Parasphaerosyllis irregulata Gongora-Garza , Tovar-Hernandez & de Leon-Gonzalez, 2024

Gongora-Garza, Gerardo, Tovar-Hernandez, Maria Ana & de Leon-Gonzalez, Jesus Angel, 2024, Re-description of Parasphaerosyllis indica Monro, 1937 (Annelida, Syllidae), with the establishment of a new species from western Mexico, Biodiversity Data Journal 12, pp. 116082-116082 : 116082

Parasphaerosyllis irregulata Gongora-Garza, Tovar-Hernandez & de Leon-Gonzalez sp. nov.

Materials

Type status: Holotype. Occurrence: catalogNumber: UANL 8158 ; occurrenceID: 32578C5D-D36F-5AC7-8996-310037A46514; Taxon: phylum: Annelida; class: Polychaeta; order: Phyllodocida; family: Syllidae; genus: Parasphaerosyllis; specificEpithet: irregulata; Location: higherGeographyID: Tropical Eastern Pacific; continent: America; waterBody: Gulf of California; country: Mexico; countryCode: MX; stateProvince: Baja California Sur; municipality: La Paz; locality: San Lorenzo Channel ; verbatimDepth: 3 m; decimalLatitude: 24.3865; decimalLongitude: -110.315417; Identification: identifiedBy: Gerardo Góngora-Garza, Jesus Angel de Leon-Gonzalez ; Event: eventDate: 2015; year: 2015; month: May; day: 5; fieldNumber: 12; Record Level: institutionID: UANL, NL-INV-002-05-09; collectionID: UANL; institutionCode: UANL; collectionCode: UANL 8158 Type status: Paratype. Occurrence: catalogNumber: UANL 8159 ; individualCount: 1; occurrenceID: CB4EEF8F-DBE8-50DA-9D83-75AFDCF623C2; Taxon: phylum: Annelida; class: Polychaeta; order: Phyllodocida; family: Syllidae; genus: Parasphaerosyllis; specificEpithet: irregulata; Location: higherGeographyID: Tropical Eastern Pacific; continent: America; waterBody: Gulf of California; country: Mexico; countryCode: MX; stateProvince: Baja California Sur; municipality: La Paz; locality: San Lorenzo Channel ; verbatimDepth: 3 m; decimalLatitude: 24.3865; decimalLongitude: -110.315417; Identification : identifiedBy: Gerardo Gongora-Garza , Jesus Angel de Leon-Gonzalez ; Event : eventDate: 05/05/2015; year: 2015; month: May; day: 5; fieldNumber: 12; Record Level: institutionID: UANL, NL-INV-002-05-09; collectionID: UANL; institutionCode: UANL; collectionCode: UANL 8159 Type status: Paratype. Occurrence: catalogNumber: ECOSUR 0000 ; individualCount: 1; occurrenceID: A0689572-82D7-51E0-86FC- 2AD 501C7A7F5; Taxon: phylum: Annelida; class: Polychaeta; order: Phyllodocida; family: Syllidae; genus: Parasphaerosyllis; specificEpithet: irregulata; Location: higherGeographyID: Tropical Eastern Pacific; continent: America; waterBody: Gulf of California; country: Mexico; countryCode: MX; stateProvince: Baja California Sur; municipality: La Paz; locality: San Lorenzo Channel ; verbatimDepth: 3 m; decimalLatitude: 24.386917; decimalLongitude: -110.315111; Identification : identifiedBy: Gerardo Gongora-Garza , Jesus Angel de Leon-Gonzalez ; Event : eventDate: 05/05/2015; year: 2015; month: May; day: 5; fieldNumber: 2; Record Level: institutionID: ECOSUR QNR.IN.021.0497; collectionID: ECOSUR; institutionCode: ECOSUR; collectionCode: ECOSUR 0000 Type status: Paratype. Occurrence: catalogNumber: CNAP-ICML 0000 ; individualCount: 1; occurrenceID: 369F3B1A-7D37-55AB-A9FB-577AB6B82D1C; Taxon: phylum: Annelida; class: Polychaeta; order: Phyllodocida; family: Syllidae; genus: Parasphaerosyllis; specificEpithet: irregulata; Location: higherGeographyID: Tropical Eastern Pacific; continent: America; waterBody: Gulf of California; country: Mexico; countryCode: MX; stateProvince: Baja California Sur; municipality: La Paz; locality: San Lorenzo Channel ; verbatimDepth: 3 m; decimalLatitude: 24.386583; decimalLongitude: -110.315389; Identification : identifiedBy: Gerardo Gongora-Garza , Jesus Angel de Leon-Gonzalez ; Event : eventDate: 05/05/2015; year: 2015; month: May; day: 5; fieldNumber: 9; Record Level: institutionID: CNAP-ICML, UNAM, DFE.IN.061.0598; collectionID: CNAP-ICML; institutionCode: CNAP-ICML; collectionCode: CNAP-ICML 0000 Type status: Paratype. Occurrence: catalogNumber: UANL 8160 ; occurrenceID: 807FE40C-F564-56E4-872E-F55DF8892634; Taxon: phylum: Annelida; class: Polychaeta; order: Phyllodocida; family: Syllidae; genus: Parasphaerosyllis; specificEpithet: irregulata; Location: higherGeographyID: Tropical Eastern Pacific; continent: America; waterBody: Gulf of California; country: Mexico; countryCode: MX; stateProvince: Baja California Sur; municipality: La Paz; locality: San Lorenzo Channel ; verbatimDepth: 3 m; decimalLatitude: 24.386778; decimalLongitude: -110.315056; Identification : identifiedBy: Gerardo Gongora-Garza , Jesus Angel de Leon-Gonzalez ; Event : eventDate: 05/05/2015; year: 2015; month: May; day: 5; fieldNumber: 16; Record Level: institutionID: UANL, NL-INV-002-05-09; collectionID: UANL; institutionCode: UANL; collectionCode: UANL 816

