taxonID	type	description	language	source
941F02396458FFDAFF2EFA45FE60FC27.taxon	diagnosis	Diagnosis. Sertulariidae with erect, branched colonies, with branches resembling hydrocaulus. Hydrothecae arranged in 5 – 8 longitudal rows along hydrocaulus and branches; hydrothecal rim with four very low cusps separated by shallow embayments; operculum of four equal triangular valves, flattened rather than pyramidal; hydranth with abcauline caecum. Gonothecae oval with strong transverse corrugations and rings, occurring in opposite pairs on lower part of stem.	en	Antsulevich, Alexander (2011): Polysertularella polyseriata, a new genus and species of hydroid (Hydrozoa; Leptothecata; Sertulariidae) from the Sea of Okhotsk. Zootaxa 3107: 59-64, DOI: 10.5281/zenodo.202210
941F02396458FFDAFF2EFA45FE60FC27.taxon	materials_examined	Type species. Polysertularella polyseriata, sp. n., designated herein. Notes and differential diagnosis. In most genera of Sertulariidae, hydrothecae have an alternate to opposite biserial arrangement on branches, and especially on the stem. A few genera in the family, including Abietinaria Kirchenpauer, 1884, Thuiaria Fleming, 1828, Sertularia Linnaeus, 1758, and Staurotheca Allman, 1888 include some species with multi-serial rows of hydrothecae on branches and very rarely on the stem as well. The nominal genus Selaginopsis Allman, 1876, originally established for sertulariids having hydrothecae in more than two longitudinal rows, is no longer recognized as valid in some works because of its artificial composition and differences among included species in operculum structure (Peña-Cantero et al., 1997). However, no species with a multiserial arrangement of hydrothecae and four-flapped operculum (resembling Sertularella) has been known in the family until now. Polysertularella is phylogenetically close to the well-known and widely distributed sertulariid genus Sertularella Gray, 1848. Their relationship is apparent from the similar four-flapped operculum, the four-cusped hydrothecal aperture, and the general structure of their gonothecae. The latter resemble those of many species of Sertularella, Symplectoscyphus Marktanner-Turneretscher, 1890, and some other genera in the family. Distinctive characters of the new genus are as follows. Gonothecae arise from the apertures of tubular processes borne in opposite pairs on the stem that resemble and are probably homologous to hydrothecae. Insertion of gonothecae thus differs from that observed in Sertularella and Symplectoscyphus, in which gonothecae normally arise near the hydrothecal base. Gonothecal arrangement is superficially similar to that in Synthecium Allman, 1872 (family Syntheciidae), a genus with hydrothecae in opposite pairs and with gonothecae arising from the hydrothecal orifices (Millard 1975; Vervoort, Watson 2003). However, Polysertularella and Synthecium are not closely related because species of the latter lack an operculum (Millard 1975; Vervoort & Watson 2003; Bouillon et al. 2006). Expanding the scope of Sertularella to accommodate the new species, with its multi-serial arrangement of hydrothecae, is inexpedient. Sertularella is already the largest genus in Hydrozoa, and all of some 300 nominal species of this genus have biseriate and alternately arranged hydrothecae, according to recent generic diagnoses (Naumov 1960; Calder 1991; Vervoort 1993; Cornelius 1995; Hirohito 1995; Bouillon et al. 2006). Certain morphological characters observed on the type colony may be important, but were not included in the diagnosis of the new genus because of a shortage of material. These included the polysiphonic common stolon, and the origin of gonothecae from the apertures of hydrotheca-like processes. The generic name Polysertularella reflects both the multi-serial arrangement of hydrothecae and the relationship of the genus to Sertularella, as apparent from hydrothecal and gonothecal shape, and opercular structure. The gender of the name is feminine.	en	Antsulevich, Alexander (2011): Polysertularella polyseriata, a new genus and species of hydroid (Hydrozoa; Leptothecata; Sertulariidae) from the Sea of Okhotsk. Zootaxa 3107: 59-64, DOI: 10.5281/zenodo.202210
941F02396459FFDFFF2EFC24FC57F97C.taxon	materials_examined	Material. One mature and fertile colony. Holotype: R. V. “ Akademik Oparin ”, Pacific Ocean, eastern part of the Sea of Okhotsk near middle part of Kuril Islands, coordinates 47 о 22 ’ N; 152 o 10 ’ E, collected 1 July 1988 by Eugeny Gruzov, Zool. Inst. of Russian Acad. Sci., St. Petersburg (ZI RAS); bottom trawl, depth 146 m. Specimen No 11211 in the systematic collection of Department of Porifera & Cnidaria of ZI RAS.	en	Antsulevich, Alexander (2011): Polysertularella polyseriata, a new genus and species of hydroid (Hydrozoa; Leptothecata; Sertulariidae) from the Sea of Okhotsk. Zootaxa 3107: 59-64, DOI: 10.5281/zenodo.202210
