Perinereis fugangensis, Hsueh, 2024

Perinereis floridana ( Ehlers, 1868) View in CoL ( Fig. 5 View Fig , Table 2)

Nereis floridana Ehlers 1868: 503–506 View in CoL .

Perinereis floridana Monro 1933: 256 View in CoL ; Salazar-Vallejo and Jiménez-Cueto 1996 –1997: 367, figs. 8, 32, 33; de León-González and Solís-Weiss 1998: 684, figs. 6A–E, 7A–E; Chen et al. 2002: 17– 29; Fauchald et al. 2009: 771; de León-González and Goethel 2013: 7.

Material examined: 4 specimens, NSNM 8748- 44–48, Wuchi Harbor (24°17.61'N, 120°31.18'E), habitat type: SRHB, 7 July 2015; 4 specimens, NSNM 8748-49–52, Wuchi (24°17.61'N, 120°31.18'E), habitat type: SRHB, 5 October 2015.

Description: Based on 4 complete specimens ( NSNM 8748 - 45, 47, 49 – 50; all atoke) and 4 incomplete specimens ( NSNM 8748-46, 48, 51–52; all atoke): Body length 35.0–93.0 (n = 4) mm with 71–96 (n = 4) chaetigers, chaetiger 10 width 2.0–4.0 (n = 8) mm, excluding parapodia; beige in alcohol ( Fig. 5A 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 2–3 (n = 7). Two pairs of eyes, in trapezoidal arrangement. Tentacular belt about 1.1–1.4x (n = 7) longer than chaetiger 1. Pharynx with dark brown jaws, each with 5–8 (n = 8) teeth; paragnath pattern: I = 1–3 (mostly 1, one case of 2 (in longitudinal line) and 3 (in triangle), n = 8, same sample size on following areas); II = 9–13 (left), 9–12 (right), in 2–3 oblique rows; III = 9–15 (mostly without lateral teeth, two cases of 1 lateral teeth on one side), in oval-shaped patch; IV = 15–23 (left), 15–23 (right), in 3–4 oblique rows, without bars; V = 0–1 (mostly 1, one case of 0); VI = 0–1 short bar (mostly 1, one case of 0) + 0–4 cones (mostly 0 cones, one case of 4 cones) (left), 1 short bar (right); VII –VIII = 27–38, in 2 rows. Ridge pattern of areas VI – V – VI, λ-shaped ( Fig. 5A–D View Fig , Table 2).

Dorsal cirri digitiform, attached 1/3 to base of dorsal ligule, about 0.8x as long as dorsal ligule on anterior to mid-body chaetigers, attached 2/3 to base of dorsal ligule on posterior chaetigers, about 0.4x as long as dorsal ligule ( Fig. 5E–G View Fig , Table 2).

Dorsal ligule subconical throughout, about 1.7– 2.0x longer than median ligule on anterior to mid-body chaetigers, about 2.2x longer than median ligule on posterior chaetigers ( Fig. 5E–G View Fig ). Notopodial prechaetal lobe Absent ( Table 2).

Median ligule subconical throughout, about as long as neuroacicular ligule on anterior chaetigers, about 1.7–1.8x longer than neuroacicular ligule on mid-body to posterior chaetigers ( Fig. 5E–G View Fig ).

Neuroacicular ligule with prominent inferior lobe on anterior to mid-body chaetigers, about 0.6x as long as ventral ligule, inferior and superior lobes subequal in length on posterior chaetigers, about 0.5x 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 on anterior chaetigers, about 0.8x as long as ventral ligule on mid-body chaetigers to posterior chaetigers ( Fig. 5E–G 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 and heterogomph spinigers present throughout ( Fig. 5H View Fig , Table 2).

Pygidium with anus crenulated; anal cirri cirriform, as long as last 4–5 (n = 6) chaetigers ( Table 2).

Distribution: Gulf of Mexico, Caribbean Sea, Quintana Roo ( Mexico) ( de León-González and Solís-Weiss 1998), Red Sea ( Gravier 1901); South China Sea ( Glasby et al. 2016), western and northern Taiwan.

Remarks: Morphology of examined specimens in the present study agrees mostly with description of P. floridana ( Ehlers, 1868) in de León-González and Solís-Weiss (1998: 684 , figs. 6A–E) ( Fig. 5A–H View Fig , Table 2). Although the type of ridge pattern of areas VI – V – VI was not available in the text, de León-González and Solís-Weiss (1998) did draw a pharynx everted epitoke form of the species which is clearly with λ-shaped ridge pattern of areas VI – V – VI ( de León-González and Solís-Weiss 1998: 686, fig. 7A). The present specimens also have the same type ridge pattern of areas VI – V – VI ( Fig. 5A, C View Fig , Table 2). However, there are some morphology discrepancies between the present specimens and the above-mentioned description. For example, one of present specimens has cones and bars on area VI of the pharynx, and this variation was not observed by de León-González and Solís-Weiss (1998: 684) ( Fig. 5C View Fig ). Moreover, dorsal ligule on posterior chaetigers of the present specimens has greater dorsal ligule to median ligule ratio (2.2 versus 1.6) on posterior chaetigers than that of described in de León-González and Solís-Weiss (1998: 684–685, fig. 6D) ( Fig. 5C View Fig , Table 2). The presence of cone on area VI of P. floridana collected from the Red Sea was also observed by Gravier (1901: 186, text-fig. 188). Moreover, Gravier (1901: 186, text-figs. 188–189) noted that specimens of P. floridana from the Red Sea has 1 to 3 paragnaths on area V, in comparing to that of 0 to 1 and 1 in specimens of the present study and de León-González and Solís-Weiss (1998: 684), respectively. All examined specimens of P. floridana in the present study have been collected from subtidal fouling community on cement surfaces of piers in Wuchi Harbor (central-west Taiwan) and Bisha Harbor (northern Taiwan).

Perinereis floridana View in CoL is somewhat similar to P. helleri ( Grube, 1878) View in CoL , but it can be distinguished from the latter species by having: 1) the longest tentacular cirri reaching chaetigers 2–3 (versus chaetiger 16); 2) no lateral teeth on area III (versus presence of lateral teeth); and 3) greater ratio of dorsal ligule to median ligule on posterior chaetigers (2.2x versus 1.4x) ( Fig. 5A, C, G View Fig , Table 2; Hutchings et al. 1991: 255, fig. 9b). Perinereis floridana View in CoL is also somewhat similar to P. obfuscata ( Grube, 1878) View in CoL , but the former species differs from the latter species by having: 1) the longest tentacular cirri reaching chaetigers 2–3 (versus chaetiger 1); 2) no lateral teeth on area III (versus presence of lateral teeth); and 3) greater ratio of dorsal ligule to median ligule on posterior chaetigers (2.2x versus 1.9x) ( Fig. 5A, C, G View Fig , Table 2; Hutchings et al. 1991: 258, fig. 11b).

