Clymenura scutata Tovar-Hernandez and Yanez-Rivera , 2020,

Yanez-Rivera, Beatriz, Tovar-Hernandez, Maria Ana, Galvan-Villa, Cristian Moises & Rios-Jara, Eduardo, 2020, Tubicolous polychaete worms (Annelida) from Bahia de Chamela Islands Sanctuary, Mexico, with the description of a new bamboo worm, Biodiversity Data Journal 8, pp. 57572-57572 : 57572

Clymenura scutata Tovar-Hernandez and Yanez-Rivera, 2020 sp. n.

Materials

Type status: Holotype. Occurrence: catalogNumber: LEMA-PO153 ; recordedBy: Beatriz Yáñez-Rivera; lifeStage: Adult; Taxon: phylum: Annelida; class: Polychaeta; family: Maldanidae; genus: Clymenura; Location: higherGeographyID: Pacific Ocean; higherGeography: Tropical Eastern Pacific; continent: America; islandGroup: Islas de Chamela; island: Isla Cocinas; country: México; countryCode: MX; stateProvince: Jalisco; municipality: La Huerta; maximumDepthInMeters: 7; verbatimLatitude: 19°32 ’57’’ N; verbatimLongitude: 105°06 ’20’’ W; Identification: identifiedBy: María Ana Tovar-Hernández; Event: samplingProtocol: Scuba dive; eventDate: June 27, 2013; year: 2013; month: 6; day: 27; habitat: On rock; fieldNumber: Site 16; Record Level: language: Spanish; institutionID: Universidad de Guadalajara; collectionID: Colección Biológica del Laboratorio de Ecosistemas Marinos y Acuicultura, Universidad de Guadalajara, México; institutionCode: UDG; collectionCode: LEMA Type status: Paratype. Occurrence: catalogNumber: UANL 8144 ; recordedBy: Beatriz Yáñez-Rivera; individualCount: 3; lifeStage: Adult; Taxon: phylum: Annelida; class: Polychaeta; family: Maldanidae; genus: Clymenura; Location: higherGeographyID: Pacific Ocean; higherGeography: Tropical Eastern Pacific; continent: America; islandGroup: Islas de Chamela; island: Isla Cocinas; country: México; countryCode: MX; stateProvince: Jalisco; municipality: La Huerta; maximumDepthInMeters: 7; verbatimLatitude: 19°32 ’57’’ N; verbatimLongitude: 105°06 ’20’’ W; Identification: identifiedBy: María Ana Tovar-Hernández; Event: samplingProtocol: Scuba dive; eventDate: June 27, 2013; year: 2013; month: 6; day: 27; habitat: On rock; fieldNumber: Site 16; Record Level: language: Spanish; institutionID: Universidad Autónoma de Nuevo León; collectionID: UANL, NL INV 0002-05-09; institutionCode: UANL; collectionCode: UANL Type status: Paratype. Occurrence: catalogNumber: ICML-EMU-12758 ; recordedBy: Beatriz Yáñez-Rivera; individualCount: 1; lifeStage: Adult; Taxon: phylum: Annelida; class: Polychaeta; family: Maldanidae; genus: Clymenura; Location: higherGeographyID: Pacific Ocean; higherGeography: Tropical Eastern Pacific; continent: America; islandGroup: Islas de Chamela; island: Isla Cocinas; country: México; countryCode: MX; stateProvince: Jalisco; municipality: La Huerta; maximumDepthInMeters: 8; verbatimLatitude: 19°33 ’07’’ N; verbatimLongitude: 105°06 ’31’’ W; Identification: identifiedBy: María Ana Tovar-Hernández; Event: samplingProtocol: Dredge; eventDate: June 27, 2013; year: 2013; month: 6; day: 27; habitat: On rock; fieldNumber: Site 14; Record Level: language: Spanish; institutionID: Universidad Nacional Autónoma de México, Instituto de Ciencias del Mar y Limnología; collectionID: Colección Regional de Invertebrados Marinos; institutionCode: UNAM-ICML; collectionCode: ICML-EMU

Description

Preserved holotype complete, with body pale without any distinctive pigmentation pattern (Fig. 2 A). Body 32 mm length (complete paratypes: 28 mm in paratype 2 (UANL-8144), 20 mm in paratype 4 (ICML-EMU-12758); incomplete paratypes: 28 mm in paratype 1 (UANL-8144), 10 mm in paratype 3 (UANL-8144); 1 mm width (1 mm in paratypes 2 (UANL-8144) and 4 (ICML-EMU-12758); 0.5 mm in paratype 2 (UANL-8144), 0.8 mm in paratype 3 (UANL-8144). Body with 14 chaetigers (complete paratypes: 20 chaetigers in paratype 2 (UANL-8144); 15 chaetigers in paratype 4 (ICML-EMU-12758), two preanal achaetigerous segments with tori (two preanal achaetigers segments in all paratypes, except in paratype 1 (UANL-8144) whose posterior end is missing). Well-developed cephalic plaque, oval, with lateral margins smooth, entire (no incisions or notches) (Fig. 2 B-C) and posterior margin V-shaped (Fig. 2 C). Nuchal organs straight, parallel, almost full length of plaque (Fig. 2 C). Palpode well developed with rounded tip (Fig. 2 C). No ocelli. No segmental collars (Fig. 2 A, Fig. 3 A). Ventral shield of chaetiger 8 half-oval shaped, revealed with methyl green (Fig. 3 A-B). Chaetigers 11 and 12 are the longest (paratype 1, UANL-8144: chaetigers 10 and 11; paratype 2, UANL-8144: chaetigers 13-15). Notochaetae capillaries of one type, smooth by only slightly winged (Fig. 3E); those from anterior segments short (Fig. 3 F), whereas those from posterior chaetigers as long was two times the length of capillaries from anterior segments (Fig. 3 G). Single row of manubriavicular uncini present, starting in chaetiger 1 with 3-4 small teeth above the main fang, subrostral bristles or hairs or barbules not seen (Fig. 3 C) and long and nearly straight handles. Manubriavicular uncini from median and posterior chaetigers similar shape to those present in chaetiger 1, but with developed subrostral bristles or hairs or barbules (Fig. 3 D) and handles curved. First and second preanal segments about 1/2 and 2/3 length of last chaetigerous segment, respectively, with achaetous reduced torus (Fig. 2 A-B). Pygidial funnel well developed (Fig. 2 D-F), ending with 28 distinct triangular cirri (26-29 in paratypes), well separated and alternated short with long (twice longer than short ones) and with the ventral cirrus long (about twice the length of the long alternates) (Fig. 2 A-B). Pygidial funnel with a distinctive callus ring (Fig. 2 A). Anus terminal, located just in the centre of the funnel (Fig. 2 F). Glandular pattern revealed with methyl green shows blue bands in anterior segments (Fig. 3 A) and glandular shield on chaetiger 8 stains deep blue (Fig. 3 B).

