A new species of Pachycerianthus (Cnidaria, Anthozoa, Ceriantharia) from Tropical Southwestern Atlantic Author Stampar, Sérgio N. Departamento de Ciências Biológicas, Faculdade de Ciências e Letras, Unesp - Univ Estadual Paulista, Assis, Av. Dom Antonio, 2100, Assis, 19806 - 900, Brazil stampar@assis.unesp.br Author Morandini, André C. Author Silveira, Fábio Lang Da text Zootaxa 2014 2014-07-04 3827 3 343 354 journal article 5313 10.11646/zootaxa.3827.3.4 1dabe90e-f864-4fad-8c0c-08cb810fd983 1175-5326 4920732 8D9FB4C3-3BDF-4ED5-A573-24D946AFCA71 Pachycerianthus schlenzae sp. nov. Figs 1–3 Material examined ( 5 specimens ). Holotype : MZUSP 1949 , adult specimen ( 15 cm long), 5 m depth , Guaibura Beach ( 20°43'39.2"S 40°31'17.7"W ), Guarapari, Espírito Santo state , Brazil , S.N. Stampar coll. ( 10/12/2008 ) ( I ). Paratypes : MNRJ 2852 , adult specimen ( 13 cm long), 6 m depth , Viçosa Reef ( 17°58’59.4”S 39°16’34.2”W ), Nova Viçosa , Bahia state , Brazil , C.C. Ratto & D.O. Pires coll. ( 02/04/1996 ) ( II ) . MNRJ 2016 , adult specimen ( 12 cm long), Spin Reef ( 17°05’45”S 39°09’47”W ), Cumuruxatiba , Bahia state , Brazil , F.B. Pitombo coll. ( 01/30/ 1991 ) ( III ) . MNRJ 4286 , young specimen ( 8 cm long), Abrolhos ( 17°21’01.6”S 38°57’26.5”W ), Bahia state , Brazil , P.C. Paiva coll. ( 02/27/2000 ) ( IV ) . MZUSP 1950 , adult specimen ( 15 cm long), 6 m depth , Baixa de Carapebús ( 20°14'47.55''S 40°12'0.617''W ), Vitória , Espírito Santo state , Brazil , M.S.C da Hora coll. ( 10/20/2011 ) ( V ) . Diagnosis . Average length cerianthid ( 150 mm long). Marginal tentacles 60–85, to 120 mm long in living animals, 25–30 mm in preserved specimens, brown or purple with purple tips; 9–20 white dots along each tentacle ( Fig. 1 ), arrangement 4132.3132.4132.3132 , with more than 20 pores per each tentacle. Labial tentacles 60–80, to 40 mm long in living animals, 10–20 mm in preserved specimens, pale brown or whitish, arrangement (2)213.2132.1321.2132 , unpaired labial tentacle present. Stomodeum long, extending 1/3 to 1/4 of total body length, hyposulcus 2 mm long, hemisulci distinct; siphonoglyph narrow, connected to first three mesenterial couples. Free part of sterile directive mesenteries same length to twice length of siphonoglyph. Second protomesenteries sterile, longer than directives but short and with few craspedonemes. Third protomesenteries sterile, shorter than directives; M and m-metamesenteries long, fertile; M 1 reaching aboral pore, with bundle of craspedonemes; B and b-mesenteries sterile; see Fig. 2 for schematic arrangement of mesenteries. The cnidome ( Fig. 4 , Table 2 ) is composed of spirocysts, atrichs (I–II), microbasic b-mastigophores (I–V), and ptychocysts. TABLE 2 . Comparison of the cnidome of tropical shallow species of Pachycerianthus occurring on the Atlantic Ocean. Measurements expressed as length and width of 30 undischarged capsules (n = 3 specimens), data appear as the mean (minimum–maximum) values.