Perinereis fugangensis sp. nov. ( Figs. 6 View Fig , 7 View Fig ) urn:lsid:zoobank.org:act:F112629E-329A-48C5-BB68-4F3C19DFE2C3

Material examined: Holotype, NSNM 8748-53 , Fugang (22°47.63'N, 121°11.89'E), habitat type: IRHB, 15 October 2004. GoogleMaps

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

Description: Holotype, atoke, complete, body length 236.0 mm with 521 chaetigers, chaetiger 10 width 2.6 mm, excluding parapodia; body beige in alcohol ( Fig. 6A View Fig ). Prostomium wider than long, lateral antennae antero-lateral, longer than palps, palpophores globose, palpostyles spheroid. Four pairs of tentacular cirri, longest one reaching chaetiger 1. Two pairs of eyes, in trapezoidal arrangement. Tentacular belt about 1.3x longer than chaetiger 1. Pharynx with dark brown jaws, each without teeth; paragnath pattern: I = 0; II = 0; III = many minute cones in wide band; IV = many minute cones in wide band, without bars; V = 10 scattered small cones + many minute cones in wide band; VI = 20 (left), 21 (right), even length short bars in transverse row + many minute cones in wide band posteriorly; VII –VIII = numerous minute cones in wide band. Ridge pattern of areas VI – V – VI, u-shaped ( Fig. 6B–E View Fig ).

Dorsal cirri digitiform, medially attached to dorsal ligule, about 0.4–0.6x as long as dorsal ligule on anterior chaetigers, attached 2/3 to base of dorsal ligule, about 0.3x as long as dorsal ligule on posterior-half of anterior to mid-body chaetigers, subdistally attached to dorsal ligule on posterior chaetigers, distally attached to dorsal ligule, about 0.1x as long as dorsal ligule on posterior-most chaetigers ( Fig. 7A–E View Fig ).

Dorsal ligule subconical throughout, distal lobe of dorsal ligule greatly reduced in size on posterior-half of anterior to posterior chaetigers; expansion of dorsal ligule commenced at chaetiger 395, gradually increased thereafter, about 3.7x longer than median ligule at chaetiger 507 and thereafter ( Fig. 7A–E View Fig ). Notopodial prechaetal lobe present on posterior-half of anterior chaetigers to end of posterior chaetigers ( Fig. 7B–E View Fig ).

Median ligule conical throughout, about 2.0x longer than neuroacicular ligule ( Fig. 7A–E View Fig ).

Neuroacicular ligule with subequal inferior and superior lobes, about as long as ventral ligule throughout. Neuropodial postchaetal lobe absent. Ventral ligule subconical throughout. Ventral cirri 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, about 0.3x as long as ventral ligule on posterior chaetigers ( Fig. 7A–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 present throughout, heterogomph spinigers present on posterior-half of anterior to posterior chaetigers ( Fig. 7F View Fig ).

Pygidium with anus crenulated; anal cirri cirriform, as long as last 1 chaetiger.

Type locality: Fugang, Taitung City, Taiwan.

Distribution: Known only from type locality.

Remarks: Perinereis fugangensis sp. nov. has 20–21 bar-shaped paragnaths on area VI of the pharynx and greatly expanded notopodial dorsal ligule on posterior chaetigers, which can be categorized in group 3B proposed by Hutchings et al. (1991: 271) ( Figs. 6B View Fig , 7E View Fig ). This group of Perinereis has been represented by a single species, P. maindroni Fauvel, 1943 (type locality: Pondicherry (now known as Puducherry), India). Perinereis fugangensis sp. nov. can be easily distinguished from P. maindroni by paragnath patterns and notopodial morphology. Perinereis fugangensis sp. nov. has no paragnaths on area II (versus few cones in crescentic rows), many minute cones in a wide band on area IV (versus few in arcs), 10 scattered small cones and many minute cones in a wide band on area V (versus no paragnaths), 20 to 21 short bars and many minute cones in a wide band posteriorly on area VI (versus 5 to 6 short bars), and numerous minute cones on areas VII –VIII (versus 3 rows of cones) ( Fig. 6B–E View Fig ; Fauvel 1943: 201). The expansion of dorsal ligule in P. fugangensis sp. nov. begins on posterior chaetigers, but that of P. maindroni starts on mid-body chaetigers ( Fig. 7E View Fig ; Fauvel 1943: 201, fig. 1h–i). Moreover, the expansion region of dorsal ligule on posterior chaetigers in P. fugangensis sp. nov. is the proximal lobe of dorsal ligule, whereas that of region of P. maindroni is the distal lobe of dorsal ligule ( Fig. 7E View Fig ; Fauvel 1943: 201, fig. 1h–i).

Of the known congeners, P. fugangensis sp. nov., in fact, is rather similar to P. neocaledonica Pruvot, 1930 (type locality: New Caledonia), a member of the group 3A, in terms of paragnath patterns and parapodial morphology of posterior chaetigers ( Hutchings et al. 1991). Both species have no paragnaths on areas I and II, many minute cones in a wide band on areas III and IV, many minute cones in a wide band posteriorly on areas V and VI, and numerous minutes cones in a wide band on areas VII –VIII ( Pruvot 1930: 53, pl. III, fig. 77–79). Moreover, both species have greatly expanded dorsal ligule on posterior chaetigers ( Fig. 7E View Fig ; Pruvot 1930: 51, fig. IVb). However, Hutchings et al. (1991: 273) and Wilson and Glasby (1993: 262) suggested P. neocaledonica is a junior synonym of P. caeruleis (Hoagland, 1920) , which has no greatly expanded dorsal ligule on posterior chaetigers and has been categorized in group 3A. Due to the above-mentioned authors had examined only non-type material of P. caeruleis . The author herein treats P. neocaledonica as a valid species. In fact, Pruvot (1930: 54) commented that the type specimen of P. caeruleis is incomplete posteriorly and cannot be ascertain of its parapodial morphology on posterior chaetigers. On the contrary, P. neocaledonica is known to have greatly elongated dorsal ligule on posterior chaetigers ( Pruvot 1930: 51–52, fig. IVb). With this evidence, P. neocaledonica should belong in group 3B. Despite morphological similarities between the two species, P. fugangensis sp. nov. can be distinguished from P. neocaledonica by having: 1) 10 small and many minute cones scattered on area V (versus one large and many minute cones); 2) short bars on area VI (versus cones); 3) smaller length ratio of expanded dorsal ligule to median ligule on posterior chaetigers (about 3.7 versus about 5.2 (based on the measurement from the drawing of fig. IVb in Pruvot 1930)); and 4) one elongated rectangle glandular mass in each of the center and proximal lobes of dorsal ligule on posterior chaetigers (versus one elongated rectangle glandular mass) ( Figs. 6B, C, E View Fig , 7E View Fig ; Pruvot 1930: 51–54, fig. IVb, pl. III, figs. 77–79).

It is worth mentioning that there are some morphological discrepancies between P. neocaledonica reported by Wu (1967) and the type by Pruvot (1930) in several aspects. Wu (1967: 74, fig. 12d) showed that the length ratio of dorsal ligule to median ligule on posterior chaetiger is only about 3.2, whereas that of ratio in the type is about 5.2 ( Pruvot 1930: 51, fig. IVb). Moreover, Wu (1967: 73) stated that P. neocaledonica has neuropodial heterogomph spinigers present only on posterior chaetigers, but Pruvot (1930: 52) acknowledged the presence of neuropodial heterogomph spinigers at the beginning of middle third of the body segments to posterior chaetigers.

Perinereis houbihuensis sp. nov. ( Fig. 8 View Fig , Table 2) urn:lsid:zoobank.org:act:98CAF5A1-D840-4902-9628-30579ED51AAB

Material examined: Holotype, NSNM 8748-54 , Houbihu Harbor (21°56.32'N, 120°44.73'E), habitat type: SRHB, 19 November 2010. GoogleMaps

Etymology: The name is derived from the name of Houbihu Harbor, where the worm was collected.

