Brevicirrosyllis paulolanai, Fukuda & Paiva, 2024

Rodolfo Leandro Nascimento, Marcelo Veronesi Fukuda & Paulo Cesar de Paiva, 2024, Two new incertae sedis syllids (Annelida: Syllidae) from Brazilian oceanic islands, European Journal of Taxonomy 925 (1), pp. 46-66 : 51-53

Brevicirrosyllis paulolanai sp. nov.

urn:lsid:zoobank.org:act:6AFB0EF7-ECB4-43F5-AE89-43DA78943CA5

Fig. 1

Differential diagnosis

Brevicirrosyllis without dorsal cirri on chaetiger 2, parapodial glands absent, palps similar in length to prostomium, median antenna more than four times as long as palps, dorsal peristomial cirri longer than body width.

Etymology

This species is named in honor of the late Dr Paulo da Cunha Lana (20 April 1956 – 30 June 2022), a remarkable Brazilian researcher who left an indelible mark in the fields of oceanography, marine ecology, and systematics of marine invertebrates, especially polychaetes. Throughout his distinguished career, Dr Lana inspired and amazed generations of researchers with his unwavering passion for science and his deep love for people. He once expressed that while he loved polychaetes, he loved people even more. Dr Lana’s invaluable contributions to the scientific community and his steady commitment to excellence in research make him an outstanding role model and a true inspiration. We are deeply grateful for his legacy. Thank you, Paulo.

Type material

Holotype

BRAZIL • Trindade Island, Enseada da cachoeira ; 20.2357136° S, 28.6968285° W; depth 18 m; 4 Jul. 2012; MZUSP 6096 .

Paratype

BRAZIL • 1 spec.; Trindade Island, Ilha da Racha ; 20.5083781° S, 29.4587883° W; depth 21 m; 16 Jul. 2013; MZUSP 6097 .

Description

Medium to long-sized body, slender, longest specimen examined incomplete, 7 mm long, 0.17 mm wide, with 47 chaetigers; body without pigmentation in specimen preserved in ethanol ( Fig. 1A ). Palps triangular, distally tapering, fused only at bases, about same length of prostomium; prostomium subpentagonal, with a pair of eyes close to bases of lateral antennae, and a pair of eyespots on anterior margin; lateral antennae inserted slightly anteriorly to pair of eyes, about same length of palps; median antenna inserted posteriorly to eyes, on middle of prostomium or slightly posteriorly, almost four times as long as lateral ones, basally smooth, distal half rugose ( Fig. 1A ). Peristomium distinct, shorter than subsequent segments; dorsal peristomial cirri about same length of palps and prostomium together, longer than body width and lateral antennae, but shorter than dorsal cirri from chaetiger 1; ventral peristomial cirri almost ½ length of dorsal ones ( Fig. 1A ). Dorsal cirri from chaetiger 1 longer than remaining ones, with almost half length of median antenna; dorsal cirri absent on chaetiger 2; remaining dorsal cirri digitiform to distally slightly tapered, without internal glands, longer than parapodial lobes but shorter than width of respective chaetiger, approximately ½–¾ length of median antenna ( Fig. 1A ). Ventral cirri digitiform, shorter than parapodial lobes. Parapodial lobes conical.Anterior body parapodia with 5–4 falcigers each, 4–3 falcigers on midbody and 3 falcigers on each posterior body parapodium; shafts of falcigers hemigomph, smooth, thicker ventralwards; blades bidentate, distal tooth slightly larger than subdistal one throughout; on each anterior parapodium, dorsalmost blade elongate, subdistally faintly sinuous ( Fig. 1B ); blades with short and thin spines on margin, with smooth connective joining blade and shafts on anterior and midbody parapodia; blades with dorsoventral gradation in length, about 27–10 µm on anterior body ( Fig. 1B ), 29–8 µm on midbody ( Fig. 1C ) and 15–7 µm on posterior body parapodia ( Fig. 1E ). Dorsal simple chaetae present from chaetiger 10–11, truncated, with few spines laterally, becoming slightly thicker towards posterior body ( Fig. 1F–H ). Ventral simple chaetae not observed, possibly lost with the posteriormost segments. One acicula per parapodium throughout almost bent at right angle, with irregular, tapering tip ( Fig. 1D ). Pharynx through 2.5–3 segments; with conical to rhomboidal pharyngeal tooth located on anterior rim ( Fig. 1A ). Proventricle through 2.5 segments, with 32–30 muscle cell rows.

Remarks

Brevicirrosyllis paulolanai sp. nov. is distinguished from its congeners by several morphological features, including palps of approximately the same length as the prostomium, median antenna more than four times as long as palps, and dorsal peristomial cirri with similar length to that of the palps and prostomium combined, which is greater than the body width. The dorsal cirri of chaetiger 1 are longer than those of the remaining chaetigers, about half the length of the median antenna or twice the width of the corresponding segment, while the dorsal cirri of the remaining chaetigers are shorter, digitiform to slightly tapered distally, and lack internal glands.

The species Brevicirrosyllis ancori , originally described from the Pacific Ocean off Queensland, Australia, shares many similarities with the newly described B. paulolanai sp. nov., including overall body morphology (palps, body wall, and appendages) and shape of compound chaetae ( Table 1 ). However, several distinct differences set B. ancori apart, including palps that are about 1.5 times as long as the prostomium, a shorter median antenna that is only about twice the length of the palps, and dorsal peristomial cirri about the same size as the palps and roughly equivalent to the body width ( Table 1 ). Additionally, B. ancori possesses parapodial glands ( Table 1 ). San Martín & Hutchings (2006) noted some variation in B. ancori , such as the occasional presence of two pairs of eyes, longer dorsal cirri on chaetiger 1, and larger parapodial glands than in the holotype, and despite these variations, B. paulolanai is readily distinguishable from B. ancori .

Type locality

Trindade Island, Espírito Santo, Brazil.

Distribution

South Atlantic Ocean, Trindade Island.

Figures

Fig. 1. Brevicirrosyllis paulolanai sp. nov., holotype (MZUSP 6096). A. Anterior body, dorsal view. B–C, E. Falciger chaetae, anterior, mid- and posterior body, respectively. D. Acicula. F–H. Dorsal simple chaetae, anterior, mid- and posterior body, respectively. Scale bars: A = 0.17 mm; B–H = 10 µm.