Plumarella recta TAYLOR & CAIRNS & AGNEW & ROGERS 2013
Creators: name: TAYLOR, M. L.
name: CAIRNS, S. D.
name: AGNEW, D. J.
name: ROGERS, A. D.
Publisher: name: Zenodo
Year: 2013
Subjects: Biodiversity
Taxonomy
Animalia
Cnidaria
Anthozoa
Alcyonacea
Primnoidae
Plumarella
Plumarella recta

description: Plumarella recta (Nutting, 1912)   
Figs 37c,d, 38  
 Thouarella recta Nutting, 1912: 67–68, pl. 7, figs 1, 1a, pl. 19, fig. 2; Kükenthal 1919: 440–1; 1924: 302; Aurivillius 1931: 255–256   
 Thouarella (Thouarella) recta Cairns & Bayer 2009: 28 (listed)   
 Plumarella recta Cairns 2011:8   
 Material examined: Holotype, USNM 30040, R/ V Albatross, sta. 5079, south of Omae Zaki, Honshu Island, Japan, 34˚15’N, 138˚E, 475–505 m, 19 Oct 1906, 5 cm fragment.   
 Description   
The colony appears uniplanar, however, branchlets depart the main stem in 3 directions (2 rows at 160˚ creating an almost flat surface, with a third row placed sporadically along the dorsal spine at 260˚), thus it is technically bottlebrush (Fig. 37c). The ventral branchlets (in 2 rows) depart alternately from the stem. The branchlets are usually simple, sometimes forked, upwardly inclined at 60˚, and the longest branchlet is 24 mm.  
The polyps stand at 90˚ to the branchlets (Fig. 37d), 1.2–1.4 mm high, generally isolated in one plane along the branchlet, with a density of 7–9 polyps per cm, and are modestly distally flared (Fig. 38m).  
The operculum is a raised cone of 8 acute triangle-shaped operculars (Fig. 38n,c–e), 260–320 µm high (average 290 µm), 120–230 µm wide (average 165 µm), with a H:W of 1.4–2.3 (average 1.8). The distal and lateral scale edges are serrate although the lateral edges of some are pectinate whilst the proximal edges are roughly lobate. The inner surface is smooth (unkeeled) with a small patch of tubercles in the centre proximally. The outer surface is smooth with several small granules in the central proximal area.  
 Between 2 and 4 accessory operculars are found underneath the operculars (Fig. 38a,b), which are identical to those of P. alternata. They are generally less than 200 µm high and 100 µm wide, round-tipped, tongue-shaped with a small patch of tubercles at the base of the inner surface and a smooth outer surface.   
The marginal scales have a circular base with an elongated smooth distal spine. The circular base has a pectinate edge which can continue up the edges of the spine (Fig. 38f–h). These scales, 320–840 µm high (average 530 µm), 165–350 µm wide (average 220 µm), with a H:W of 1.4–3.3 (average 2.5), are too long to fold over the operculars. The adaxial marginals are smaller than those found abaxially. The inner surface is smooth with a sparsely tuberculate central circle at the base. The outer surface is smooth with few small granules towards the proximal area of the basal circle.  
The body-wall scales are mostly elliptical to fan-shaped (Fig. 38i–k), although the shape is obscured by the large pectinate lateral and distal edges. Some are smaller and placed irregularly, disrupting row placement. The body-wall scales are 190–290 µm high (average 230 µm), 255–365 µm wide (average 290 µm) with a H:W of 0.7–1 (average 0.8). The outer surface is smooth with few granules whilst the inner surface has sparse tubercules and a tuberculate proximal edge.  
The coenenchymal scales are numerous, small, and circular to elliptical in shape with finely serrate edges (Fig. 38l), 100–120 µm high (average 110 µm), 80–160 µm wide (average 125 µm), with a H:W of 0.7–1.4 (average 0.9). The inner surface has only several sparse tubercles whilst the outer surface is smooth with just a few granules.  
 Distribution   
This species is only known from the south coast of Honshu Island, Japan, at depths of 475–505 m.  
 Remarks   
 All species of Thouarella have polyps with keeled marginals, however T. recta does not, and was thus transferred to Plumarella (Cairns 2011). The mostly smooth, unkeeled inner surface of the operculars and the marginals, the elongated marginals unable to fold over the operculum, and the smooth outer surface of the body-wall scales are characters found in P. recta and common to Plumarella. Unlike Cairns (2011), we keep P. recta and P. alternata as separate species.   
The holotype is mostly denuded of polyps making the estimation of the density of polyps per cm tentative.  
The longitudinal rows of scales along the polyp body are disrupted with smaller, circular body-wall scales (see Fig. 38m), which makes counting the number of scales in the two abaxial rows difficult. Nutting (1912) counted 8–9 scales in a longitudinal row. Within this study we count 4–6 large scales in the abaxial rows, discounting smaller proximal circular scales.  
 Comparisons   
 Plumarella recta is most similar to P. alternata (see below) except that its polyps stand at 90˚ to the branchlet whereas those of the latter are at 45˚, and roughly alternating. Without being certain of the importance of this morphological feature, and despite the identical appearance of these polyps, these species are kept distinct.
description: Published as part of TAYLOR, M. L., CAIRNS, S. D., AGNEW, D. J. & ROGERS, A. D., 2013,  A revision of the genus  Thouarella  Gray, 1870 (Octocorallia: Primnoidae), including an illustrated dichotomous key, a new species description, and comments on  Plumarella  Gray, 1870 and  Dasystenella , Versluys, 1906 , pp. 1-105 in Zootaxa 3602 (1) on pages 94-97, DOI: 10.11646/zootaxa.3602.1.1, http://zenodo.org/record/5259143