Description: Holotype, atoke, complete, body length 74.5 mm with 72 chaetigers, chaetiger 10 width 2.5 mm, excluding parapodia; beige in alcohol ( Fig. 8A, 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 2. Two pairs of eyes, in trapezoidal arrangement. Tentacular belt longer than chaetiger 1. Pharynx with dark brown jaws, each with 5 teeth; paragnath pattern: I = 2 uneven size cones, in longitudinal line, larger cone with square base, located posteriorly; II = 11 (left), 12 (right), in 3 oblique rows; III = 19, in oval-shaped patch, without lateral teeth; IV = 16 (left), 12 (right), in 3 oblique rows, without bars; V = 1; VI = 1 (left), 1 (right), short bars; VII –VIII = 33, in 2 rows. Ridge pattern of areas VI – V – VI, χ-shaped ( Fig. 8A, B View Fig , Table 2).

Dorsal cirri digitiform with base bulged, attached 1/3 to base of dorsal ligule, about 0.5x as long as dorsal ligule on anterior chaetigers, medially attached to dorsal ligule, about 0.5x as long as dorsal ligule on mid-body to posterior chaetigers ( Fig. 8C–E View Fig , Table 2).

Dorsal ligule conical on anterior chaetigers, about 1.8x longer than median ligule, subconical on mid-body to posterior chaetigers, about 2.3–2.5x longer than median ligule; center and proximal lobes of dorsal ligule each with one irregular-shaped glandular mass on posterior chaetigers ( Fig. 8E, G, I View Fig , Table 2). Notopodial prechaetal lobe present throughout ( Fig. 8C–F, I View Fig , Table 2).

Median ligule with truncated tip on anterior chaetigers, as long as neuroacicular ligule, subconical on mid-body chaetigers, about 2.0x longer than neuroacicular ligule on mid-body chaetigers, about 2.0x long than neuroacicular ligule on posterior chaetigers ( Fig. 8C–E View Fig ).

Neuroacicular ligule with subequal inferior and superior lobes throughout, about as long as ventral ligule on anterior to mid-body chaetigers, about 0.8x as long as ventral ligule on posterior chaetigers. Neuropodial postchaetal lobe absent. Ventral ligule conical on anterior chaetigers, subconical on mid-body to posterior chaetigers. Ventral cirri mid-ventrally attached to ventral edge of parapodia, about as long as ventral ligule throughout ( Fig. 8C–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; some abnormal posterior chaetigers with only one simple chaeta and losing both heterogomph falcigers and heterogomph spinigers ( Fig. 8I View Fig ). Subacicular fascicle of neuropodia: short-bladed heterogomph falcigers with serrations present throughout, heterogomph spinigers present only on posterior chaetigers ( Fig. 8F–H, J, K View Fig , Table 2); some abnormal posterior chaetigers losing both heterogomph falcigers and heterogomph spinigers ( Fig. 8I View Fig ).

Pygidium with anus crenulated; anal cirri cirriform, as long as last 3 chaetigers ( Table 2).

Type locality: Houbihu Harbor, Pingtung County, Taiwan.

Distribution: Known only from type locality.

Remarks: Perinereis houbihuensis sp. nov. has one bar-shaped paragnath on area VI of the pharynx and not greatly expanded notopodial dorsal ligule on posterior chaetigers, which would include it in group 1A proposed by Hutchings et al. (1991: 271) ( Fig. 8A, E View Fig ). Seven species in this group were reported from East and Southeast Asia, which are: Perinereis calmani (Monro, 1926) , P. cultrifera ( Grube, 1840) , P. dongalae ( Horst, 1924) , P. euiini Park and Kim, 2017 , P. floridana ( Ehlers, 1868) , P. helleri ( Grube, 1878) , and P. tenuisetis ( Fauvel, 1915) ( Wu 1967; Imajima 1972; Wu et al. 1981 1985; Sun and Yang 2004; Glasby et al. 2016; Park and Kim 2017). Of these seven species, only P. floridana has the similar paragnath patterns as P. houbihuensis sp. nov. on areas I, III, V and VI (2, 1, 19 without lateral teeth, and 1 versus 2, 1, 16 without lateral teeth and 1, respectively) ( de León-González and Solís-Weiss 1998: 684). However, P. houbihuensis sp. nov. can be distinguished from P. floridana by having: 1) χ-shaped ridge pattern on areas V – VI – V (versus λ-shaped ridge pattern); 2) notopodial prechaetal lobe present on chaetigers of all body regions (versus absent); 3) the center and proximal lobes of dorsal ligule each with one irregular-shaped glandular mass on posterior chaetigers (versus absent); and 4) neuropodial heterogomph spinigers present only on posterior chaetigers (versus present on chaetigers of all body regions) ( Fig. 8B, C, E, H View Fig , Table 2; de León-González and Solís-Weiss 1998: 684–685, fig. 6B–E).

Hutchings et al. (1991: 255) suggested that the length ratio of dorsal cirri to dorsal ligule is not an reliable character for species identification in the 1A group of the genus and has not been used herein for comparing differences between congers. The differences between P. houbihuensis sp. nov. and four other new species of the 1A group described in the present study are discussed below.

Perinereis hsinchuensis sp. nov. ( Fig. 9 View Fig , Table 3) urn:lsid:zoobank.org:act:E71CE585-7333-457B-91F1-A5A306582487

Material examined: Holotype, NSNM 8748-55 , Hsinchu Harbor (24°51.00'N, 120°55.48'E), habitat type: SRHB, 1 September 2019. GoogleMaps

Etymology: The name is derived from the Hsinchu Harbor, where the worm was collected.

Description: Holotype, atoke, without posterior end, remaining body length 23.5 mm with 59 chaetigers, chaetiger 10 width 1.2 mm, excluding parapodia; beige in alcohol ( Fig. 9A–C 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 2. Two pairs of eyes, in trapezoidal arrangement. Tentacular belt about 1.4x longer than chaetiger 1. Pharynx with dark brown jaws, each with 6 teeth; paragnath pattern: I = 3 large cones, in longitudinal line; II = 16 (left), 17 (right), in 2–3 oblique rows; III = 21 (center region with 17 cones, in oval-shaped patch; 2 lateral regions, each with 1 or 3 cones); IV = 26 (left), 30 (right), in 4–5 oblique rows, without bars; V = 3, in triangle; VI = 3 (left), 3 (right), uneven-length smooth bars in transverse row; VII –VIII = 37, in 2 rows. Ridge pattern of areas VI – V – VI, χ-shaped ( Fig. 9B and C View Fig , Table 3).

Dorsal cirri digitiform, medially attached to base of dorsal ligule, about 0.7x as long as dorsal ligule on anterior chaetigers, attached 1/3 to base of dorsal ligule on mid-body chaetigers, about 0.8x as long as dorsal ligule, attached 2/3 to base of dorsal ligule on posterior chaetigers, about 0.5x as long as dorsal ligule ( Fig. 9D– F View Fig , Table 3).

Dorsal ligule subconical throughout, about 2.4x longer than median ligule on anterior chaetigers, about 1.9–2.0x longer than median ligule on mid-body to posterior chaetigers; center lobe of dorsal ligule with one round glandular mass on posterior chaetigers ( Fig. 9D–F View Fig , Table 3). Notopodial prechaetal lobe absent ( Table 3).

Median ligule subconical throughout, about as long as neuroacicular ligule on anterior to mid-body chaetigers, about 1.8x longer than neuroacicular ligule on posterior chaetigers ( Fig. 9D–F View Fig ).

