Perinereis tubicola, Hsueh, 2024

Perinereis vancaurica ( Ehlers, 1868) View in CoL ( Fig. 22A–R View Fig )

Nereis vancaurica Ehlers 1868 View in CoL : XX; Ehlers 1904: 25 (replacement name for N. languida Grube, 1867 View in CoL ). Nereis languida View in CoL — Grube 1867: 15, pl. 2, fig. l. Nereis (Perinereis) vancaurica View in CoL — Grube 1878: 83–84. Nereis (Perinereis) nancaurica Augener 1922: 23 View in CoL . Perinereis horsti Gravier 1901: 182 View in CoL , figs. 182–184, pl. l, fig. 47. Perinereis nancaurica Monro 1931a: 14 View in CoL ; Monro 1931b: 38–41, fig.

2a–f. Perinereis vancaurica Fauvel 1932: 103 View in CoL ; Kott 1951: 88, l11; Fauvel

1932: 103; Fauvel 1953: 205–206, fig. 105f–g; Russell 1962: 7;

Day 1967: 334, fig. 14.12k–o; Wu 1967: 70–71; Wu et al. 1981:

176–177, fig. 111A–J; Wu et al. 1985: 195–197, fig. 111A–J;

Hartmann-Schroder 1979: 117, figs. 207–210; Hutchings et al.

1991: 265–266, fig. 17a–h. Perinereis vancaurica indica Bhatt and Bal 1966: 25 . Perinereis linea Wu 1967: 68–69 , fig. 10a–d, non Treadwell 1936. Perinereis vancaurica tetradentata Imajima 1972: 86–88 , fig. 23a–i.

Material examined: 2 specimens, NSNM 8748- 136, Fuguijiao (25°17.75'N, 121°31.99'E), habitat type: IRHB, 12 March 2004; 3 specimens, NSNM 8748- 137–139, Linshanbi (25°16.99'N, 121°30.59'E), habitat type: IRHB, 14 Mach 2004; 8 specimens, NSNM 8748- 140–147, Shimen (25°17.85'N, 121°34.14'E), habitat type: IRHB, 3–4 November 2007; 31 specimens, NSNM 8748 - 148 – 178, Shimen (25 ° 17.85 ' N, 121°34.14'E), habitat type: IRHB, 9–11 May 2008; 2 specimens, NSNM 8748-179–180, Shimen (25°17.85'N, 121°34.14'E), habitat type: IRHB, 22 November 2010.

Description: Based on 12 complete specimens (NSNM 8748-137–139, NSNM 8748-148, NSNM 8748-152, NSNM 8748-156–157, NSNM 8748-163, NSNM 8748-175, NSNM 8748-177–179; all atoke) and

33 incomplete specimens (NSNM 8748-136, NSNM 8748-140–147, NSNM 8748-149–151, NSNM 8748- 153–155, NSNM 8748-158–162, NSNM 8748-164– 174, NSNM 8748-176, NSNM 8748-180; all atoke): Body length 40.5–100.0 (n = 12) mm with 109–195 (n = 12) chaetigers, chaetiger 10 width 1.2–3.5 (n = 45) mm, excluding parapodia; beige in alcohol ( Fig. 22A–L View Fig ). Prostomium wider than long, lateral antennae antero-lateral, shorter than palps, palpophores globose, palpostyles spheroid. Four pairs of tentacular cirri, longest one reaching chaetiger 1–5 (mostly 2, one case of 1 or 5, 3 cases of 3 and five cases of 4, n = 45). Two pairs of eyes, in trapezoidal arrangement. Tentacular belt about 1.1–1.4x (n = 45) longer than chaetiger 1. Pharynx with dark brown jaws, each without teeth; paragnath pattern: I = 0–6 (mostly 2, few cases of 3 and 4, one case of 0 and 6, n = 45, same sample size on following areas); II = 20–40 (left), 14–42 (right), in 2–4 oblique rows; III = 48–104 (center region with 27–66 cones, in oval cluster; mostly 2 lateral regions, each with 6–23 cones, in longitudinal lines with less 10 cones, in oval cluster with more than 10 cones, nine cases of 3 lateral groups, outer-most lateral group with 1–3 cones, two cases of 4 lateral groups, outer-most lateral groups each with 3–12 cones) ( Fig. 22E–K View Fig ); IV = 60–108 (left), 59–110 (right), in chevron-shaped; V = 3 (mostly 3, rare cases of 1 or 2), in shallow triangle (longitudinal line, transverse row or triangle); VI = 2 (mostly 2 even length bars, two cases of 2 uneven-length bars, one case of 2 long+1 short bars, one case of 2 long+2 short bars, two cases of 2 bars+1 cone) (left), 2 (mostly 2 even length bars; two cases of 2 uneven-length bars; two cases of even length 2 bars+1 cone) (right) ( Fig. 22A–D View Fig ); VII–VIII = 53–121, in 2 rows; anterior row 8–15 large cones interspaced with 15–79 small and medium cones in 1–3 lines ( Fig. 22E–K View Fig ), six cases of small and medium cones clustered around large cones in mid-ventral oral region, posterior row with 16– 37 large cones in zigzag arrangement ( Fig. 22L View Fig ). Ridge pattern of areas VI–V–VI, ɔc-shaped ( Fig. 22A–D View Fig ).