Pachycerianthus schlenzae sp. nov.	Pachycerianthus curacaoensis
length x width (in µm)	length x width (in µm)
Column
Pytchocysts	55.19 (46.8–62.92) x 17.47 (15.2–19.76)	53.74 (49.4–63.44) x 20.12 (16.64–23.4)
Atrichs II	51.27 (47.84–54.6) x 15.52 (13.52–18.2)	49.71 (41.6–61.36) x 18.77 (18.2–20.8)
b-mastigophores I	40.32 (33.8–44.72) x 7.59 (6.24–9.36)	40.56 (37.44–42.64) x 7.59 (6.76–8.32)
b-mastigophores II	26 (23.4–30.16) x 4.99 (4.16 x 5.72)	30.1 (26–33.28) x 5.77 (5.2–6.76)
Marginal Tentancles	b-mastigophores I	35.46 (34.84–37.44) x 7.8 (6.76–8.32)	29.45 (28.6–30.68) x 5.12 (4.68–5.2)
b-mastigophores III #	29.12 (27.04–30.68) x 5.14 (4.68–5.2)	20.04 (16.64–21.84) x 2.7 (2.6–3.12)
Labial Tentacles	b-mastigophores I #	40.48 (38.48–42.64) x 7.46 (6.76–7.8)	29.56 (27–31.2) x 4.6 (4.16–5.2)
b-mastigophores III #	27.4 (26–28.6) x 3.27 (2.6–4.1)	20.8 (18.2–21.84) x 2.57 (2.08–3.12)
Atrichs #	35.93 (29.1–41.08) x 7.33 (6.24–8.32)	27.11 (24.9–30.1) x 5.17 (4.6–5.2)
Stomodeum
b-mastigophores I	29.56 (22.56–31.35) x 6.55 (5.89–7.35)	22.99 (20.8–24.7) x 4.12 (3.9–4.42)
b-mastigophores III	26.1 (24.2–27.8) x 3.15 (2.6–3.9)	25.89 (23.92–28.08) x 7.43 (6.76–7.8)
Atrichs	36.82 (32.1–42.35) x 7.52 (6.8–8.5)	32.24 (28.6–35.36) x 6.26 (5.72–6.76)
Mesenteries Type B	b-mastigophores I #	48.88 (42.64–53.06) x 8.24 (7.8–8.84)	33.17 (28.6–36.4) x 5.94 (5.2–6.76)
b-mastigophores III #	27.3 (24.96–31.2) x 6.5 (5.2–7.28)	20.17 (17.16–23.4) x 5.22 (5.2–5.72)
Atrichs	31.9 (28.6–35.36) x 7.51 (6.2–8.32)	30.68 (26–37.44) x 5.66 (5.2–6.24)
Mesenteries Type M	b-mastigophores IV	25.97 (21.84–28.08) x 5.46 (4.68–6.24)	29.36 (27–31.2) x 4.8 (4.2–5.4)
b-mastigophores V #	16.51 (13.5–18.72) x 4.83 (4.16–5.2)	21.8 (18.2–21.84) x 2.72 (2.23–3.24)
Atrichs	--	27.21 (24.3–31.1) x 5.17 (4.6–5.2)

Distribution . Brazil , from Bahia to Espírito Santo states (Abrolhos Bank and Royal Charlotte Bank) ( Fig. 3 ). The southernmost record is from Guarapari, Espírito Santo state ( 20°43'39"S 40°31'17"W ) and the northernmost record is from Camamu Bay, Bahia state ( 13°53'19"S 38°57'38"W ). FIGURE 1. Pachycerianthus schlenzae sp. nov. : A—Live specimen from Guarapari-ES (Holotype—MZUSP1949), B—Live specimens at Camamu Bay-BA, Image only (Image: Claudio Sampaio), C and D—Live specimen at Porto Seguro-BA, Image only (Images: Rodrigo Maia-Nogueira), E—General view of the mesentery just below the stomodeum (scale 1 cm) (Holotype—MZUSP1949), F—Detail of fertile mesenteries with many oocytes (scale 6 mm) (Holotype—MZUSP1949). Etymology . The specific name “ schlenzae ” honors Dr. Erika Schlenz (retired researcher from the Zoology Department, University of São Paulo , Brazil ). Dr. Schlenz is a well-known actiniarian specialist, and she supervised many researchers working with cnidarians in Brazil . Color variation . The color of the marginal tentacles varies from yellowish brown to deep purple, but tentacles always have white spots. The labial tentacles are always very light from beige to deep white. Symbiosis . None of the tubes of Pachycerianthus schlenzae had Phoronida associated with them as had been observed by Stampar et al. (2010) for Cerianthemorphe . Some tubes bore colonies of a bryozoan, Fenestrulina commensalis also firstly described from the same area ( Vieira & Stampar, 2014 ). FIGURE 2 . Graphical representation of the arrangement of mesenteries of Pachycerianthus schlenzae sp. nov. Abbreviations: B—B-mesenteries, b—b-mesenteries, D—Directives, E—Stomodeum, M—M-mesenteries, m—m-mesenteries, M.C.—Multiplication chamber, S—Siphonoglyph, T.P.—Terminal pore. FIGURE 3 . Distribution of Pachycerianthus schlenzae sp. nov. along the Brazilian coast. A— Bahia and Espirito Santo States in South American Map; B— Detail of Bahia (BA) and Espirito Santo (ES) States, the black circles correspond to specimens analyzed with the corresponding numbers presented in the "Material examined". FIGURE 4. Cnidome of Pachycerianthus schlenzae sp. nov. A—ptychocysts, B—atrichs type II, C—atrichs type I/ ptychocysts, D—microbasic b-mastigophores I, E—microbasic b-mastigophores II, F—microbasic b-mastigophores III, G—microbasic b-mastigophores IV and H—microbasic b-mastigophores V. Scale 10µm. Description of holotype (MZUSP 1949). Polyp elongate, length 14 cm , diameter 25 mm just below marginal tentacles and 20 mm near aboral end. Marginal tentacles 82, arranged in 4 pseudocycles, 50– 40 mm long and 6– 5 mm in diameter near base, brownish-yellowish at base, purple at