Perinereis houbihuensis, Hsueh, 2024

Perinereis cultrifera ( Grube, 1840) View in CoL ( Fig. 3 View Fig , Table 2)

Nereis cultrifera Grube 1840: 76 View in CoL , fig. 6.

Perinereis cultrifera Hutchings et al. 1991: 253–254 View in CoL , fig. 8a–c; Park and Kim 2017: 255, figs. 4C, 5F.

Material examined: 19 specimens, NMNS 8748- 11–20, Fuguijiao (25°17.75'N, 121°31.99'E), habitat type: IRHB, 19 November 2003; 11 specimens, NMNS 8748 - 21 – 22, Fuguijiao (25 ° 17.75 ' N, 121°31.99'E), habitat type: IRHB, 12 March 2004; 16 specimens, NMNS 8748-23, Shimen (25°17.85'N, 121°34.14'E), habitat type: IRHB, 14 March 2004; 13 specimens, NMNS 8748-24–27, Shimen (25°17.85'N, 121°34.14'E), habitat type: IRHB, 17 March 2006; 10 specimens, NMNS 8748-28–32, Shimen (25°17.85'N, 121°34.14'E), habitat type: IRHB, 14–15 April 2007; 15 specimens, NMNS 8748-33–34, Wanlitong (21°59.73'N, 120°42.26'E), habitat type: IRHB, 14 December 2007; 13 specimens, NMNS 8748-35–39, Shimen (25°17.85'N, 121°34.14'E), habitat type: IRHB, 9–10 May 2008; 6 specimens, NMNS 8748-40–42, Jihuei (23°06.87'N, 121°24.21'E), habitat type: IRHB, 7–9 October 2010; 1 specimen, NMNS 8748-43, Jihuei (23°06.87'N, 121°24.21'E), habitat type: IRHB, 25 March 2011.

Description: Based on 10 complete specimens ( NMNS 8748-11–12, 14–15, 18, 24–25, 27(1); all atoke) and two incomplete specimens ( NMNS 8748- 13–17; all atoke): Body length 23.0–58.0 (n = 10) mm with 71–96 (n = 10) chaetigers, chaetiger 10 width 1.5– 3.7 (n = 12) mm, excluding parapodia; beige in alcohol ( Fig. 3A, B 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 3–8 (n = 12). Two pairs of eyes, in trapezoidal arrangement. Tentacular belt about 1.2–1.4x (n = 12) longer than chaetiger 1. Pharynx with dark brown jaws, each with 5–7 (n = 12) teeth; paragnath pattern: I = 1–6 (mostly 4–5, one case of 1, 3 and 6) (n = 12, same sample size on following areas), in cluster; II = 14–25 (left), 13–20 (right), in 2–3 oblique rows; III = 13–29 (center region with 12–24 cones, in 3–4 transverse rows; mostly 2 lateral regions, each with 1–4 or 0–3 cones); IV = 18–29 (left), 14–30 (right), in 3–4 oblique rows; V = 1–4 (mostly 3, one case of 1, 2 and 4); VI = 1 (left), 1 (right), short bars; VII –VIII = 22–37, in 2 rows. Ridge pattern of areas VI – V – VI, λ-shaped ( Fig. 3A, B View Fig , Table 2).

Dorsal cirri digitiform, medially attached dorsal ligule throughout, about 0.6x as long as dorsal ligule on anterior to mid-body chaetigers, about 0.4x as long as dorsal ligule on posterior chaetigers ( Fig. 3C–E View Fig , Table 2).

Dorsal ligule subconical throughout, about 1.4x longer than median ligule on anterior chaetigers, about 1.8–2.0x longer than median ligule on mid-body to posterior chaetigers; central and proximal lobes of dorsal ligule with one glandular mass throughout ( Fig. 3C–E View Fig , Table 2). Notopodial prechaetal lobe present on anterior to anterior-most of mid-body chaetigers ( Fig. 3C, D View Fig , Table 2).

Median ligule subconical throughout, about as long as neuroacicular ligule throughout ( Fig. 3C–E View Fig ).