Dorsal cirri digitiform throughout, attached 1/3 to base of dorsal ligule on anterior chaetigers, about 0.3x as long as dorsal ligule, medially attached to dorsal ligule on mid-body to posterior chaetigers, about 0.5– 0.6x as long as dorsal ligule ( Fig. 22M–O View Fig ).

Dorsal ligule conical with blunt tip on anterior chaetigers, about 1.7x longer than median ligule, subconical on mid-body to posterior chaetigers, about 2.0–2.1x longer than median ligule ( Fig. 22M–O View Fig ). Notopodial prechaetal lobe absent.

Median ligule conical, round on anterior chaetigers, about as long as neuroacicular ligule, subconical on mid-body to posterior chaetigers, about as long as neuroacicular ligule ( Fig. 22M–O View Fig ).

Neuroacicular ligule with predominant inferior lobe on anterior chaetigers, inferior and superior lobes subequal in length on posterior half of mid-body to posterior chaetigers, about as long as ventral ligule. Neuropodial postchaetal lobe absent. Ventral ligule subconical throughout. Ventral cirri digitiform, mid-ventrally attached to ventral edge of parapodia, about 0.7x as long as ventral ligule throughout ( Fig. 22M–O View Fig ).

Notochaetae present from chaetiger 3 to posterior chaetigers, homogomph spinigers present throughout. Supra-acicular fascicle of neuropodia: homogomph spinigers and short-bladed heterogomph falcigers with serrations present throughout. Subacicular fascicle of neuropodia: short-bladed heterogomph falcigers with serrations and heterogomph spinigers present throughout ( Fig. 22P–R View Fig ).

Pygidium with anus crenulated; anal cirri cirriform, as long as last 2–6 (n = 13) chaetigers.

Distribution: Australia, East Asia, French Guiana (Atlantic Ocean), Gulf of Mexico, Indo-West Pacific Oceans, Red Sea ( Fauvel 1932 1953; Hutchings et al. 1991; Fauchald et al. 2009).

Remarks: Different descriptions of P. vancaurica ( Ehlers, 1868) in different reports causes considerable confusion for properly identifying this species. Grube (1867: 15, pl. 2, fig. 1a b) provided a brief description and an antero-dorsal view drawing of extruded pharynx of Nereis languida ( Grube, 1867) (type locality: Vancauri (= Nancowry Island), Nicobar Islands, Indian Ocean). Ehlers (1868: XX) noted Grube’s name was a junior homonym of N. languida Kinberg, 1865 and replaced the junior homonym by N. vancaurica ( Ehlers, 1868) without giving any description. He later gave a brief description on paragnath pattern of the species: area I with one cone, areas II and IV with double or triple cones in curved rows, area III with cones in transverse double rows, area V with three small cones in triangle, area VI with two large transverse linear ones, areas VII–VIII with cones in one transverse double rows ( Ehlers 1904: 25). Based on these two earlier descriptions, specimens with this type of paragnath patterns from many geographic regions in the Indo-West Pacific Oceans were referred to P. vancaurica regardless significant differences between these reports in paragnath patterns on areas III and VII–VIII of the pharynx. For instance, area III of type specimen has no lateral groups of cones ( Ehlers 1904: 25), but specimens of P. vancaurica collected from Singapore ( Fauvel 1953: 206, fig. 105g), Japan ( Imajima 1972: 86, fig. 23b), Southeast China ( Wu et al. 1981: 176, fig. 111B), and Taiwan ( Wu 1967: 71) have lateral groups of cones on the same area. However, Hutchings et al. (1991: 265–266, fig. 17c) redescribed P. vancaurica collected from Australia with no lateral groups of cones on area III. Moreover, some reports described the species with small cones interspaced with large cones on anterior row of area VII–VIII ( Fauvel 1953: 206, fig. 105g; Wu et al. 1981: 176, fig. 111B; Wu 1967: 71) but other reports indicated otherwise. For instance, Hutchings et al. (1991: 265–266, fig. 17c) described P. vancaurica collected from Australia with a large patch of small cones interspaced with large cones in mid-ventral region on the anterior row of area VII–VIII. Both P. linea ( Treadwell, 1936) in Wu (1967) and P. vancaurica tetradentata Imajima 1972 , which have been synonymized with P. vancaurica by Hutchings et al. (1991), have no small cones interspaced with large cones on anterior row of area VII–VIII ( Wu 1967: 71, fig. 10b; Imajima 1972: 86, fig. 23b).