tips. Space between cycles of marginal and labial tentacles dark red. Labial tentacles 72, about 30 mm long, bright white with white longitudinal line, directive labial present. Arrangement of marginal tentacles 4132.3132.4132.3132… and labial tentacles (2)213.2132.1321.2132 .... Oral disk 2 cm wide, stomodeum 42 mm long, light brown, siphonoglyph narrow and elongate with 6 mesenteries attached, hyposulcus 7.5 mm long with short ( 3 mm ) hemisulci. Free part of directive mesenteries 40 mm long, without mesenterial filament. Second protomesenteries (p 2 ) relatively short with developed mesenterial filament: 39 mm with fairly developed craspedonemes. Third protomesenteries short (p 3 ) about 19 mm with developed craspedonemes and cnidoglandular tract. Metamesenteries in quartets: MBmb, metamesenteries of first cycle (M 1 ) reach aboral pore, have craspedonemes up to aboral region; remaining type M mesenteries exhibit same basic morphology, reaching no less than half of column, with numerous craspedonemes uniformly arranged until 4/5 of the mesentery length; mesenteries type m same as type M only shorter; metamesenteries type B and b, sterile, short, each with bunch of craspedonemes. Morphological remarks. The specimens observed varied much more in the coloration of tentacles than in internal anatomy. The mesenteries have the same size ratio in relation to column length as the described specimen. The arrangement of the tentacles was also constant in all observed specimens. The craspedonemes range in length from 1- 4 mm and are always arranged in the upper region of the mesentery. The number of craspedonemes varies greatly between mesenteries of the same type in the same specimen, however craspedonemes are always present. Comparison with other species of Pachycerianthus . Morphological aspects. Pachycerianthus comprises 16 species in addition to the one described here. All species of the genus were compared with the new species and were compared based on the analysis of type materials or on the original species description. The species of Pachycerianthus can be split into two groups based on the relative length of the directive mesenteries and the stomodeum. The directive mesenteries are longer than the stomodeum in Pachycerianthus schlenzae sp. nov. , whereas in Pachycerianthus benedeni , P. insignis , P. johnsoni , P. maua , P. multiplicatus , and P. solitarius , the directive mesenteries are shorter than the stomodeum. A second attribute that can be used to discriminate species is the length of M1 mesenteries: in Pachycerianthus schlenzae sp. nov. , M1 reach the aboral pore; in P. delwynae , P. dohrni , P. fimbriatus and P. magnus , M1 mesenteries are shorter and do not reach the pore. Another differentiating characteristic is the number of mesenteries attached to the siphonoglyph region: Pachycerianthus schlenzae sp. nov. has 6 mesenteries attached, whereas P. curacaoensis , P. borealis , P. monotichus , and P. aestuari have 4, 8, 8 and 16, respectively. Finally it is possible to distinguish the remaining species in relation to Pachycerianthus schlenzae sp. nov. by the number of tentacles: Pachycerianthus schlenzae sp. nov. has up to 85 tentacles, wheras P. longistriatus and P. nobilis have at least 140 in adult specimens. Species from related biogeographical area. Only three members of Pachycerianthus have been recorded from Atlantic waters: Pachycerianthus borealis ( Danielssen, 1860 ) from the coast of Canada and northern USA (1–50 meters); Pachycerianthus multiplicatus Carlgren, 1912 from North Sea (10–130 meters); and Pachycerianthus curacaoensis den Hartog, 1977 from Curaçao (Caribbean) (65–75 meters). These differ from one another and from P. schlenzae sp. nov. in the number of marginal tentacles: P. borealis (140–160), P. multiplicatus (160–170), P. curacaoensis (74–105), and P. schlenzae sp. nov. (60–85). Another obvious difference are the white spots in the marginal tentacles in P. schlenzae sp. nov. and P. curacaoensis , which are absent from the other two species; however this feature is not visible some time after preservation. Features of internal anatomy also differentiate the Atlantic species. The length of stomodeum in P. borealis is about 1/6 of the total length of the column; this ratio increases to around 1/ 3 in P. schlenzae sp. nov. At least five couples of M-mesenteries reach the region of the aboral pore in P. borealis , whereas in P. schlenzae sp. nov. only one couple of M-mesenteries