Neuroacicular ligule with predominant inferior lobe on anterior chaetigers, about as long as ventral ligule throughout, inferior and superior lobes subequal in length on mid-body to posterior chaetigers. 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 on anterior to mid-body chaetigers, about 0.9x as long as ventral ligule on mid-body chaetigers to posterior chaetigers ( Fig. 3C–E 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. 3F–G View Fig , Table 2).

Pygidium with anus crenulated; anal cirri cirriform, as long as last 2–4 (n = 6) chaetigers ( Table 2).

Distribution: Mediterranean Sea, English Channel ( Hutchings et al. 1991); Taiwan.

Remarks: Park and Kim (2017) reported that P. cultrifera reported by Izuka (1912) and Wu (1967) from Taiwan are all actually P. euiini Park and Kim, 2017 . This practice makes the presence record of P. cultrifera in Taiwan no longer valid. However, material of the present study suggests that P. cultrifera does exist in Taiwan. Paragnath pattern and morphology of parapodia and chaetae of present specimens ( Fig. 3B, C– G View Fig , Table 2) agree mostly with syntypes of P. cultrifera examined by Hutchings et al. (1991: 253, fig. 8a–c) and Park and Kim (2017: 255–256, 258, figs. 3A, 4A– C, 5A1, 2, 5F, table 4), including several key characters (i.e., the presence of lateral teeth on area III, central and proximal lobes of dorsal ligule with one glandular mass on all chaetigers, the presence of prechaetal lobe on anterior chaetigers, and not greatly expanded dorsal ligule on posterior chaetigers). Figure 4 View Fig in Park and Kim (2017: 255) showed that P. cultrifera has λ-shaped ridge pattern of areas VI – V – VI, which is the same as the present specimens ( Fig. 3A View Fig ). Nevertheless, minor morphological discrepancies between the present specimens and above-mentioned descriptions have been noted in the present study. For example, number of paragnaths on areas I and III in the present specimens have a range of 1–9 with mostly 4–5 and 13–29, respectively, whereas that of is 1–2 and 5–11 or 10–12, respectively ( Table 2, Hutchings et al. 1991: 253; Park and Kim 2017: 258, table 4). Collection and habitat information of present specimens indicate this species is widespread on rocky coasts in Taiwan.

Perinereis cultrifera View in CoL is originally described from the Mediterranean Sea and later reported from most temperate oceans ( Grube 1840; Hutchings et al. 1991). However, taxonomic confusions from work of Fauvel (1932) leads to the suggestion by Hutchings et al. (1991) that additional distribution records of the species from other geographic regions, such as Marshall Islands, New Caledonia, India, South Africa and Madagascar, Japan, require verification. Park and Kim (2017: 256, fig. 6) suggested that all P. cultrifera View in CoL reported from East China, Korea, Japan, and Taiwan are actually P. euiini View in CoL . In the present study, the author follows the distribution range reported in Hutchings et al. (1991) and adds a verified additional location of the species from Taiwan.

Perinereis daxiensis sp. nov. ( Fig. 4 View Fig , Table 3) urn:lsid:zoobank.org:act:E2B163CF-3B53-4156-A7CF-2F6DBE69796B

Material examined: Holotype, NMNS 8748-44 View Materials , Daxi (24°56.59'N, 121°54.23'E), habitat type: IRHB, 25 April 2000. GoogleMaps

Etymology: The name is derived from the name of nearby village, Daxi, where the worm was collected.

Description: Holotype, atoke, complete, body length 110.0 mm with 128 chaetigers, chaetiger 10 width 3.6 mm, excluding parapodia; beige in alcohol ( Fig. 4A 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 5. Two pairs of eyes, in trapezoidal arrangement. Tentacular belt about 1.4x longer than chaetiger 1. Pharynx with dark brown jaws, each with 5 teeth; paragnath pattern: I = 2, in longitudinal line; II = 9 (left), 10 (right), in cluster; III = 16 (center region with 14 cones, in oval-shaped patch; 2 lateral regions, each with 1 cone); IV = 22 (left), 23 (right), in 3 oblique rows, without bars; V = 1; VI = 9 (left), 10 (right), even length short bars in transverse row; VII –VIII = 23, in 2–3 rows. Ridge pattern of areas VI – V – VI, λ-shaped ( Fig. 4B View Fig , Table 3).

