Pholoe microantennata, Padovanni, Nathalia & Amaral, Antonia Cecília Z., 2013

Padovanni, Nathalia & Amaral, Antonia Cecília Z., 2013, New species of the scale worm genus Pholoe (Polychaeta: Pholoidae) from southeast Brazil, Zootaxa 3710 (5), pp. 485-497 : 486-490

Pholoe microantennata sp. nov.

( Figures 1–3 )

Material Examined. Holotype: ZUEC 10400; 21º55'51,246"S - 40º25'58,216"W; 49 m; 23 Jul 2009; 1 spm.

Paratypes (8 specimens): ZUEC 11405; 22º19'32,127"S - 40º37'18,980"W; 75 m; 15 Mar 2009; 4 spm. ZUEC 11404; 22º1'46,032"S; 40º44'52,588"W; 27 m; 26 Feb 2009; 1 spm. ZUEC 11403; 22º19'31,871"S - 40º37'18,979"W; 73 m; 0 4 Jul 2009; 1 spm. ZUEC 11402; 22º3'45,901"S - 40º9'59,704"W; 75 m; 0 6 Jul 2009; 1 spm. ZUEC 11384; 22º1'45,808"S - 40º44'51,839"W; 28 m; 26 Feb 2009; 1 spm.

Non-type material: (74 specimens): ZUEC 6148; 23º20’0”S - 41º22’0”W; 110 m; 28 Feb 1998; Box-corer; 1 spm. ZUEC 6175; 21º51’77”S – 40º07’49”W; 110 m; 0 2 Mar 1998; 1 spm. ZUEC 6177; 29o14’672”S – 47o50’669”W; 106 m; 22 Mar 1998; 1 spm. ZUEC 8866; 23º58'10"S – 45º29'44"W; 45 m; 13 Feb 2001; 1 spm. ZUEC 8905; 23º36'50"S - 45º19'32"W; 5 m; 16 Feb 2002; 1 spm. ZUEC 8868; 23º 34'11"S – 45º04'35"W; 25 m; 23 Mar 2001; 1 spm. ZUEC 8867; 23º36'25"S – 45º17'10"W; 10 m; 26 Apr 2001; 1 spm. ZUEC 8865; 23º41'27"S – 44º11'42"W; 25 m; 30 Jul 2001; 1 spm. ZUEC 10377; 22º41'46,694"S – 41º53'46,121"W; 30 m; 16 Mar 2009; 2 spm. ZUEC 10383; 22º41'47,098"S – 41º53'46,452"W; 30 m; 16 Mar 2009; 6 spm. ZUEC 10394; 22º59'47,416"S – 41º21'7,937"W; 78 m; 21 Feb 2009; 1 spm. ZUEC 10398; 22º46'54,978"S – 41º3'32,960"W; 77 m; 22 Feb 2009; 1 spm. ZUEC 10393; 22º46'54,841"S – 41º3'33,651"W; 78 m; 22 Feb 2009; 1 spm. ZUEC 10391; 22º19'32,030"S – 40º37'18,991"W; 75 m; 15 Mar 2009; 1 spm. ZUEC 10382; 22º19'32,134"S – 40º37'19,109"W; 75 m; 15 Mar 2009; 1 spm. ZUEC 10376; 22º19'32,127"S – 40º37'18,980"W; 75 m; 15 Mar 2009; 1 spm. ZUEC 10372; 22º1'46,032"S – 40º44'52,588"W; 27 m; 26 Feb 2009; 3 spm. ZUEC 10379; 22º1'45,700"S – 40º44'52,329"W; 28 m; 26 Feb 2009; 1 spm. ZUEC 10375; 22º3'41,591"S – 40º24'8,812"W; 56 m; 25 Feb 2009; 1 spm. ZUEC 10397; 22º3'45,625"S – 40º9'59,188"W; 75 m; 25 Feb 2009; 9 spm. ZUEC 10381; 22º3'45,395"S – 40º9'59,684"W; 75 m; 25 Feb 2009; 5 spm. ZUEC 10373; 22º3'45,351"S – 40º9'59,386"W; 75 m; 25 Feb 2009; 3 spm. ZUEC 10387; 22º41'46,466"S – 41º53'46,036"W; 30 m; 12 Jul 2009; 3 spm. ZUEC 10386; 22º59'47,377"S – 41º21'7,716"W; 77 m; 0 2 Jul 2009; 1 spm. ZUEC 10389; 23º10'5,207"S – 41º3'6,453"W; 107 m; 0 2 Jul 2009; 2 spm. ZUEC 10395; 22º37'31,715"S – 41º21'52,696"W; 54 m; 16 Jul 2009; 2 spm. ZUEC 10388; 22º19'31,871"S – 40º37'18,979"W; 73 m; 0 4 Jul 2009; 1 spm. ZUEC 10371; 22º23'39,088"S – 40º20'41,226"W; 150 m; 0 4 Jul 2009; 1 spm. ZUEC 10390; 21º59'4,307"S – 40º25'10,520"W; 52 m; 0 6 Jul 2009; 1 spm. ZUEC 10380; 22º3'45,789"S – 40º9'58,844"W; 75 m; 0 6 Jul 2009; 1 spm. ZUEC 10378; 22º3'45,901"S – 40º9'59,704"W; 75 m; 0 6 Jul 2009; 3 spm. ZUEC 10396; 22º3'39,049"S – 40º6'59,816"W; 90 m; 0 6 Jul 2009; 1 spm. ZUEC 10392; 21º42'53,895"S – 40º10'14,920"W; 97 m; 0 7 Jul 2009; 1 spm. ZUEC 10385; 21º42'37,864"S – 40º8'59,557"W; 147 m; 0 7 Jul 2009; 1 spm. ZUEC 10384; 21º9'9,705"S – 40º16'6,779"W; 103 m; 21 Jul 2009; 3 spm. ZUEC 10374; 21º9'9,286"S – 40º16'7,457"W; 103 m; 21 Jul 2009; 2 spm. ZUEC 10399; 21º44'44,245"S – 40º43'9,558"W; 21 m; 19 Jul 2009; 1 spm. ZUEC 10401; 22º1'9,406"S – 40º31'55,389"W; 49 m; 24 Jul 2009; 3 spm. ZUEC 10402; 22º1'7,705"S – 40º31'53,782"W; 49 m; 24 Jul 2009; 1 spm. ZUEC 11383; 23º11'29,016"S – 41º0'49,451"W; 106 m; 21 Feb 2009; 1 spm. ZUEC 11386; 21º23'3,454"S- 40º15'10,559"W; 142 m; 0 6 Mar 2009; 1 spm.

