Notomastus bermejoi, Hernández-Alcántara & García-Garza & Solís-Weiss, 2022

Hernandez-Alcantara, Pablo, Garcia-Garza, Maria E. & Solis-Weiss, Vivianne, 2022, Notomastus bermejoi, a new species of Capitellidae (Annelida, Polychaeta) from the Gulf of California, with morphological remarks on species with hooks in thoracic chaetigers, ZooKeys 1102, pp. 43-58 : 43

Notomastus bermejoi sp. nov.

Figs 2A-J , 3A-F

Notomastus americanus - Hernández-Alcántara and Solís-Weiss 1993: 1034, 1998: 710-711, 1999: 27.

Notomastus americanus not Notomastus americanus - Day 1973: 100, fig. 131n (= N. hemipodus Hartman, 1945 fide García-Garza et al. 2012).

Material examined.

Type locality. Mexico • Gulf of California , Tepoca Cape; 30°02.4'N, 112°55.4'W; 104.1 m. Holotype : from type locality; 17 Mar. 1985; P. Hernández-Alcántara leg.; fine sand sediment; CNAP-POH-17-002. Paratypes: Mexico • 2 specs.; Gulf of California ; same collection data as for holotype; CNAP-POP-005 • 2 specs.; El Fuerte River, Sta. 50; 25°46.8'N, 109°35.4'W; 87 m ; 20 Mar. 1985; same collector as for preceding; fine sand sediment; CNAP-POP-006 • 1 spec.; San Marcial Point, Sta. 10; 25°58.6'N, 111°06.9'W; 39 m; 11 Mar. 1985; same collector as for preceding; fine sand sediment; CNAP-POP-17-007 • 1 spec.: Arboleda Point, Sta. 15; 26°51.1'N, 110°06.5'W; 49.8 m; 12 Mar. 1985; same collector as for preceding; fine sand sediment; coated with gold for SEM studies; CNAP-POP-17-008 • 4 specs.; North Consag Rocks , Sta. 39; 30°59.4'N, 114°04.1'W; 106.4 m ; 16 Mar. 1985; same collector as for preceding; fine sand sediment; LACM-AHF Poly 12858.

Additional material.

Mexico • 1 spec.; Gulf of California, El Fuerte River , Sta. 50; 25°46.8'N, 109°35.4'W; 87 m; 20 Mar. 1985; same collector as for preceding; CNAP-PO-036/GCA-CS-2006 • 1 spec.; San Marcial Point , Sta. 10; 25°58.6'N, 111°06.9'W); 39 m; 11 Mar. 1985; same collector as for preceding; CNAP-PO-036/GCA-CS-2007 • 3 specs.; Arboleda Point, Sta. 15; 26°51.1'N, 110°06.5'W; 49.8 m; 12 Mar. 1985; same collector as for preceding; CNAP-PO-036/GCA-CS-2008 • 1 spec.; Santa Maria Bay , Sta. 3; 25°02.4'N, 108°31.7'W; 32 m; 19 Mar. 1985; same collector as for preceding; CNAP-PO-036/GCA-CS-2009 • 6 specs.; North Consag Rocks , Sta. 39; 30°59.4'N, 114°04.1'W; 196.4 m; 16 Mar. 1985; same collector as for preceding; CNAP-PO-036/GCA-CS-2010 • 2 specs.; Santa Maria Bay, Sta. 4; 24°56.9'N, 108°41.8'W; 79 m; 10 Mar. 1985; same collector as for preceding; CNAP-PO-036/GCA-CS-2011 • 1 spec.; Santa Ines Bay , Sta. 49A; 26°59.6'N, 111°50.4'W; 100 m; 19 Mar. 1985; same collector as for preceding; CNAP-PO-036/GCA-CS-2012 .

Comparative type material examined.

Notomastus americanus Day, 1973. Holotype: USA • 1 spec.; North Carolina, Beaufort; 4 Jun. 1965; USNM 43118. Paratypes: USA • 14 specs.; same collection data as for holotype; USNM 43119.

Notomastus angelicae - Hernández-Alcántara and Solís-Weiss, 1998. Holotype: Mexico • 1 spec.; Gulf of California, El Fuerte River; 25°39.8'N, 109°28.5'W; 28.6 m; 20 Mar. 1985; USNM 180697. Paratypes: Mexico • 5 spec.; same collection data as for holotype; LACM-AHF-POLY-1902 • 5 specs.; same collection data as for holotype; USNM 180698.

Notomastus daueri Ewing, 1982. Holotype: USA • 1 spec.; Louisiana, Northern Gulf of Mexico; 28°56'N, 90°04'W; 27.7 m; 16 Apr. 1980; USNM 71442. Paratype: USA • 1 spec.; same locality as for holotype; 21 Aug. 1980; USNM 71443.

Notomastus precocis Hartman, 1960. Holotype: USA • 1 spec.; Santa Catalina Basin, California, Sta. 2848; 33°18.0'N, 118°42.0'W; 1305 m; 23 Jun. 1954; LACM-AHF POLY 0416.

Notomastus teres Hartman, 1965. Holotype: Bermuda • 1 spec.; Bermuda, Sta. 2; 32°16.5'N, 64°36.3'W; 1700 m; 18 Apr. 1960; LACM AHF 0418. Paratypes: Bermuda • 1 spec.; same collection data as for holotype; LACM AHF 0418 • 1 spec.; same collection data as for holotype; USNM 57105.

Etymology.

The species is named after the Bermejo Sea, as the Gulf of California was originally known, and where this new capitellid was collected.

Diagnosis.