Neuroacicular ligule with subequal inferior and superior lobes, as long as ventral ligule throughout. Neuropodial postchaetal lobe absent. Ventral ligule subconical throughout. Ventral cirri mid-ventrally attached to ventral edge of parapodia, as long as ventral ligule on anterior to mid-body chaetigers, about 1.2x longer than ventral ligule on posterior chaetigers ( Fig. 9D–F View Fig ).

Notochaetae present from chaetiger 3 to posterior chaetigers, homogomph spinigers present throughout. Supra-acicular fascicle of neuropodia: homogomph spinigers and medium-sized blade heterogomph falcigers with serrations present throughout ( Fig. 9G, H View Fig , Table 3). Subacicular fascicle of neuropodia: medium-size blade heterogomph falcigers with serrations present throughout, heterogomph spinigers present only on anterior to mid-body chaetigers ( Fig. 9G, H View Fig , Table 3).

Type locality: Hsinchu Harbor, Hsinchu City, Taiwan.

Distribution: Known only from type locality.

Remarks: Perinereis hsinchuensis sp. nov. has an arc of three bar-shaped paragnaths on each side of area VI of the pharynx and not greatly expanded notopodial dorsal ligule on posterior chaetigers, which include it in group 3A, as well as the Perinereis nuntia species group ( Fig. 9B, F View Fig ; Hutchings et al. 1991: 271; Wilson and Glasby 1993: 259; Glasby and Hsieh 2006: 558; Villalobos-Guerrero 2019: 468). Of the 20 known species in this species group recognized by Villalobos-Guerrero (2019), only P. viridis Glasby and Hsieh, 2006 is similar to P. hsinchuensis sp. nov., because both species have uneven bar-shaped paragnaths and number of paragnaths ranging in 2–4 on area VI, and presence of lateral paragnaths on area III ( Fig. 9B, C View Fig , Table 3; Glasby and Hsieh 2006: 562, 569–570, fig. 9A–B, table 2; Villalobos-Guerrero 2019: 489). However, P. hsinchuensis sp. nov. differs from P. viridis in terms of having: 1) cones only on area IV (versus cones and bars), 2) three paragnaths on area V (versus one); 3)

ɔc-shaped ridge pattern of area areas VI – V – VI (versus χ-shaped ridge pattern); 4) dorsal cirri about 0.5x as long as dorsal ligule on posterior chaetigers (versus as long as dorsal ligule); 5) one round glandular mass in the center lobe of dorsal ligule on posterior chaetigers (versus one irregular-shaped glandular mass in each of the center and proximal lobes of dorsal ligule); and 6) neuropodia without heterogomph spinigers on posterior chaetigers (versus present throughout all body regions) ( Fig. 9B, C, F, H View Fig , Table 3; Glasby and Hsieh 2006: 562, 569–570, fig. 9A–D, table 2; Villalobos-Guerrero 2019: 489). The differences between P. hsinchuensis sp. nov. and eight other new species of the 3A group described in the present study are discussed below.

Perinereis kaomeiensis sp. nov. ( Fig. 10 View Fig , Table 3) urn:lsid:zoobank.org:act:FBF66483-C273-4161-972B-16B6C2233621

Material examined: Holotype, NMNS 3031-2 View Materials , Kaomei (24°18.50'N, 120°32.42'E), habitat type: ISSB, coll. S-M Chao, 2 November 1997. GoogleMaps

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

Description: Holotype, epitoke, complete, body length 98.0 mm with 180 chaetigers, chaetiger 10 width 5.0 mm, excluding parapodia; light brown in alcohol ( Fig. 10A, B View Fig ). Prostomium wider than long, lateral antennae antero-lateral, longer than palps, palpophores globose, palpostyles spheroid. Four pairs of tentacular cirri, longest one reaching chaetiger 8. Two pairs of eyes, in trapezoidal arrangement. Tentacular belt about 1.5x longer than chaetiger 1. Pharynx with dark brown jaws, each with 4 teeth; paragnath pattern: I = 9, in cluster; II = 17 (left), 18 (right), in 2 oblique rows; III = 54, in 5–6 transverse rows; IV = 22 (left), 25 (right), in 4–6 oblique rows, without bars; V = 5, in cluster; VI = 5 (left), 4 (right), even length short bars in transverse row; VII –VIII = 52, in 2–3 rows. Ridge pattern of areas VI – V – VI, ɔc-shaped ( Fig. 10A–C View Fig , Table 3).

Pre-natatory region: Dorsal cirri robust with filament distally on chaetiger 1 to 7, basally or medially attached to dorsal ligule, about 1.3x longer than dorsal ligule, digitiform on chaetiger 8 to 20, medially attached to dorsal ligule, about 0.8x as long as dorsal ligule. Dorsal ligule subconical. Notopodial prechaetal lobe present. Median ligule subconical. Neuroacicular ligule with predominant inferior lobe. Neuropodial postchaetal lobe absent. Ventral ligule subconical. Ventral cirri robust with filament distally on chaetiger 1 to 7, becoming digitiform from chaetiger 8 to 20, mid-ventrally attached to ventral edge of parapodia, about 0.8x as long as ventral ligule. Notochaetae homogomph spinigers. Supra-acicular fascicle of neuropodia: homogomph spinigers and long blade heterogomph falcigers with narrow serrations. Subacicular fascicle of neuropodia: homogomph spinigers and long blade heterogomph falcigers with narrow serrations ( Fig. 10D, J View Fig , Table 3).

Natatory region: Dorsal cirri digitiform, medially attached to dorsal ligule, about 0.6x as long as dorsal ligule; dorsal cirrus with small lobe presence from chaetiger 21, becoming large auricular lobe from chaetiger 24 to mid-body chaetigers, reduced progressively in size thereafter, absent on posterior half of posterior chaetigers. Dorsal ligule subconical. Notopodial prechaetal lobe absent. Median ligule subconical throughout, slightly longer than neuroacicular ligule, with small lobe close to base of dorsal surface on all natatory chaetigers, with irregular-shaped lobe at base of ventral surface on posterior-half of natatory chaetigers. Neuroacicular ligule with predominant inferior lobe, about as long as ventral ligule. Large neuropodial postchaetal lamella present on posterior-half of natatory chaetigers. Ventral ligule subconical, with small lobe close to base of dorsal surface throughout natatory chaetigers. Ventral cirri attached to base of parapodia, about 1.6x longer than ventral ligule with irregular-shaped dorsal and ventral lobes on anterior-half of natatory chaetigers, gradually reduced in size thereafter. Notochaetae homogomph spinigers absent, replaced by sesquigomph natatory chaetae. Supra-acicular fascicle of neuropodia: homogomph spinigers and heterogomph falcigers absent, replaced by sesquigomph natatory chaetae. Subacicular fascicle of neuropodia: homogomph spinigers and heterogomph falcigers absent, replaced by single sesquigomph natatory chaeta ( Fig. 10E, F, H, I, K View Fig , Table 3).

Post-natatory region: Dorsal cirri digitiform, medially attached to dorsal ligule, about 0.5x as long as dorsal ligule. Dorsal ligule subconical, not greatly expanded, about 2.1x longer than median ligule. Notopodial prechaetal lobe absent. Median ligule subconical, with small lobe close to base of dorsal surface on all chaetigers. Neuroacicular ligule with predominant inferior lobe, about as long as ventral ligule. Neuropodial postchaetal lobe absent. Ventral ligule subconical. Ventral cirri digitiform, with small irregular-shaped lobe on dorsal surface, shorter than ventral ligule. Notochaetae homogomph spinigers absent. Supra-acicular fascicle of neuropodia: homogomph spinigers and heterogomph falcigers absent. Subacicular fascicle of neuropodia: single heterogomph falciger and single homogomph spiniger present ( Fig. 10G, L, M View Fig , Table 3).