Description: Size range of material examined 1.2–7.5 mm long (holotype 7.5 mm), 0.3–1.2 mm wide (holotype 0.7 mm), 19–55 segments (holotype 55 segments). Body of uniform width, tapering markedly at both ends, flattened dorsoventrally ( Fig. 1 A); ventral surface of body and parapodia with globular papillae.

Prostomium and tentacular segment are fused ( Fig. 1 A–C); prostomium triangular and bilobed; large ceratophore of median antenna in anterior notch ( Fig. 1 B–F); two small lateral antenna, more or less hidden by the ceratophore of the median antenna, are present ( Fig. 1 E–G). Two pairs of brownish eyes ( Fig. 1 A–B). Tentaculophores attach laterally relative to the prostomium; tentaculophores achaetous, longer than median antenna and with scattered papillae; each has subequal dorsal and ventral tentacular cirri, ( Fig. 1 D–E, H). Palps stout, extending ventral and lateral to tentaculophores, with rugose surface and rows of minute papillae ordered longitudinally. Minute papillae on the palp bases may be present ( Fig. 1 H). Facial tubercle inconspicuous. Eversible muscular pharynx with nine dorsal and nine ventral border papillae and two pairs of jaws.

Elytra and elytrophores are present on segments 2, 4, 5, 7, and continuing on alternate segments to 23, then on every segment to end of body; elytra covering the dorsum completely ( Fig. 2 A). Dorsal tubercles nodular. Elytra are pale, oval to retangular in shape ( Fig. 2 B–E), and become larger toward the posterior region ( Fig. 2 A); elytra with large and conical papillae on margin, submargin and surface ( Fig. 2 B–E), each papillae with blunt, expanded tip bearing delicate cilia ( Fig. 2 F–G).

