Pista miosseci, Lavesque & Daffe & Londoño-Mesa & Hutchings, 2021

Lavesque, Nicolas, Daffe, Guillemine, Londoño-Mesa, Mario H. & Hutchings, Pat, 2021, Revision of the French Terebellidae sensu stricto (Annelida, Terebelliformia), with descriptions of nine new species, Zootaxa 5038 (1), pp. 1-63 : 44-46

publication ID	https://doi.org/ 10.11646/zootaxa.5038.1.1
publication LSID	lsid:zoobank.org:pub:1C1E4C7A-2452-47BC-B843-2543135EF780
persistent identifier	https://treatment.plazi.org/id/9D380527-7733-4C1D-B42E-9CB34E449D86
taxon LSID	lsid:zoobank.org:act:9D380527-7733-4C1D-B42E-9CB34E449D86
treatment provided by	Plazi
scientific name	Pista miosseci
status	sp. nov.

Treatment

Pista miosseci View in CoL n. sp.

Figure 20 View FIGURE 20

Material examined. Holotype. MNHN-IA-TYPE 2033, posteriorly incomplete (posterior part used for molecular analysis), Northeastern Atlantic , Bay of Biscay, Bay of Brest, VC, 48°18’59”N 4°23’28”W, depth 2.2 m, February 2019 GoogleMaps . Paratypes. AM W.53330, posteriorly incomplete (posterior part used for molecular analysis), Northeastern Atlantic , Bay of Biscay , Bay of Brest , VC, 48°18’59”N 4°23’28”W, depth 2.2 m, May 2018. MNHN-IA-TYPE 2034, posteriorly incomplete, Northeastern Atlantic , Bay of Biscay, Bay of Brest, VC, 48°18’59”N 4°23’28”W, depth 2.2 m, October 2015, mounted for GoogleMaps SEM.

Description. In life, yellowish body, with buccal tentacles translucent; posterior areas of neuropodia dark red as posterior margin of ventral shields ( Fig. 20A View FIGURE 20 ).

Holotype posteriorly incomplete, 16.8 mm long (14.2–36.0 mm) and 1.7 mm wide (1.9–2.8 mm), for 38 segments. Transverse prostomium attached to dorsal surface of upper lip; basal part with isolated eyespots, laterally covered by lobes on SG I and dorsally by prostomium (difficult to see); distal part of prostomium shelf-like. Buccal tentacles deeply grooved ( Fig. 20A–D View FIGURE 20 ). Peristomium forming lips, upper lip hood-like, large, wider than long, and circular; lower lip large and swollen, rectangular, wider than long ( Fig. 20D View FIGURE 20 ).

Segment I long, without lateral lobes; connected ventrally by a thin and smooth (crenulated) membrane with rounded ventral indentation, surrounding lower lip ( Fig. 20A–D View FIGURE 20 ). Segment II with pair of rounded ventro-lateral lobes, connected to each other by a large mid-ventral crest, indented and crenulated ventrally. Segment III with pair of developed lateral lobes, larger than those of SG II, rounded, almost semi-circular lobes, connected to each other by a thin mid-ventral crest, ventrally crenulated (indented). Segment IV with pair of very short latero-dorsal rounded lobes, almost inconspicuous ( Fig. 20A–D View FIGURE 20 ).

Dorsal anterior margins of SG III–VIII as protruding crests ( Fig. 20B View FIGURE 20 ). Two pairs of dorso-lateral plume-shaped branchiae present on SG II–III, about the same size (or second pair smaller), first pair inserted more dorsally; each branchia with annulated basal stem, branches arranged in spiral with few dichotomies, branchial filaments long ( Fig. 20B–D View FIGURE 20 ). Smooth to corrugated mid-ventral shields present on SG IV–XVII, rectangular (squared) shields, of uniform width anteriorly, and becoming progressively longer posteriorly ( Fig. 20D View FIGURE 20 ).

Notopodia beginning on SG IV, extending until SG XX; notopodia short, rectangular, first four pairs inserted progressively more laterally, then longitudinally aligned ( Fig. 20A–C View FIGURE 20 ). Broadly-winged notochaetae arranged in two rows, broader on one side ( Fig. 20E View FIGURE 20 ), with first row shorter.