Pygidium with anus crenulated, opened dorsally, surrounded by papillae; anal cirri cirriform, as long as last 9 chaetigers ( Fig. 10N View Fig ).

Type locality: Kaomei tidal flat, Taichung City, Taiwan.

Distribution: Known only from type locality.

Remarks: With an arc of 4 – 5 bar-shaped paragnaths on area VI of the pharynx and not greatly expanded notopodial dorsal ligule on posterior chaetigers, P. kaomeiensis sp. nov. can be categorized in group 3A, together with Perinereis nuntia species group ( Fig. 10C, G View Fig , Table 3; Hutchings et al. 1991: 271; Wilson and Glasby 1993: 259; Glasby and Hsieh 2006: 558; Villalobos-Guerrero 2019: 468). Of the 20 species in this species group recognized by Villalobos-Guerrero (2019), only P. mictodonta ( Marenzeller, 1879) and P. nuntia (Lamarck, 1818) have paragnath patterns on areas V and VI that are somewhat similar to P. kaomeiensis sp. nov., which have 0–5 cones on area V and 4–10 bars on area VI ( Fig. 10C View Fig , Table 3; Glasby and Hsieh 2006: 562, table 2; Villalobos-Guerrero 2019: 489). However, P. kaomeiensis sp. nov. differs from P. mictodonta by having; 1) greater number of paragnaths on area I (9 versus 1–5 (type) or 2–6 (Taiwan); 2) no lateral paragnaths on area III (versus present); 3) even-length bars on area VI (versus uneven-length bars); 4) ɔc-shaped ridge pattern of areas VI – V – VI (versus χ-shaped ridge pattern); 5) notopodial prechaetal lobe present on pre-natatory chaetigers (versus absent in all chaetigers); 6) smaller length ratio of dorsal cirri to dorsal ligule on anterior and posterior chaetigers (about 0.8 and about 0.5 versus 1.07 and 1.04, respectively); 7) no glandular mass in the proximal lobe of dorsal ligule (versus two irregular-shaped glandular masses); 8) only one small lobe at dorsal base of ventral cirri on anterior-half of post-natatory chaetigers (versus auricular lobes continuing to within 10–25 chaetigers before pygidium); and 9) long blade neuropodial heterogomph falcigers (medium-sized blade heterogomph falcigers) ( Fig. 10C, D, G, L View Fig , Table 3; Glasby and Hsieh 2006: 559–562, fig. 5A–F, table 2; Villalobos-Guerrero 2019: 489).

Perinereis kaomeiensis sp. nov. can be distinguished from P. nuntia View in CoL by having; 1) greater number of paragnaths on areas I and III (9 and 54 versus 1–3 (Red Sea) or 0–5 (all) and 9–17 (Red Sea) or 1–30 (all), respectively); 2) no lateral paragnaths on area III (versus present); 3) only bars on area VI (versus bars and cones); 4) ɔc-shaped ridge pattern of areas VI–V–VI (versus χ-shaped ridge pattern); 5) notopodial prechaetal lobe present on pre-natatory chaetigers (versus absent in all chaetigers) and 6) long blade neuropodial heterogomph falcigers (medium-sized blade heterogomph falcigers) ( Fig. 10C, D, L View Fig , Table 3; Glasby and Hsieh 2006: 562–565, fig. 6A–E, table 2; Villalobos-Guerrero 2019: 471, 489). The differences between P. kaomeiensis sp. nov. and eight other new species of group 3A described in the present study are discussed below.

Perinereis kebalanae sp. nov. ( Fig. 11 View Fig , Table 4) urn:lsid:zoobank.org:act:E8412AC0-FAFC-4879-AAF7-A05F4C296129

Material examined: Holotype, NSNM 8748-56 , Daxi (24°56.59'N, 121°54.23'E), habitat type: IRHB, 25 April 2000 GoogleMaps . Paratypes: 1 specimen, NSNM 8748- 57, Shimen (25°17.85'N, 121°34.14'E), habitat type: IRHB, 17 March 2006; 1 specimen, NSNM 8748-58, Jihuei (23°06.87'N, 121°24.21'E), habitat type: IRHB, 27 March 2014.

Etymology: The name is derived from the Kebalan aboriginal tribe, who has settled to northeastern of Taiwan in 13th century.

Description: Based on holotype (atoke, complete) and paratypes (atoke, complete): body length 39.0 (32.5– 52.5) mm with 101 (103–105) chaetigers, chaetiger 10 width 2.0 (2.6–3.0) mm, excluding parapodia; beige in alcohol ( Fig. 11A View Fig ). Prostomium wider than long, lateral antennae antero-lateral, as long as palps, palpophores globose, palpostyles spheroid. Four pairs of tentacular cirri, longest one reaching chaetiger 3. Two pairs of eyes, in trapezoidal arrangement. Tentacular belt about 1.4x (1.2–1.3x) longer than chaetiger 1. Pharynx with dark brown jaws, each with 6 teeth; paragnath pattern: I = 1; II = 19 (19–25) (left), 25 (16–20) (right), in 4 oblique rows; III = 35 (30–35), in 4 transverse rows; IV = 50+4 p-bars near jaw (49–54+3–4 p-bars) (left), 52+4 p-bars near jaw (50+4 p-bars) (right), in 4–6 oblique rows; V = 1; VI = 1 (left), 1 (right), smooth bars; VIIVIII=37 (33–38), in 3 rows. Ridge pattern of areas VI – V – VI, u-shaped ( Fig. 11B View Fig , Table 4).

Dorsal cirri digitiform throughout, medially attached to dorsal ligule, about 1.2–1.3x longer than dorsal ligule on anterior to mid-body chaetigers, subdistally attached to dorsal ligule on posterior chaetigers, about 0.6x as long as dorsal ligule ( Fig. 11C–E View Fig ).

Dorsal ligule conical on anterior chaetigers, about 2.0x longer than median ligule, subconical on mid-body chaetigers, about 2.3x longer than median ligule, becoming rectangular and greatly elongated on posterior chaetigers, about 3.5x longer than median ligule ( Fig. 11C–E View Fig ). Notopodial prechaetal lobe absent.

Median ligule conical, about 1.7x longer than neuroacicular ligule on anterior chaetigers, subconical on mid-body to posterior chaetigers, about 1.5x longer than neuroacicular ligule on mid-body chaetigers, about as long as neuroacicular ligule on posterior chaetigers ( Fig. 11C–E View Fig ).

Neuroacicular ligule with subequal inferior and superior lobes throughout, slightly longer than ventral ligule throughout. Neuropodial postchaetal lobe absent. Ventral ligule subconical throughout. Ventral cirri mid-ventrally attached to ventral edge of parapodia, about as long as ventral ligule throughout ( Fig. 11C–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 present throughout, heterogomph spinigers present on mid-body to posterior chaetigers ( Fig. 11F–H View Fig , Table 4).

Pygidium with anus crenulated; anal cirri cirriform, as long as last 7 (1–3) (n = 3) chaetigers.

Type locality: Daxi, Yilan County, Taiwan.

Distribution: Know from type locality, Shimen (New Taipei City) and Jihuei (Taitung County), Taiwan.