Diagnosis

A worm of 32 mm length, 1 mm width, with 14 chaetigers, two pre-anal achaetous segments with tori, manubriavicular uncini present from chaetiger 1 with 3-4 teeth above the main fang without barbules; manubriavicular uncini similar to that of chaetiger 1, but the number of barbules increases towards the most posterior segments. Cephalic plaque oval with entire, smooth margins; rounded palpode; nuchal organs straight, parallel, almost full length of plaque. No ocelli, no segmental collars. Anal funnel present with 28 distinct alternating triangular cirri: short and long (twice longer than short ones) and with the mid-ventral cirrus longest (about twice the length of the adjacent long). Chaetiger 8 glandular shield extending anteriorly and ventrally from notochaetal fascicle forming a half-oval.

Etymology

From the Latin scutata , meaning armed with a shield and referring to the glandular shield on chaetiger 8.

Taxon discussion

The specimens, here reviewed, match with the emendation of Clymenura provided by Read (2011). The genus Clymenura has never been reported in Mexico. The closest record to the Mexican Pacific of a Clymenura is C. gracilis Hartman, 1969 ( Hartman 1969), a species originally described from Santa Monica, California. However, Read (2011) considers C. gracilis as incertae sedis because the holotype lacks of ventral shield on chaetiger 8; consequently, it cannot be a member of Clymenura .

Amongst the nine valid taxa of Clymenura worldwide, two species have been described from America: C. cirrata (Ehlers, 1887 as Clymene ) ( Ehlers 1887) from Florida and C. columbiana (Berkeley, 1929 as Leichone ) ( Berkeley 1929) to western Canada (Table 2 ). Clymenura scutata sp. n., and C. columbiana have an anal plaque with a long mid-ventral cirrus; however, Clymenura scutata sp. n. differs from C. columbiana by:

lateral margins of the cephalic plaque are entire,

does not present prostomial ocelli,

it has a marked dentition of uncini in first thoracic chaetiger and

it has two preanal achaetous segments (cephalic plaque notched laterally, prostomial eyes present, reduced or reminiscent dentition of uncini in first thoracic chaetiger and three pre-anal achaetous segments in C. columbiana ).

Clymenura cirrata is characterised by the presence of four long anal cirri (only the mid-ventral is long in Clymenura scutata sp. n.); the lateral margins or the cephalic plaque are notched (entire in Clymenura scutata sp. n.); and collars are present in chaetigers 2-4 (absent in Clymenura scutata sp. n.).

The rest of the species in the genus were described from high north European latitudes and the Northern Pacific region: Novaya Zemlya (one species), Japan (three species), Norway (one species), the Laptev Sea (one species), except for Clymenura snaiko Read, 2011 ( Read 2011), that was described from New Zealand (see Read 2011 to further details). Clymenura snaiko and Clymenura scutata sp. n., have the mid-ventral anal cirrus long, but the Mexican species have alternated cirri, whereas all other cirri are similar in length in C. snaiko . In addition, the lateral margins of the cephalic plaque are notched in C. snaiko versus entire in C. scutata sp. n.

Referring to intraspecific variation, a paratype was found under regeneration of the anterior end of the body (Fig. 2 G). The cephalic plaque and the first three segments are a half narrower than segment 4 and those subsequent. However, the glandular shield on chaetiger 8 is present, it maintain the half-oval shape. As the number of chaetigers (and size) varies in all paratypes, their use, therefore, cannot be considered diagnostic.

Figures

Figure 2. Clymenura scutata sp. n. A) Entire worm, lateral view, tube removed, B-C) cephalic plaque, latero-dorsal views, D-E) posterior end and anal plaque, lateral and ventral view, respectively, F) anal plaque, posterior view, G) worm regenerating cephalic plaque and first anterior segments. A-D, F) Holotype LEMA-PO 153, E, G) Paratype UANL 8144. Scale bars: A) 2 mm, B-E, G) 1 mm, F) 0.6 mm.

Figure 3. Clymenura scutata sp. n. A) Worm with cephalic plaque and first three chaetigers under regeneration, B) glandular shield in chaetiger 8, C) manubriavicular uncini from 1 st chaetiger, D) manubriavicular uncinus from 11 chaetiger, E) notochaetae from 11 chaetiger, F) third chaetiger, G) last chaetiger. A, G) Paratype UANL 8144, B-F) Holotype LEMA-PO 153. Scale bars: A-B) 1 mm, C-E) 1000 X magnification, F-G) 0.5 mm.