Neuropodia present from SG V, as low, almost sessile ridges until end of notopodia ( Fig. 20A–C View FIGURE 20 ), as low rectangular pinnules thereafter. Neurochaetae as long-handled uncini on SG V–X ( Fig. 20F–G View FIGURE 20 ), with well-developed handles originating from heel. Uncini arranged in partially intercalated double rows on SG XI–XX; in a face-toface arrangement. Uncini avicular, with short, triangular heel, distally rounded prow, pointed dorsal button inserted halfway between base of main fang and prow, convex base, and main fang surmounted by crest with five rows of numerous, progressively shorter secondary teeth ( Fig. 20F–H View FIGURE 20 ).

Genital papillae on SG VI–VII, globular, situated dorsally behind notopodia ( Fig. 20B View FIGURE 20 ).

Pygidium unknown.

Etymology. This species is dedicated to the famous Brest singer Christophe Miossec, whose music has accompanied NL for 25 years, especially when writing. This name was chosen in agreement with Jacques Grall and Vincent Le Garrec from the IUEM Brest laboratory who provided the type material.

Habitat. Shallow waters (depth 2 m), in maërl (rhodolith) beds.

Type locality. Bay of Brest , Bay of Biscay, Northeastern Atlantic Ocean, France. 48°18’59”N 4°23’28”W GoogleMaps .

Distribution. Only known from the type locality.

Remarks. With two pairs of branchiae, P. miosseci n. sp. belongs to the Pista cristata ( Müller, 1776) complex. Pista miosseci n. sp. differs from this last species by the presence of eyespots, the presence of dorsal crests on SG III–VIII and the presence of long-handled uncini on SG X. Pista miosseci n. sp. does not have lateral lobes on SG I while those of P. cristata are short and SG IV with pair of very short latero-dorsal rounded lobes while they are well-developed for P. cristata . However, investigations should be done concerning the presence of the dorsal crests, as they could be dependent on fixation.

Among the other European Pista species with this two pairs of branchiae, P. miosseci n. sp. differs from P. mediterranea by the absence of lateral lobes on SG I instead of presence of short ones for P. mediterranea . P. miosseci n. sp. differs also from P. mediterranea by the shape of thoracic uncini. Indeed, P. mediterranea has very high uncini on SG V, with a vertical prow and anterior comma-shaped uncini extension that are absent in P. miosseci n. sp. The comma-shaped uncini extension is a robust part of the uncini but its observation depends on the angle of the final preparation of the microscope slide. Thus, several uncini should be observed to confirm this character.

Pista miosseci n. sp. differs from P. sauriaui n. sp. by the absence of anterior comma-shaped extension on thoracic uncini that are present for P. sauriaui n. sp. and by the presence of long-handled uncini on SG X that are restricted to the SGV–VII for P. sauriaui n. sp. Pista miosseci n. sp. does not have lateral lobes on SG I while those of P. sauriaui n. sp. are large. Finally, P. miosseci n. sp. has eyespots which are absent in P. sauriaui n. sp.

Finally, Pista miosseci n. sp. differs from P. wui Saphronova, 1988 by the absence of large lobes on SG I (instead of small ones) and very short lateral lobes on SG IV, instead of well-developed ones for P. wui and by the presence of dorsal crests and eyespots which are absent on P. wui . The presence of dorsal crests may depend on fixation of specimens. Moreover, these crests were not considered a valuable taxonomic character until recently, and may be present in several species but have not been described.

In European waters, two other species of Pista with two pairs of branchiae, but with invalid status, occur: Terebella turrita Grube, 1860 , synonymised with P. cristata ( Fauvel 1927; Hartman 1959) and Pista malmgreni Saphronova & Jirkov in Jirkov, 2001 synonymised with P. mediterranea (see above). With a type locality situated in Adriatic Sea, T. turrita is probably valid under the genus Pista , belonging to the P. cristata complex. However, it is not possible to reinstate this species based on the original description and further investigations should be conducted.