Remarks: Perinereis kebalanae sp. nov. has one bar-shaped paragnath on area VI of the pharynx and greatly expanded notopodial dorsal ligule on posterior chaetigers, which implies it be categorized in group 1B proposed by Hutchings et al. (1991: 271) ( Fig. 11B, E View Fig , Table 4). Six species in this group were reported from East and Southeast Asia, which are: Perinereis amblyodonta (Schmarda, 1861) , P. barbara (Monro, 1926) , P. malayana ( Horst, 1889) , P. nigropunctata ( Horst, 1889) , P. obfuscata ( Grube, 1878) , and P. suluana ( Horst, 1924) ( Wu 1967; Wu et al. 1981 1985; Sun and Yang 2004; Glasby et al. 2016). Of these six species, only P. amblyodonta and P. barbara are similar to P. kebalanae sp. nov., because all have conical and bar-shaped paragnaths on area IV ( Fig. 11B View Fig , Horst 1889: 168; Fauvel 1915: 7; Hutchings et al. 1991: 248; 250, 257–258, 263). However, P. kebalanae sp. nov. can be distinguished from P. amblyodonta by having: 1) one conical paragnath on area I (versus 2–5); 2) only bar-shaped paragnaths on area VI (versus bar-shaped and conical paragnaths); 3) dorsal cirri not greatly exceeding dorsal ligule in length, with about 1.2–1.3x longer than dorsal ligule on anterior chaetigers (versus greatly exceeding dorsal ligule in length); 4) greater length ratio of dorsal cirri to dorsal ligule on posterior chaetigers (about 0.6 versus about 0.3 (based on measurement from the drawing of fig. 3f in Hutchings et al. 1991)); 5) smaller length ratio of dorsal ligule to median ligule on posterior chaetigers (about 3.5 versus about 5.0 (based on measurement from the drawing in fig. 3f in Hutchings et al. 1991)); 6) no notopodial prechaetal lobe (versus present on anterior chaetigers); and 7) neuropodial heterogomph spinigers present on mid-body to posterior chaetigers (versus absent on chaetigers of all body regions) ( Fig. 11B, C, E, H View Fig , Table 4; Hutchings et al. 1991: 247–248, fig. 3a–f).

Perinereis kebalanae sp. nov. is clearly different from P. barbara View in CoL by having: 1) greater number of paragnaths on areas II and III (15–29 and 30–35 versus 6–14 and 3–7, respectively); 2) greater number of cones on area IV (50–54 versus 9–23); 3) fewer number of paragnaths on area V (1 versus 2–7); 4) only bar-shaped paragnaths on area VI (versus bar-shaped and conical paragnaths); 5) fewer number of paragnaths on areas VII–VIII (33–37 versus 45–101); 6) dorsal cirri subdistally attached to dorsal ligule on posterior chaetigers (versus attached 2/3 from the base of dorsal ligule); 7) greater dorsal cirri to dorsal ligule length ratio on anterior, mid-body, and posterior chaetigers (1.3, 1.2 and 0.6 versus 0.6, 0.5, and 0.5, respectively (based on the measurement from fig. 4b, d, e in Hutchings et al. 1991)); 8) dorsal ligule rectangular basally, about 3.5x longer than median ligule on posterior chaetigers (versus very broad basally and curved dorsally, about 2.5x (based on the measurement from fig. 4e in Hutchings et al. 1991) longer than median ligule on posterior chaetigers); 9) no notopodial prechaetal lobe (versus present on anterior to mid-body chaetigers); and 10) neuropodial heterogomph spinigers present on mid-body to posterior chaetigers (versus absent on chaetigers of all body regions) ( Fig. 11B–E, H View Fig , Table 4; Hutchings et al. 1991: 249–250, fig. 4b, d, e). The differences between P. kebalanae sp. nov. and the other new species of group 1B described in the present study are discussed below.

Perinereis liuqiuensis sp. nov. ( Fig. 12 View Fig , Table 3) urn:lsid:zoobank.org:act:B7E103C2-8F32-42DD-BF8F-E2C98DD915FF

Material examined: Holotype, NSNM 8748-59 , Yufu (22°20.90'N, 120°23.38'E), habitat type: ISSB, 11 May 2000. GoogleMaps

Etymology: The name is derived from the name of a small offshore island, Liuqiu, southwestern Taiwan, where the worm was collected.

Description: Holotype, atoke, complete, body length 122.0 mm with 167 chaetigers, chaetiger 10 width 4.2 mm, excluding parapodia; beige in alcohol ( Fig. 12A 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 1.3x longer than chaetiger 5. Pharynx with dark brown jaws, each with 3 teeth; paragnath pattern: I = 3, in longitudinal line; II = 9 (left), 12 (right), in cluster; III = 17 (center region with 13 cones, in 3 transverse rows; 2 lateral regions, each with 2 cones in longitudinal line); IV = 17 (left), 22 (right), in 3 oblique rows, without bars; V = 3, in triangle; VI = 9 (left), 9 (right), even length short bars in transverse row; VII –VIII = 29, in 2 rows. Ridge pattern of areas VI – V – VI, ɔc-shaped ( Fig. 12B View Fig , Table 3).

Dorsal cirri digitiform, medially attached to dorsal ligule throughout, about 0.5x as long as dorsal ligule on anterior to mid-body chaetigers, about 0.3x as long as dorsal ligule on posterior chaetigers ( Fig. 12C–E View Fig , Table 3).

Dorsal ligule subconical throughout, about 1.8–1.9x longer than median ligule throughout; center lobe of dorsal ligule with one oval-shaped glandular mass on posterior chaetigers ( Fig. 12C–E View Fig ). Notopodial prechaetal lobe absent ( Table 3).

Median ligule subconical throughout, slightly longer than neuroacicular ligule on anterior chaetigers, about 1.4–1.5x longer than neuroacicular ligule on mid-body to posterior chaetigers ( Fig. 12C–E View Fig ).

Neuroacicular ligule with predominant inferior lobe on anterior to posterior chaetigers, inferior and superior lobes subequal in length on mid-body to posterior chaetigers, about 0.7–0.8x as long as ventral ligule on anterior to posterior chaetigers. Neuropodial postchaetal lobe absent. Ventral ligule subconical throughout. Ventral cirri mid-ventrally attached to ventral edge of parapodia, about as long as ventral ligule on anterior chaetigers, about 0.7x as long as ventral ligule on mid-body chaetigers, about 0.5x as long as ventral ligule on posterior chaetigers ( Fig. 12C–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 present throughout, heterogomph spinigers present only on mid-body to posterior chaetigers ( Fig. 12F–H View Fig , Table 3).

Pygidium with anus crenulated; anal cirri cirriform, as long as last 11 chaetigers.

Type locality: Yufu intertidal soft bottom, Liuqiu Township, Pingtung County, Taiwan.

Distribution: Known only from type locality.

