Notomastus mazatlanensis García-Garza & León-González & Tovar-Hernández 2019, sp. nov.
Creators: name: García-Garza, María Elena
name: León-González, Jesús Angel De
name: Tovar-Hernández, María Ana
Publisher: name: Zenodo
Year: 2019
Subjects: Biodiversity
Taxonomy
Animalia
Annelida
Polychaeta
Capitellida
Capitellidae
Notomastus
Notomastus mazatlanensis

description: 43. Notomastus mazatlanensis sp. nov.
(Fig. 6 a–e)
Material examined. Holotype (UANL-8128) Eastern Pacific, Mexico, Southern Gulf of California, Sinaloa, Mazatlán, Marina Mazatlán, 23°16’2.1”N, 106°27’14.5”W, September 5, 2018, 6 m, mud. (4) Paratypes (UANL- 8129), October 11, 2015, Colls. MEG-G, MAT-H and JAL-G. Comparative material examined. Notomastus hemipodus Hartman, 1945: Holotype (LACM-AHF Poly 414), Paratypes (4) (LACM-AHF Poly 415), (1) (LACM- AHF Poly 2667), (2) (LACM-AHF Poly 2668); (6) (LACM-AHF Poly 2669). Notomastus fauvelii Day, 1955: Holotype (BMNH 1961.16.73-74).
Diagnosis. Prostomium conical with palpode and eyespots. Thorax with an achaetous peristomium and 11 chaetigers with capillary chaetae. First chaetiger uniramous. Abdominal segments with hooded hooks in both rami. Branchiae present dorsally. Pygidium without appendages.
Description. Holotype incomplete, fragmented in 4 parts, anterior fragment with 50 segments, 22.2 mm long, 0.89 mm wide, and 38 segments, 14.8 mm long, 0.86 mm wide; posterior fragments with 43 segments, 15.5 mm long, 1.2 mm wide, and 68 segments, 38.0 mm long, 1.4 mm wide. Paratypes incomplete, 50–89 segments, 22–66 mm long, 1.4 mm wide. Color in ethanol reddish-white. Prostomium conical with palpode. Eyespots covered by peristomium, small, forming discrete groups on both sides of prostomium. Proboscis everted, globular, finely papillated. Peristomium and chaetigers 1-3 with tessellated epithelium; following thoracic segments smooth (Fig. 6a).
Thorax with 11 chaetigers armed with bi-limbated capillary chaetae. First chaetiger uniramous. Thoracic chaetigers biannulated. Notopodia inserted laterally in first fifth thoracic chaetigers, then notopodia inserted dorsally from chaetiger 6 to posterior thorax (Fig. 6a). Lateral organs occurring from first thoracic chaetiger (Fig. 6a) towards abdominal segments, between noto- and neuropodia, but closer to notopodia; abdominal lateral organs as small protuberances, closer to notopodial lobes (Fig. 6b). Genital pores located at chaetigers 8–11, under neuropodial lobes.
Transition between thorax and abdomen marked abruptly by size of segments. Abdominal segments with smooth epithelium. Abdominal neuropodia with hooded hooks throughout. Abdominal notopodia widely separated dorsally, without lobe, with hooded hooks on both rami (six hooks per fascicle) (Fig. 6b). Neuropodial lobes ventrally separated, with 28–30 hooded hooks per fascicle (Fig. 6e). Digitiform, eversible branchia emerging from body wall on medial abdominal segments and so on towards posterior end; branchiae aligned below the notopodia bearing 3–4 branchial filaments initially (Fig. 6c) and 28–30 in posterior segments (Fig. 6d). Hooded hooks similar in shape on noto- and neuropodia; long anterior shaft, angulated node, evident constriction, posterior shaft longer than anterior one, developed shoulder, covered with numerous apical filaments; with a main fang and four rows of small teeth, basal row with three teeth, intermediary row with 4–5 teeth and distal, one with an indeterminate number (Fig. 6f). Pygidium without appendages.
Methyl green staining pattern. Prostomium, peristomium and chaetigers 1 and 2 stained light green; chaetigers 3 and 4 with moderate green, and chaetigers 5–11 dark green (Fig. 6a). Anterior abdominal segments stained dark green dorsally (Fig. 6b). Posterior abdominal segments stained dark green, with a dotted band around each segment (Fig. 6c, e).
Remarks. Notomastus mazatlanensis sp. nov., is similar to N. fauvelii and N. hemipodus by having finger-like branchiae emerging from the epithelium near the notopodia. However, N. mazatlanensis sp. nov. differs from N. fauvelii by presenting the first chaetiger uniramous and the digitiform branchiae grouped in 3–4 filaments in anterior abdominal segments, while N. fauvelii has the first chaetiger biramous (Fig. 4a) and the branchiae are composed by 15 filaments in anterior abdominal segments (Fig. 6h). Furthermore, glandular staining pattern is markedly different in N. fauvelii: peristomium, segments 6–9 and post-chaetal area of segment 11 stain moderate green; abdominal segments have two pre and post-chaetal longitudinal bands dark green running along, and each abdominal segment present narrow, transversal bands dark green (Fig. 4a).
Notomastus mazatlanensis sp. nov. and N. hemipodus present the first chaetiger uniramous, but both species differ in that N. mazatlanensis sp. nov. has 3–4 branchial filaments per notopodium, while N. hemipodus presents bilobed branchiae (Fig. 6g). In addition, the glandular staining pattern of N. hemipodus is very evident in the abdominal segments, presenting moderate green marks, and ventral region with a pair of longitudinal bands toward the end of the body.
Etymology. The specific name is related to the type locality where the new species was found: Mazatlán, in a marina located in the Southern Gulf of California, México (Fig. 1).
description: Published as part of García-Garza, María Elena, León-González, Jesús Angel De & Tovar-Hernández, María Ana, 2019, Catalogue of Notomastus M. Sars, 1851 (Annelida, Capitellidae) and the description of a new species from the Gulf of California, pp. 249-273 in Zootaxa 4577 (2) on pages 262-263, DOI: 10.11646/zootaxa.4577.2.2, http://zenodo.org/record/2629701