The morphology of the present specimens agrees with the original description of P. vancaurica only on paragnath pattern of areas V and VI of the pharynx and morphology of parapodia ( Fig. 22A–D, M–O View Fig ; Grube 1867: 15, pl. 2, fig. 1a, b; Ehlers 1904: 25). The present specimens are more similar to specimens of this species collected from Singapore, Southeast China, and Taiwan than those from Australia and Indian Ocean in terms of paragnath patterns on areas III and VII–VIII of the pharynx ( Fig. 22E–K View Fig ; Grube 1867: 15, pl. 2, fig. 1a, b; Fauvel 1953: 206, fig. 105g; Wu 1967: 71; Wu et al. 1981: 176, fig. 111B; Hutchings et al. 1991: 266, fig. 17c). These significant differences in paragnath patterns between P. vancaurica from Southeast Asia and from Australia suggests that further examination using molecular analysis for the possible presence of cryptic species might be needed. The present study reports for the first time that Taiwanese specimens of P. vancaurica have a peculiar paragnath pattern on anterior row of areas VII–VIII. Six specimens of the present study have small and medium cones form several clusters around large cones in mid-ventral oral region on the anterior row of areas VII–VIII ( Fig. 22L View Fig ). However, these six specimens cannot be distinguished from other specimens of the same species examined in the present study besides the above-mentioned character. Lastly, a few specimens have one long bar and 2 short to medium length bars on each side of area VI ( Fig. 22B, D View Fig ). This abnormal paragnath pattern of area VI in these few individuals might be explained by breaking off of one long bar into two shorter bars on this pharyngeal area.

Perinereis wanlitongensis sp. nov. ( Fig. 23 View Fig , Table 4) urn:lsid:zoobank.org:act:3E5DAE6F-23F9-4A36-A028-5C6E77AEE040

Material examined: Holotype, NSNM 8748-181 ,

Wanlitong (21°59.73'N, 120°42.26'E), habitat type: IRHB, 15 May 2009. Paratypes: 1 specimen, NSNM 8748-182, collection date and location information same as holotype; 1 specimen, NSNM 8748-183, collection location information same as holotype, 15 Mach 2008.

Etymology: The name is derived from the name of nearby village, Wanlitong, where worms were collected.

Description: Based on holotype (NSNM 8748- 181, complete; atoke) and paratypes (NSNM 8748- 182–183, complete; all atoke): body length 64.0 (35.0–112.0, n = 2) mm with 115 (112–161, n = 2) chaetigers, chaetiger 10 width 1.5 (2.1) mm, excluding parapodia; beige in alcohol ( Fig. 23A View Fig ). Prostomium wider than long, lateral antennae antero-lateral, shorter than palps, palpophores globose, palpostyles spheroid. Four pairs of tentacular cirri, longest one reaching chaetiger 4 (3, n = 1). Two pairs of eyes, in trapezoidal arrangement. Tentacular belt about 1.3x longer than chaetiger 1. Pharynx with brown jaws, each with 5–6 (5, n = 2) teeth; paragnath pattern: I = 2 (2, n = 1, same sample size on following areas) uneven size cones, in longitudinal line, posterior cone larger; II = 12 (11) (left), 13 (13) (right), in cluster; III = 20 (20) (center region with 16 (16) cones, in cluster; 2 lateral regions, each with 2 (2) cones, in longitudinal line); IV = 24 (22) (left), 27 (24) (right), in 3–4 oblique rows, without bars; V = 4 (3) uneven size cone, anterior 3 cones in triangle, largest cone anteriorly, smallest cone posteriorly; VI = 1 (1) (left), 1 (1) (right), smooth bars; VII–VIII = 30 (33), in 2–3 rows. Ridge pattern of areas VI–V–VI, λ-shaped ( Fig. 23B View Fig , Table 4).

Dorsal cirri digitiform, medially attached to dorsal ligule on anterior to mid-body chaetigers, about 0.8x as long as dorsal ligule, attached 4/5 to base of dorsal ligule on posterior chaetigers, about 0.3x as long as dorsal ligule on posterior chaetigers ( Fig. 23C, D View Fig , Table 4).