Remarks: Perinereis liuqiuensis sp. nov. has an arc of nine bar-shaped paragnaths on each side of area VI of the pharynx and not greatly expanded notopodial dorsal ligule, indicating it clearly belongs to group 3A and the Perinereis nuntia species group ( Fig. 12B, E View Fig , Table 3; Hutchings et al. 1991: 271; Wilson and Glasby 1993: 259; Glasby and Hsieh 2006: 558; Villalobos-Guerrero 2019: 468). Of the 20 known species in this species group recognized by Villalobos-Guerrero (2019), only P. shikueii Glasby and Hsieh, 2006 is similar to P. liuqiuensis sp. nov. in terms of having lateral paragnaths on area III, three paragnaths on area V, a range of 4–10 bars (9 in latter species) on area VI, and ɔc-shaped ridge pattern of areas VI – V – VI ( Fig. 12B View Fig , Table 3; Glasby and Hsieh 2006: 562, 567, table 2; Villalobos-Guerrero 2019: 489). However, P. liuqiuensis sp. nov. differ from P. shikueii by having: 1) jaws with fewer teeth (3 versus 6–10); 2) less paragnaths on area II (9–12 versus 17–26); 3) less paragnaths on areas VII –VIII (29 versus 36–52); 4) smaller length ratio of dorsal cirri to dorsal ligule on anterior and posterior chaetigers (about 0.5 and 0.3 versus 0.9–1.08 and 0.69–1.63, respectively); 5) one small, irregular-shaped glandular mass in the center lobe of dorsal ligule on posterior chaetigers (versus one large, round, glandular mass in the center lobe of dorsal ligule); 6) the blade of heterogomph falciger with blunt tip and not tapered off distally (versus point-tipped and significantly tapered off distally); and 7) neuropodial heterogomph spinigers present only on mid-body to posterior chaetigers (versus present on chaetigers of all body regions) ( Fig. 12B–H View Fig , Table 3; Glasby and Hsieh 2006: 562, 567–568, fig. 8A–F, table 2). The differences between P. liuqiuensis sp. nov. and eight other new species of group 3A described in the present study are discussed below.

Perinereis longdongwanensis sp. nov. ( Fig. 13 View Fig , Table 2) urn:lsid:zoobank.org:act:8D2E8D69-51EB-4015-8555-FF1EFD4FEEE6

Material examined: Holotype, NSNM 8748-60 , Longdongwan (25°07.02'N, 121°54.98'E), habitat type: SRHB, 6 November, 2006 GoogleMaps . Paratypes: 3 specimens, NSNM 8748-61–63, collection date, habitat and location information same as holotype. Non-type material: 2 specimens, NSNM 8748-64–65, atoke, collection date, habitat and location information same as holotype.

Etymology: The name is derived from the name of the bay, Longdongwan, where worms were collected.

Description: Based on holotype ( NSNM 8748- 60, atoke, complete) and three paratypes ( NSNM 8748-61–63, atoke, incomplete); holotype for general morphology, oral ring paragnath patterns, parapodial morphology and chaetal morphology; one larger paratype ( NSNM 8748-63) with pharynx dissected for jaw morphology, oral and maxillary ring paragnath patterns, two paratypes ( NSNM 8748-61–62) for oral ring paragnath patterns only: Holotype, atoke, complete, body length 15.5 mm with 46 chaetigers, chaetiger 10 width 0.8 mm, excluding parapodia; paratypes, three specimens incomplete posteriorly, remaining body length 9.0– 15.5 mm with 30–44 chaetigers, chaetiger 10 width 0.7–1.1 mm, excluding parapodia; beige in alcohol ( Fig. 13A–D 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 (3, n = 3). Two pairs of eyes, in trapezoidal arrangement. Tentacular belt about 1.3x (1.3x, n = 3) longer than chaetiger 1. Pharynx with brown jaws, each with 8 teeth; paragnath pattern: I = 5, in transverse row; II = 29 (left), 29 (right), in 3 oblique rows; III = 24, in 5 transverse rows; IV = 33 (left), 31 (right), in 5 oblique rows, without bars; V = 4 (4–16, n = 3), in transverse line; VI = 1 short bar + 2 (2–6, n = 3) small cones (left), 1 short bar + 3 (3–8, n = 3) small cones (right); VIIVIII = 106 (136–194, n = 3) small cones in wide bands. Ridge pattern of areas VI – V – VI, λ-shaped ( Fig. 13E–I View Fig , Table 2).

Dorsal cirri digitiform, attached 1/3 to base of dorsal ligule throughout, about 0.5x as long as dorsal ligule, about 0.7x as long as dorsal ligule ( Fig. 13J, K View Fig , Table 2).

Dorsal ligule subconical throughout, about 1.4x longer than median ligule, about 1.8x longer than median ligule on posterior chaetigers ( Fig. 13J, K View Fig ). Notopodial prechaetal lobe present throughout ( Fig. 13J, K View Fig , Table 2).

Median ligule subconical throughout, about 1.2x longer than neuroacicular ligule on anterior to mid-body chaetigers, about 1.8x longer than neuroacicular ligule on posterior chaetigers ( Fig. 13J, K View Fig ).

Neuroacicular ligule with elongate inferior lobe on anterior to anterior-half of posterior chaetigers, inferior and superior lobes subequal in length on posterior chaetigers, about as long as ventral ligule on anterior chaetigers, about 0.7x 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 0.5x as long as ventral ligule on throughout ( Fig. 13J, K View Fig ).

Notochaetae present from chaetiger 3 to posterior chaetigers, homogomph spinigers present throughout. Supra-acicular fascicle of neuropodia: homogomph spinigers and long-bladed heterogomph falcigers with serrations present throughout. Subacicular fascicle of neuropodia: long-bladed heterogomph falcigers with serrations and homogomph spinigers present throughout ( Fig. 13K–M View Fig , Table 2).

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

Type locality: Longdongwan, New Taipei City, Taiwan.

Distribution: Known only from type locality.

Remarks: Perinereis longdongwanensis sp. nov. has one bar-shaped paragnath on each side of area VI and not greatly expanded notopodial dorsal ligule on posterior chaetigers, it clearly belongs to group 1A proposed by Hutchings et al. (1991: 271) ( Fig. 13H, I View Fig ). Perinereis longdongwanensis sp. nov. can be easily distinguished from the seven species in this group reported from East and South Asia (see the Remarks section in P. houbihuensis sp. nov. for the name of these seven species) by having a unique paragnath pattern of the pharynx: areas I, V, VI, and VII –VIII have 13 cones, 4–16 cones, 1 bar plus 2 to 8 cones on each side, and 140–194 cones, respectively ( Fig. 13E–I View Fig , Table 2; Fauvel 1915: 7; Horst 1924: 174; Hutchings et al. 1991: 250, 253, 255; de León-González and Solís-Weiss 1998: 684; Park and Kim 2017: 256). Of these seven species, only P. dongalae ( Horst, 1924) has 7–8 cones on area I and the other six congeners have only a range of 1–3 cones on the same area ( Ehlers 1868: 504; Grube 1878: 82; Fauvel 1915: 7; Horst 1924: 174; Hutchings et al. 1991: 250, 253, 255; de León-González and Solís-Weiss 1998: 686; Park and Kim, 2017: 256). On the same token, only P. cultrifera ( Grube, 1840) has 2–5 cones on area V and the other six congeners have only a range of 0–3 cones on the same area ( Ehlers 1868: 504; Grube 1878: 82; Fauvel 1915: 7; Horst 1924: 174; Hutchings et al. 1991: 250, 253, 255; de León-González and Solís-Weiss 1998: 686; Park and Kim 2017: 256). None of these seven species has paragnaths on area VII-VIII exceeding 100 cones ( Ehlers 1868: 504; Grube 1878: 82; Fauvel 1915: 7; Horst 1924: 174; Hutchings et al. 1991: 250, 253, 255; de León-González and Solís-Weiss 1998: 686; Park and Kim 2017: 256). Finally, P. tenuisetis ( Fauvel, 1915) is the only species of these seven congeners with long-bladed falcigers as in P. longdongwanensis sp. nov. However, the type of falcigers in the former species is homogomph, whereas that of P. longdongwanensis sp. nov. is heterogomph ( Fig. 13L, M View Fig , Table 2; Fauvel 1915: 8–9, fig. 5e; Horst 1924: pl. 8; Hutchings et al. 1991: 251, 254–255, figs. 5e, 8c, 9c; de León-González and Solís-Weiss 1998: 685, fig. 6E; Park and Kim 2017: 254, fig. 2L). The differences between P. longdongwanensis sp. nov. and four other new species of group 1A described in the present study are discussed below.