Description

Holotype complete, 35 mm long, 0.9 mm wide, 310 chaetigers. Body pale yellowish, without colour pattern, subcylindrical, ventrally flattened. Prostomium oval, wider than long. Two pairs of eyes in trapezoidal arrangement. Eyes of anterior pair longer than inferior pair, closer to external border of prostomium. Eyespots absent (Fig. 2 A). Three annulate antennae. Median one with 26 articles, located in middle prostomium, between posterior eyes. Lateral antennae inserted in the anterior border of prostomium, with 16 articles each. All antennae longer than prostomium and palps. Palps subtriangular, slightly shorter than prostomium, free at their base (Fig. 2 A). Peristomium as long as first chaetiger (Fig. 2 A, Fig. 4 A-B), with two pairs of tentacular cirri, dorsal ones with 24-25 moniliform articles, ventral ones with 13 articles each (Fig. 2 A, Fig. 4 A-B). Buccal hole with two large lateral edges and a central fissure formed by three irregular pleats. Dorsal cirri long, articulated. Articles near to cirrophore sub-rectangular, wider than long, following ones moniliform; distal article and, on occasions, subdistal ones longer than wide. First pair of dorsal cirri long, with 18 articles each. Cirri from second to sixth parapodia with 16-18 articles. After proventricle end, dorsal cirri alternating one by one (short and long), with 14-18 and 20-22 articles, respectively. In chaetiger 44 appear the first bulbous dorsal cirrus on right side only, with moniliform cirri on left side. From that region to the end of body, articulated cirri with 12-22 articles, with the exception of the last segments where it is growing and has few articles. Nearly spherical dorsal cirri in certain segments (Fig. 4 C and E), while, in others, they are bulbous with distal part lengthened (Fig. 2 B and Fig. 4 D). The presence of spherical/bulbous cirri is irregular, not alternating one by one with moniliform cirri in all segments, but a series of up to 10 bulbous cirri can be present or 3 moniliform cirri in a row, although, sometimes, bulbous and moniliform cirri appear in the same segment forming asymmetric segments (Fig. 5 A-B). Distal end of bulbous cirri with an unarticulated knob, smooth (Fig. 4 C and E), although, in some cases, three or four terminal articles are present on posterior segments (Fig. 2 C and Fig. 4 D). Bulbous cirri with a dorsal band composed of several lines of pores (Fig. 4 C-E, Fig. 5 A-B and E-F), from which numerous groups of filaments or cilia are observed (Fig. 5 E-F). Bulbous cirri present until before the last 20 chaetigers (Fig. 6 B). Subconical parapodial lobe, truncate distally (Fig. 4 D). Ventral cirri conical, distal end rounded, shorter than length of parapodial lobe. Anterior and median chaetigers with two aciculae per parapodia, one of these thicker than the other, both bent lightly in the distal end (Fig. 2 D-E). Posterior parapodia with one acicula, similar in shape to the anterior ones. Anterior parapodia with 9-13 falcigers per fascicle, clearly bidentate with short blades, subequal teeth. Rate of size between dorsal-most versus ventral-most blades: 1.4 (Fig. 3 A, 5D). Median parapodia with 10-13 bidentate falcigers. Blades of falcigers longer than anterior