describe or illustrate any gonozooid, so again comparison of this important feature is not possible.
Canu and Bassler (1929) described a new species ( H. pinnata ) from the Philippines and separated it from Hornera spinigera Kirkpatrick 1888 on the basis of having peristomes equal in length (rather than the lateral peristomes being longer as in H. spinigera ), the absence of long peristomial spines, the regular arrangement of the alternate series and the presence of shorter “pinnules” (the spiny protrusions). This species thus differs from H. jeongsangi n. sp. in having less prominent spiny protrusions. It also has a large gonozooid with a median ridge and circular ooeciopore. Moreover, the lateral peristomes in H. jeongsangi n. sp. are long, whereas those of H. pinnata are short.
Harmer (1915) described Hornera spinigera Kirkpatrick, 1888 from Siboga Expedition ( Indonesia) material. This species has usually only two, rarely three, longitudinal series of apertures, arranged in fascicles as described by Kirkpatrick (1888). The colony has branches developed more sparsely and the presence of kenozooids is not as dense as in H. jeongsangi n. sp. Harmer (1915) illustrated and described gonozooids very similar to those of H. jeongsangi n. sp. mainly because of the arrangement of the ooeciopore, which opens toward the frontal side of the colony. However, he also described sharp spines developed on the frontal surfaces of the autozooid, principally on the ridges and also on the abfrontal surfaces of the branches, where the spines may be numerous, but are shorter and conical. Such spines have not been found in H. jeongsangi n. sp. Despite these differences, the specimens described by Harmer (1915) seem the most similar and even may represent same species. While revision of hornerids are beyond the scope of this paper, we decline to synonymize these specimens.
Another similar species is Pseudoidmonea spinigera ( Kirkpatrick, 1888) described by Brood (1976) as having a similar position of the gonozooid and similar arrangement of the spiny protrusions around the aperture. It differs mainly in having less prominent spiny protrusions and smaller gonozooids that open on back side of the colony branch.
Characteristic features of the new species are the very prominent spiny protrusions around autozooidal apertures, which are not in fascicles, globular gonozooid with a chaotically, densely perforated wall with an ooeciopore observable from the frontal side of the colony. The gonozooidal wall around the ooeciopore is smooth, only perforated by minute pores, which may indicate the mixed free walled and fixed walled gonozooid. These features, together with the densely perforated abfrontal side and presence of spines only around aperture separate the described specimens from all known hornerids taxa.
Brood (1979) later established a new genus, Spinihornera , with type species Hornera spinigera Kirkpatrick, 1888 , to accommodate the hornerids with spiny protrusions around apertures. However, as his description of this new genus omitted any discussion of gonozooids and synonymised Hornera pinnata Canu and Bassler, 1929 with H. spinigera Kirkpatrick, 1888 without any thorough explanation, the status of this genus is uncertain. Therefore, we placed the new species in the Hornera , pending a detailed revision of the Horneridae , which is outside the scope of this paper.
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