Dorsal cirri digitiform, attached 1/3 to base of dorsal ligule, about 0.7x as long as dorsal ligule on anterior chaetigers, attached 1/4–1/5 to base of dorsal ligule on mid-body to posterior chaetigers, about 0.8x as long as dorsal ligule on mid-body chaetigers, about 0.6x as long as dorsal ligule on posterior chaetigers ( Fig. 4C–E View Fig , Table 3).

Dorsal ligule subconical throughout, about 2.0x longer than median ligule on anterior chaetigers, about 1.2–1.4x longer than median ligule on mid-body to posterior chaetigers; center lobe of dorsal ligule with one round glandular mass on posterior chaetigers ( Fig. 4E View Fig , Table 3). Notopodial prechaetal lobe absent ( Table 3).

Median ligule subconical throughout, longer than neuroacicular ligule throughout ( Fig. 4C–E View Fig ).

Neuroacicular ligule with subequal inferior and superior lobes, about 0.4–0.5x as long as ventral ligule throughout. 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 on anterior chaetigers, about 0.5x as long as ventral ligule on mid-body chaetigers to posterior chaetigers ( Fig. 4C–E 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: medium-sized blade heterogomph falcigers with serrations present throughout ( Fig. 4F View Fig , Table 3), heterogomph spinigers absent ( Table 3).

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

Type locality: Daxi, Yilan County, Taiwan.

Distribution: Known only from type locality.

Remarks: Perinereis daxiensis sp. nov. has an arc of 9–10 bar-shaped paragnaths on area VI of the pharynx and not greatly expanded notopodial dorsal ligule on posterior chaetigers, which can be categorized to the group 3A proposed by Hutchings et al. (1991: 271) ( Fig. 4B View Fig , Table 3). Likewise, members of the 3A group are also belonging to the Perinereis nuntia species group ( Hutchings et al. 1991: 273; see the species group diagnosis in Wilson and Glasby 1993: 259; Glasby and Hsieh 2006: 558; Villalobos-Guerrero 2019: 468). Of the 20 known species of the Perinereis nuntia group recognized by Villalobos-Guerrero (2019: 490), only P. weijhouensis Wu, Sun and Yang, 1981 is similar to P. daxiensis sp. nov. Both species have: 1) dorsal ligule not elongated and of similar size in all parapodia, notopodial prechaetal and neuropodial postchaetal lobes not developed; 2) area II with paragnaths, area III with lateral paragnaths, area V with less than 5 paragnaths, area VI with single arc of paragnaths, areas VII –VIII with less than 199 paragnaths; and 3) neuropodial heterogomph spinigers absent on chaetigers of all body regions ( Fig. 4B–F View Fig , Table 3; Wu et al. 1981: 181–182, fig. 114A–B, G). However, P. daxiensis sp. nov. differs from P. weijhouensis by having: 1) greater number of paragnaths on areas II, IV, and VI (9–10, 22–23, and 9–10 versus 4–6, 12–18, and 4–8, respectively) and fewer number of paragnaths on areas VII –VIII (23 versus 39); 2) area VI paragnaths in semicircular-shaped and tightly aligned without gaps (versus rectangular and loosely aligned with gaps between paragnaths); 3) dorsal cirri shorter than dorsal ligule on posterior chaetigers (versus longer than dorsal ligule); and 4) one round glandular mass in the center lobe of dorsal ligule on posterior chaetigers (versus absent) ( Fig. 4B–F View Fig , Table 3; Wu et al. 1981: 181–182, fig. 114A–B, G). The differences between P. daxiensis sp. nov. and the other new species of the 3A group described in the present study are discussed below.