941F02396459FFDFFF2EFC24FC57F97C.taxon	description	Description. Colony erect, tree-like, irregularly branched, 7.5 cm high (Fig. 1). Primary common stolon (or primary stem?) consisting of thick tubes, root-like, unplaited at base of common stolon. Tubes anastomosing and densely braided on stolon and sometimes even on proximal parts of secondary stems and (or) primary branches. Bases of secondary stems separated from common stolon by several thick annulations. Hydrocaulus differing from branches only in having thicker perisarc; hydrothecae arranged in eight longitudinal rows on hydrocaulus. Branches bifurcate dichotomously several (up to five) times. Lower branches of older orders (1 st and 2 nd) more thickened, hydrothecae again arranged in eight rows. Towards distal regions of colony, branches of next orders becoming slightly thinner and with hydrothecae arranged in six and in five rows (Fig. 2). At tips of distal branches, hydrothecae may occur in four cross-wise rows. Hydrothecal rows very close to one other, but along a given row hydrothecae widely separated, with distance between adjacent ones usually exceeding hydrothecal length. Hydrothecae of three adjacent rows arranged as in “ chess cells ” (as in many other sertulariids with multi-serial hydrothecae), allowing neighbouring hydranths space for feeding. Hydrothecae normally about 3 / 4 adnate, distal part always free. Hydrothecae from proximal and distal parts of colony may be slightly unequal in shape; in distal regions of branchlets, hydrothecae may be less adnate – about 2 / 3. Perisarc of hydrothecae thick, especially on abcauline wall; abcauline wall almost straight to slightly concave, then slightly curved in opposite direction (toward the branch) just below the rim so that entire abcauline wall has very gentle S - shape profile; “ distal ” hydrothecae usually somewhat more curved than “ proximal ” ones. Hydrothecal aperture forming an angle of about 45 o with branch axis in “ distal ” hydrothecae, but may be nearly at right angles in “ proximal ” ones. Hydrothecal aperture square, with rounded corners; rim with four short, equal cusps separated by shallow embayments. The operculum consists of four equal triangular valves, flattened and almost in one plane rather than pyramidal as in most species of Sertularella. The hydranth has 12 – 16 filiform tentacles; abcauline caecum present (Figs. 2, 3). Gonothecae on lowest part of shoots only, at base of secondary stems just above annulations; arising in opposite pairs from apertures of tubular hydrotheca-like processes on two sides of stem; equal pairs of gonothecae found only on two shoots of colony. Gonothecae oval, with 6 - 7 well developed sharp transverse corrugations; distal end with short, thin neck; top of neck with or without apical widening in shape of trumpet; apical spines absent (Fig. 4). Dimensions (mm): stolon tube diameter 0.21 – 0.35. Hydrotheca: abcauline wall 0.42 – 0.56; free part of adcauline wall (in hydrothecae from proximal and medial regions of colony) 0.07 – 0.08; same for hydrothecae on distal region of colony or branches 0.11 – 0.15; aperture width 0.20 – 0.22. Gonotheca: height 2.17 – 2.31; maximal width 1.47 – 1.61.	en	Antsulevich, Alexander (2011): Polysertularella polyseriata, a new genus and species of hydroid (Hydrozoa; Leptothecata; Sertulariidae) from the Sea of Okhotsk. Zootaxa 3107: 59-64, DOI: 10.5281/zenodo.202210
941F02396459FFDFFF2EFC24FC57F97C.taxon	distribution	Distribution. The species is known only from the type locality. Notes. Hydroids of Polysertularella polyseriata demonstrate that multi-serial arrangement of hydrothecae exists amongst sertulariids having opercula with four valves, as well as in those having a different opercular shape. Convergent evolution is thus evident within this family, and the arrangement increases the number of feeding hydranths on a colony. It is likely that other hydroids with multi-serial rows of hydranths exist in Sertulariidae. The arrangement of hydrothecae and hydranths in the form of “ chess cells ” minimizes overlapping of feeding areas and makes colonial prey capture more effective. The specific name “ polyseriata ”, an adjective agreeing in gender with the feminine generic name Polysertularella, reflects the main morphological character of the colony structure – multi-serial arrangement of hydrothecae. I am endebted to Dr. Evgeny Gruzov, a famous Russian investigator of polar oceans and my first teacher of marine biology. This work was undertaken without any financial support.	en	Antsulevich, Alexander (2011): Polysertularella polyseriata, a new genus and species of hydroid (Hydrozoa; Leptothecata; Sertulariidae) from the Sea of Okhotsk. Zootaxa 3107: 59-64, DOI: 10.5281/zenodo.202210