ones, secondary tooth slightly longer than apical one. Size proportion between dorsal-most versus ventral-most blades: 1.2 (Fig. 3 B and Fig. 5 E). Posterior parapodia with around 10 falcigers, similar of those of median parapodia, gradation dorso-ventral 1.5-1.6 (Fig. 3 C). Pre-pygidial parapodia with 6-7 falcigers, larger than those of anterior parapodia, but similar in shape (Fig. 3 D and Fig. 5 F). Dorsal and ventral simple chaetae present on last eight chaetigers (chaetiger 303); dorsal simple chaetae thick and clearly bidentate (Fig. 2 F), the ventral one very thin and slightly bidentate (Fig. 2 G). Pharynx extending through 6 segments, anteriorly surrounded by 10 soft papillae, approximately 1.4 times longer than the length of proventricle, with a thin and acute mid-dorsal tooth inserted anteriorly. Proventricle extending through three segments, with 18 muscle cell rows (Fig. 2 A). Three anal cirri, two lateral articulated with 13 articles and one mid-ventral smooth, very small (Fig. 5 B-C).

Diagnosis

Palps free at their bases. Peristomium as long as first chaetiger. Dorsal cirri from mid-body spherical to bulbous with a long distal end, alternate with long and articulated cirri in an irregular pattern (they are not alternating one by one, both kinds of dorsal cirri may appear on the same segment). Bulbous and spherical dorsal cirri mostly with an unarticulated knob, but those from posterior segments can have two to four distal articles. Bidentate falcigers with short, subtriangular blade, proximal tooth slightly larger than distal one.

Etymology

The specific name refers to the irregular presence of bulbous and moniliform dorsal cirri.

Distribution

Only known from the type locality.

Ecology

The specimens were captured among biofoulers such as coralline algae, bryozoans, hydrozoans and tubes of polychaetes Spirobranchus spp., attached to pyramidal cement structures commonly used to fix coral Pocillopora spp. fragments.

Biology

Schizogamy. Formation of unique dicerous stolon.

Taxon discussion

Parasphaerosyllis irregulata sp. nov., differs from other species in the genus by having palps free at their base ( P. ezoensis , P. indica , P. malimalii and P. uschakovi have palps fused basally) and the presence of an irregular alternation of bulbous and articulated dorsal cirri as follows: spherical to bulbous cirri with 1-3 terminal articulated knobs and moniliform ones, both distributed irregularly, sometimes a spherical/bulbous and moniliform cirrus may appear together within the same segment or only a spherical/bulbous cirrus may appear in several consecutive segments (not alternating one by one as occurs in the other species of the genus). Besides, its is important to emphasise the lost of bilateral symmetry of dorsal cirri in some segments: shape of dorsal cirrus from the right side of a particular segment is not always replicated in the left side as occurs in other species. Furthermore, the size and shape of falciger blades (short and subtriangular) with subequal teeth (proximal tooth slightly larger than the terminal one) is a unique feature (all other four species have falcigers with longer blades than in P. irregulata sp. nov. and proximal tooth being shorter than the terminal one).