Perinereis longdongwanensis sp. nov. has homogomph spinigers in subacicular fascicle of neuropodia on chaetigers of all body regions, which is different from the diagnosis of this genus by Bakken and Wilson (2005: 531) and Glasby (2015: 226) who stated only heterogomph spinigers present in subacicular fascicle of neuropodia. The present study herein emends the generic diagnosis of this part.

Perinereis ludaoensis sp. nov. ( Fig. 14 View Fig , Table 3) urn:lsid:zoobank.org:act:52BC28E6-8206-44CC-897C-28235E42B20C

Material examined: Holotype, NSNM 8748-66 , Baisha (23°38.34'N, 121°29.46'E), habitat type: SRHB, 6 September 1996. GoogleMaps

Etymology: The name is derived from the name of a small offshore island, Ludao, eastern Taiwan, where the worm was collected.

Description: holotype, atoke, without posterior end, remaining body length 138.0 mm with 116 chaetigers, chaetiger 10 width 5.2 mm, excluding parapodia; beige in alcohol ( Fig. 14A 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. 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 = 6, in cluster; II = 11 (left), 11 (right), in 3 oblique rows; III = 17 (center region with 14 cones, in 3–4 rows; 2 lateral regions, each with 1 or 2 cones); IV = 23 (left), 24 (right), in 4 oblique rows, without bars; V = 0; VI = 11 (left), 9 (right), even length short bars in transverse row; VII –VIII = 18, in 2 rows. Ridge pattern of areas VI – V – VI, λ-shaped ( Fig. 14B View Fig , Table 3).

Dorsal cirri digitiform, attached 2/5 to base of dorsal ligule throughout, about 0.5x as long as dorsal ligule on anterior chaetigers, about 0.3x as long as dorsal ligule on mid-body to posterior chaetigers ( Fig. 14C–E View Fig , Table 3).

Dorsal ligule conical on anterior chaetigers, about 3.3x longer than median ligule, subconical on mid-body to posterior chaetigers, about 1.3x longer than median ligule; center lobe of dorsal ligule with one oval-shaped glandular mass on mid-body to posterior chaetigers ( Fig. 14C–E View Fig ). Notopodial prechaetal lobe absent ( Table 3).

Median ligule conical on anterior-most chaetigers, about as long as neuroacicular ligule, subconical thereafter, about 1.7x longer than neuroacicular ligule ( Fig. 14C–E View Fig ).

Neuroacicular ligule truncate distally, with predominant superior lobe on anterior chaetigers, about 0.7x as long as ventral ligule, inferior and superior lobes subequal in length on mid-body to posterior chaetigers, about 0.6x as long as ventral ligule on mid-body to posterior chaetigers. Neuropodial postchaetal lobe absent. Ventral ligule subconical throughout. Ventral cirri mid-ventrally attached to ventral edge of parapodia throughout, about 0.8x as long as ventral ligule on anterior chaetigers, about 0.4x as long as ventral ligule on mid-body to posterior chaetigers ( Fig. 14C–E View Fig ).

Notochaetae present from chaetiger 3 to posterior chaetigers, homogomph spinigers present throughout. Supra-acicular fascicle of neuropodia: homogomph spinigers and medium-sized blade heterogomph falcigers with serrations present throughout. Subacicular fascicle of neuropodia: medium-sized blade heterogomph falcigers with serrations present throughout, heterogomph spinigers present on mid-body to posterior chaetigers ( Fig. 14H, I View Fig , Table 3).

Type locality: Baisha, Ludao Township, Taitung County, Taiwan.

Distribution: Known only from type locality.

Remarks: Perinereis ludaoensis sp. nov. is a species that can be included in group 3A and the Perinereis nuntia species group, which has 9–11 bar-shaped paragnaths on area VI of the pharynx and not greatly expanded notopodial dorsal ligule ( Fig. 14B, E View Fig , Table 3; Hutchings et al. 1991: 271; Wilson and Glasby 1993: 259; Glasby and Hsieh 2006: 558; Villalobos-Guerrero 2019: 468). Of the 20 known species in this group recognized by Villalobos-Guerrero (2019), only P. nuntia (Savigny, 1818) and P. vallata (Grube, 1857) are somewhat similar to P. ludaoensis sp. nov. in terms of number of paragnaths on areas V (both with a range of 0–5 versus 0) and VI (with a range of 4–17 and 5–14, respectively versus 9–11) and the presence of lateral paragnaths on area III ( Glasby and Hsieh 2006: 562, table 2, Villalobos-Guerrero 2019: 489). However, P. ludaoensis sp. nov. can be distinguished from P. nuntia by having: 1) greater number of paragnaths on area I (6 versus ranging 1–5 with an average of 1.8 ± 0.8); 2) only bars on area VI (versus bars and cones); 3) fewer number of paragnaths on areas VII –VIII (18 versus ranging 42–129 with an average of 28 ± 6.2); 4) λ-shaped ridge pattern of areas VI – V – VI (versus χ-shaped ridge pattern); 5) smaller dorsal cirri to dorsal ligule ratio in all body regions (about 0.5 and 0.3 in the anterior body and middle to posterior body regions, respectively versus about 1.0 and 0.5 (based on measurements from drawings of fig. 11B–D in Wilson and Glasby 1993), respectively; 6) an oval-shaped glandular mass in the center lobe of dorsal ligule on mid-body to posterior chaetigers (versus absent); 7) neuroacicular ligule with predominant superior lobe on anterior chaetigers (versus subequal of superior and inferior lobes); and 8) neuropodial heterogomph spinigers present only on mid-body to posterior chaetigers (versus present on chaetigers of all body regions) ( Fig. 14B–E, H, I View Fig , Table 3; Wilson and Glasby 1993: 266–268, fig. 11B– D; Glasby and Hsieh 2006: 562, table 2; Villalobos-Guerrero 2019: 489).

Perinereis ludaoensis sp. nov. differs from P. vallata View in CoL by having: 1) fewer number of paragnaths on areas VII–VIII (18 versus ranging 42–129 with an average of 69.0 ± 13.6); 2) the distal lobe of dorsal ligule about 1.3x longer than median ligule (versus as long as median ligule); 3) absence of notopodial prechaetal lobe on chaetigers of all body regions (versus present on chaetigers 5–25); 4) tip of neuroacicular superior lobe truncate on anterior chaetigers (versus subconical); 5) an oval-shaped glandular mass present in the center lobe of dorsal ligule on mid-body to posterior chaetigers (versus absent); and 6) neuropodial heterogomph spinigers present only on mid-body to posterior chaetigers (versus present on chaetigers of all body regions) ( Fig. 14B–E, H, I View Fig , Table 3; Wilson and Glasby 1993: 269–271, fig. 12D–F; Glasby and Hsieh 2006: 562, table 2; Villalobos-Guerrero 2019: 489). The differences between P. ludaoensis sp. nov. and eight other new species of group 3A described in the present study are discussed below.