reaches the aboral pore. Specimens of P. multiplicatus have at least five couples of M-mesenteries that reach the aboral pore. The Caribbean species P. curacaoensis and the Brazilian P. schlenzae sp. nov. differ in subtle ways. The external morphology (number of tentacles and color pattern) is similar in both species. However, the stomodeum in P. curacaoensis extends about 1/8 to 1/12 of the total length of the body; in contrast, the stomodeum in P. schlenzae sp. nov. is about 1/3 to 1/4 of the total length of the body. The number of mesenteries attached to the syphonoglyph is also different: 4 in P. curacaoensis and 6 in P. schlenzae sp. nov. In P. curacaoensis , only the couple M 1 exceeds half of the column, whereas in P. schlenzae sp. nov. at least 8 pairs of M-mesenteries (M 1 –M 8 ) exceed half of the column length. The two species differ in the size of cnidae (see Tables 2 , 3 ). Comparative anatomical characters for all known species of Pachycerianthus are presented in Table 4. Molecular aspects. Molecular markers have been used as a tool for the taxonomy of Ceriantharia (Rodriguez et al. , 2012; Stampar et al. , 2012 ; Stampar & Morandini, 2014 ). The results ( Table 5 ) showed that the discrepancies between the molecular markers of the species of Pachycerianthus are considerable, as was also shown by Stampar et al. (2012) for species of Isarachnanthus . TABLE 3 . Mann-Whitney test comparing the length of cnidae in Pachycerianthus curacaoensis and P. schlenzae sp. nov. (only comparisons with statistical significance). See Table 2 for measurements. Note that p-values smaller than 0.05 indicate that that samples are different.

Cnidae	Body part	P-value
b-mastigophore I	Labial tentacle	<0.0001
b-mastigophore I	Mes. type B	<0.0001
b-mastigophore III	Mes. type B	<0.0001
b-mastigophore II	Marginal tentacle	<0.0001
b-mastigophore III	Labial tentacle	<0.0001
b-mastigophore V	Mes. type M	<0.0001
Atrichs	Labial tentacle	<0.0001

Remarks on general taxonomy. The species described in this study is distinguishable by a number of features. However, to describe it and differentiate it from other species of the genus required careful re-examination of the genus Pachycerianthus as well as the entire family Cerianthidae , both using morphology to refine the descriptions of certain species and collecting molecular data from a several species. At the same time it is necessary to understand the morphological variation within each species and always associate it with genetic variation. Some studies have addressed morphological variation within some morphotypes ( e.g. Carlgren, 1912 ; van Beneden, 1924 ), unfortunately there is no confidence that these specimens belong in fact to the same species; maybe there are cryptic species within. The issue of cryptic species was only addressed for Ceriantharia recently ( Stampar et al. , 2012 ), but it is widely recognized on other groups ( e.g. Zoanthidae — Reimer et al. , 2006 ). This type of study may not provide relevant results for species with a very restricted distribution, such as Pachycerianthus schlenzae sp. nov. However, some ceriantharian species ( eg. Ceriantheomorphe brasiliensis ) have very wide distribution and these species may present interesting results with respect to discrepancies between morphological and molecular differences. Biological aspects. Two specimens of P. schlenzae sp. nov. were maintained in aquarium for three years (2009–2011). These specimens were maintained on a closed aquarium system (5000L) under natural light regime and constant temperature (21°C). In early spring ( Sep 2009 ), both specimens released many oocytes. This event was restricted to one day. After more than two months, few days before the beginning of summer ( Dec 2009 ), one of the individuals released sperm, two or three times per day, over four days. In late summer ( Feb 2010 ), a new release of gametes occurred, however this event was different since both sperm and oocytes were released simultaneously. Once again the liberation of oocytes lasted only one day and was continuous, and the release of sperm was episodic and took four days. The oocytes were yellow to brown color with a mean diameter of 190 µm (± 30µm ). Identical events were observed during the next seasons (2010–2011). In both cases and in late summer, we mixed up gametes of both sexes but fertilization was not observed. Uchida (1979) accomplished fertilization for Pachycerianthus magnus using the same methods.