Dorsal ligule subconical throughout, about 1.9x longer than median ligule on anterior to mid-body chaetigers; base of dorsal ligule greatly elongated and broader on posterior chaetigers, about 4.2x longer than median ligule; distal, center and proximal lobes each with one irregular-shaped glandular mass on mid-body to posterior chaetigers ( Fig. 23C, D View Fig ). Notopodial prechaetal lobe absent ( Table 4).

Median ligule subconical throughout, about 1.3x longer than neuroacicular ligule on anterior chaetigers, about 1.8x longer than neuroacicular ligule on posterior chaetigers ( Fig. 23C, D View Fig ).

Neuroacicular ligule with predominant inferior lobe on anterior chaetigers, inferior and superior lobes subequal in length on posterior chaetigers, about 0.6x as long as ventral ligule on anterior to mid-body chaetigers, about as long as ventral ligule on posterior chaetigers. Neuropodial postchaetal lobe absent. Ventral ligule subconical throughout. Ventral cirri mid-ventrally attached to ventral edge of parapodia, about 0.6x as long as ventral ligule on anterior chaetigers, about 0.7x as long as ventral ligule on mid-body chaetigers, about as long as ventral ligule on posterior chaetigers ( Fig. 23C, D View Fig ).

Notochaetae present from chaetiger 3 to posterior chaetigers, homogomph spinigers present throughout. Supra-acicular fascicle of neuropodia: homogomph spinigers and short-bladed heterogomph falcigers with serrations present throughout. Subacicular fascicle of neuropodia: short-bladed heterogomph falcigers with serrations and heterogomph spinigers present throughout ( Fig. 23E, F View Fig , Table 4).

Pygidium with anus crenulated; anal cirri cirriform, as long as last 3–8 chaetigers.

Type locality: Wanlitong, Pingtung County, Taiwan.

Distribution: Known only from type locality.

Remarks: With one paragnath on area VI of the pharynx and greatly expanded dorsal ligule on posterior chaetigers, P. wanlitongensis sp. nov. is included in group 1B proposed by Hutchings et al. (1991: 271) ( Fig. 23B, D View Fig , Table 4). Of the six species in this group reported from East and Southeast Asia (see the Remarks section in P. kebalanae sp. nov. for the name of these six species), only P. malayana and P. nigropunctata are similar to P. wanlitongensis sp. nov. by having lateral paragnaths on area III, no bar-shaped paragnaths on area IV, and mostly 3 cones on area V ( Fig. 23B View Fig , Table 4; Horst 1889: 168, 172; Fauvel 1915: 7; Hutchings et al. 1991: 248, 250, 257–258, 263). However, P. wanlitongensis sp. nov. can be distinguished from P. malayana by having: 1) more paragnaths on area III (20 versus 14); 2) greater dorsal cirri to dorsal ligule length ratio on anterior and posterior chaetigers (about 0.8 and 0.3 versus 0.3 and 0.2 (based on measurements from pl. 8, fig. 4 in Horst 1889), respectively); 3) the distal, center and proximal lobes of dorsal ligule each with one irregular-shaped glandular masses on mid-body to posterior chaetigers (versus absent); and 4) anal opening not surrounded by papillae (versus surrounded by papillae) ( Fig. 23B–D View Fig , Table 4; Horst 1889: 168–170, pl. 8, figs. 4, 6).

Perinereis wanlitongensis sp. nov. differs from P. nigropunctata by having: 1) no prechaetal lobe on chaetigers of all body regions (versus present on chaetigers of all body regions); 2) greater length ratio of dorsal ligule to median ligule on posterior chaetigers (4.3 versus 3.3); and 3) one irregular-shaped glandular mass in each of the distal, center and proximal lobes of dorsal ligule on posterior chaetigers (versus 1 in the center lobe) ( Fig. 23C, D View Fig , Table 4).

Perinereis kebalanae sp. nov. and P. wanlitongensis sp. nov. are the two only new species described in the present study which can be categorized in group 1B ( Table 4). Perinereis kebalanae sp. nov. can be distinguished from P. wanlitongensis sp. nov. by having: 1) more paragnaths on areas II, III and IV (19–25, 30–35 and 50–54 versus 11–13, 20 and 22–27, respectively); 2) no lateral teeth on area III (versus present); 3) bar-shaped paragnaths on area IV (versus absent); 4) fewer number of paragnaths on area V (1 versus 3–4); 5) u-shaped ridge pattern of areas VI–V– VI (versus λ-shaped ridge pattern), no glandular masses in the lobes of dorsal ligule (versus 3 glandular masses); 6) smaller length ratio of dorsal ligule to median ligule on posterior chaetigers (3.5 versus 4.2); and 7) heterogomph spinigers on anterior chaetigers (versus absent on anterior chaetigers) ( Table 4).