Parapodia biramous ( Fig 3 A–B); notopodia smaller than neuropodia ( Fig. 3 B), with conical acicular lobe and subdistal bractea ( Fig. 3 B–C); notopodial lobes with stylodes distally ( Fig. 3 B–D) and cilia on posterior region ( Fig. 3 A); neuropodia with stylodes in all extension ( Fig. 3 B). Notochaeta of two kinds: long, spinous capillaries ( Fig. 3 E) and shorter, strongly bent, spinous capillaries ( Fig. 3 C–D). Neurochaetae stouter than notochaeta, compound, with shafts spinous subdistally and blades short, spinous, falcate with unidentate tips ( Fig. 3 F–G). Ventral cirri papillate, shorter than neuropodia. Pygidium with a pair of anal cirri.

Etymology. The name P. microantennata was chosen duo to the minute lateral antenna that this species possesses.

Geographic and bathymetric distribution. Brazil: northern coast of São Paulo State and Campos Basin, in sandy sediment, at depths of 5 to 150 m.

Discussion. The genus Pholoe contains 16 valid species (Fauchald et al. 2012), which are compared in Table 2.

In addition to P. microantennata sp. nov., only three other Pholoe species have lateral antennae: P. baltica , P. longa and P. courtneyae . The primary differences between P. microantennata sp. nov. and P. longa are: (i) Position of the lateral antennae: in P. longa they are located on the ventral tentacular cirri (Pettibone 1992, Fig. 1 C), whereas in P. microantennata sp. nov. they are extensions of the prostomium; (ii) Elytral papillae: they are distinctly annulated in P. longa and are large and conical in P. microantennata sp. nov.; (iii) Dark pigment between eyes: it is absent in P. microantennata sp. nov. and it is present in P. longa ; (iv) Notochaeta: with diagonal rows of spinous in P. microantennata sp. nov. and finely spinose in P. longa . Compared with P. courtneyae , the primary differences are the absence of eyes and elytra with long and slender papillae, opposed to the presence of four eyes and elytra with large and conical papillae in P. microantennata sp. nov. According to Petersen (1998), Pholoe baltica is identical to P. longa , and thus, it has the same differences in properties from P. microantennata sp. nov.

As the lateral antennae of Pholoe microantennata sp. nov. can be difficult to visualize in certain individuals, this species can be confused with P. inornata and P. m i nu t a. In both cases, the differences between the elytral papillae (which are slightly annulated in P. inornata , annulated in P. minuta and large and conical in P. microantennata sp. nov.) may be the best feature for differentiating the species.

Pholoe microantennata sp. nov. also exhibits similar characteristics as Pholoe sp. A (Wolf 1984, p. 25-7, fig. 25.2). The author describes "tentaculophores with small papilla on either side of median antenna", which are likely the lateral antennae of P. microantennata sp. nov. Moreover, the elytral papillae of Pholoe sp. A are "large and conical", similar to those found in P. microantennata sp. nov. ( Fig. 1 B–G). Thus, based on the description by Wolf (1984), Pholoe sp. A and P. microantennata sp. nov. are likely the same species.

Figures

FIGURE 1. Pholoe microantennata sp. nov. A. completed specimen without elytra, dorsal view; B, C. anterior region of body without elytra, dorsal view; D. prostomium, dorsal view; E, F. prostomium, dorsal view, with details of lateral antennae; G. right lateral antenna; H. anterior region, dorsal view. MA — median antenna, LA — lateral antenna, TC — tentacular cirrus, P — palp, VC — ventral cirrus, Pa — papillae.

FIGURE 2. Pholoe microantennata sp. nov. A. anterior region of body, with elytra, dorsal view; B, C, D. elytra from anterior region; E. elytra from posterior region; F, G. details of the elytra. Pa — papillae, Ci — cilia.

FIGURE 3. Pholoe microantennata sp. nov. — A. parapodia from anterior / median region, dorsal view; B. third parapodia, dorsal view; C, D. notopodia from anterior region; E. capillaries notochaeta; F, G. neurochaeta falcigers. S — stylodes, CA — ciliated area, SB — subdistal bractea, Sp — spinous chaeta.