The spherical or bulbous dorsal cirri of P. irregulata sp. nov. presumably have glands over its dorsal surface, aligned in several straight rows (Fig. 4 E-F), some empty pores are visible, whereas other pores show short filaments or cilia arising from the holes. Their function is unknown, as well as their presence in P. ezoensis and P. uschakovi , but in the record of San Martín et al. (2008): figs. 19E-F, SEM, as " P. indica " from the Tasman Sea (specimen AM W30153), some pores are visible on the surface of bulbous dorsal cirri, but in the figure, it cannot be seen if the pores are aligned in rows as in P. irregulata or in a scattered pattern. Besides, the specimens from Tasman Sea and Western Australia reported by San Martín et al. (2008): fig. 22A, have bulbous dorsal cirri with dark, fibrillar inclusions forming nearly diagonal lines, as well as those illustrated by Capa et al. (2001): fig. 1D to P. malimalli and those here described in the holotype of P. indica . It is unknown if that pattern is distinctive of these three taxa or not or if these are related to pores or glands.

Figures

Figure 2. Line drawings of Parasphaerosyllis irregulata sp. nov. (holotype UANL 8158). A Anterior end, dorsal view; B Middle section of body, dorsal view; C Posterior bulbous and moniliform dorsal cirri, chaetiger 260; D Acicula, chaetiger 10; E Acicula, posterior chaetiger; F Ventral simple chaeta, chaetiger 302; G Dorsal simple chaeta, chaetiger 302. Scale bars: A, B = 0.5 mm; C = 0.25 mm; D-G = 20 µm.

Figure 3. Line drawings of Parasphaerosyllis irregulata sp. nov. (holotype UANL 8158) A Falcigers from chaetiger 10; B Falcigers from chaetiger 40; C Falcigers from chaetiger 90; D Falcigers from chaetiger 250. Scale bar: A = 20 µm.

Figure 4. Scanning electronic micrographs of Parasphaerosyllis irregulata sp. nov. (paratype UANL 8160). A Anterior end, dorsal view, arrows point to insertion scars of dorsal cirri; B Prostomium and first anterior segments, dorsal view; C Alternated bulbous and moniliform dorsal cirri from mid-body region; D Posterior segments showing different development stages of bulbous dorsal cirri; E Bulbous dorsal cirrus showing dorsal band of several lines of pores; F Detail of ciliate pores on bulbous dorsal cirrus. Scale bars: A, B = 0.5 mm; C, D = 50 µm; F = 5 µm.

Figure 5. Scanning electronic micrographs micrographs of Parasphaerosyllis irregulata sp. nov. (paratype UANL 8160). A Middle section of the body, dorsal view, square showing an enlargement of a spherical cirrus with two terminal articles; B Posterior section of the body, dorsal view, where " b " means bulbous cirrus and " m " moliniform cirrus; C Terminal end, lateral view; D Anterior parapodium with falcigers; E Falcigers from middle body; F Falcigers from posterior parapodia. Scale bars: A, B = 0.5 mm; C = 0.1 mm; D, F = 10 µm, E = 5 µm.

Figure 6. Digital photographs of Parasphaerosyllis malimalii Capa, San Martin and Lopez, 2001 (UANL 8160). A Mid-body segments, showing bulbous and moniliform dorsal cirri; B Falcigers from chaetiger 10; C Falciger and pseudosimple chaeta from middle parapodium; D Pseudosimple chaetae from posterior parapodium. Scale bars: A = 50 µm; B-D = 20 µm.