Prostomium conical with anterior palpode. Peristomium and first six chaetigers with tessellated epithelium. Thorax with peristomium and 11 chaetigers; first chaetiger uniramous. Chaetiger 1-10 with only bilimbate capillaries, chaetiger 11 with notopodial bilimbate capillaries and neuropodial hooded hooks. Thoracic and abdominal chaetigers biannulate. Transition between thorax and abdomen marked by chaetal change. Methyl green staining pattern consisting of: chaetigers 1-4 slightly stained, chaetigers 5-10 with green bands encircling the segments, and a darker, solid, green band encircling the body in chaetigers 11 and 12. Abdominal chaetigers with hooded hooks in both rami. Notopodial and neuropodial abdominal hooded hooks of similar shape. Branchiae not observed. Pygidium unknown.

Description.

Holotype incomplete, with 32 segments, 13.5 mm long, 0.8 mm wide. Paratypes incomplete, with 18-40 segments, 6.5-16.5 mm long, 0.7-0.8 mm wide. Colour in ethanol light brown. Prostomium conical, with anterior palpode (Fig. 2A, B ). Proboscis with soft papillae basally, smooth surface distally. Peristomium and chaetigers 1-5 or 1-6 with tessellated epithelium (Fig. 2C ), following thoracic segments smooth (Fig. 2A ). Thorax with 12 segments, including peristomium and 11 biannulate chaetigers with deep intra- and intersegmental grooves (Fig. 2A, C, D ). First chaetiger uniramous with only notopodial capillaries (Fig. 2C ), chaetigers 2-10 with only bilimbate capillaries in both rami, around 8-26 per fascicle; chaetiger 11 with around 25 notopodial bilimbate capillaries; and neuropodia with 5-12 hooded hooks per fascicle (Fig. 2E-G, J ). Hooded hooks with several rows of subapical teeth above main fang, basal row with 3-5 teeth, and apical one multidentate, smooth hood (Fig. 2E ). Notopodia dorsolaterally inserted in first four thoracic chaetigers, then gradually located more dorsally (Fig. 2A ). Neuropodia ventrolateral. Lateral organs present along body, positioned between noto- and neuropodia; thoracic lateral organs oval, close to notopodia (Fig. 2C ); anterior abdominal lateral organs globular, exposed (Fig. 2H ). Genital pores on last thoracic chaetigers, located on intersegmental areas of chaetigers 8/9, 9/10, 10/11, and 11/12 (Fig. 2A ). Transition between thorax and abdomen marked by chaetal change and size of segments (Fig. 2D, G ). Abdominal chaetigers with smooth epithelium and hooded hooks on both rami (Fig. 2F, H ). Abdominal hooks of similar shape to thoracic hooks but shaft shorter (Fig. 2I ). Notopodial lobes close together on anterior abdominal region, chaetal fascicles with 10-16 hooded hooks (Fig. 2H ). Neuropodial lobes lateral, expanded up to dorsal region, ventrally separated (Fig. 2H ); chaetal fascicles with around 20 hooded hooks. Notopodial and neuropodial abdominal hooded hooks of similar shape, shoulder developed and moderate hood (Fig. 2I ); posterior shaft longer than anterior one. Branchiae not observed. Pygidium unknown.

Methyl green staining pattern.

Holotype with prostomium, peristomium, and chaetigers 1-4 slightly stained; chaetigers 5-10 with green bands encircling the biannulate segments, separated by an unstained ring corresponding to the fringe between chaetigers; in chaetigers 11 or 12 a darker, solid, green band encircling body (Fig. 3A ). In paratypes, chaetigers 11 and/or 12 have a darker, solid, green band encircling body (Fig. 3B-E ). In the additional material some thin specimens stained green from chaetiger 2 or 3 and a darker green band only on chaetiger 11 (Fig. 3F ). Abdominal region uniformly stained light green.

Remarks.

So far, seven species of the genus Notomastus bearing hooded hooks on some thoracic parapodia had been accepted as valid species. They can be classified in two main groups: those species with the first chaetiger biramous and those having the first chaetiger uniramous (only notopodium present) (Table 2 ). In the first group we find N. daueri , N. angelicae , and N. precocis Hartman, 1960, from the northern Gulf of Mexico, Gulf of California, and California, respectively. The second group, with species having the first chaetiger uniramous, includes N. teres , Notomastus sp. A of Ewing, 1984a (a species still not formally named), N. mossambicus (Thomassin, 1970), N. sunae Lin, García-Garza, Lyu & Wang, 2020 and the new species N. bermejoi (Table 2 ).

Initially, N. bermejoi sp. nov. can be clearly separated from these species, because in N. teres from Bermuda and New England, Notomastus sp. A from the northern Gulf of Mexico, and N. mossambicus from Madagascar the prostomium lacks an anterior palpode and their thoracic chaetigers are uniannulated. In addition, N. teres has hooded hooks on neuropodia of chaetigers 10 and 11, whereas in Notomastus sp. A, recognized as close to N. teres by Ewing (1984a), the hooded hooks are also present in neuropodia of chaetigers 10 and 11 but also, in neuropodia of chaetiger 9, capillaries and hooks are mixed (Table 2 ). Notomastus mossambicus has only hooded hooks in notopodia of chaetiger 11, but chaetigers 1-10 bear capillary chaetae of two types: one limbate and the other shorter, widely limbate, a character only observed in this species ( Thomassin 1970; Çinar 2005).

Notomastus bermejoi sp. nov. is close to N. sunae from southern China, since both species have an anterior palpode in the prostomium and the neuropodia of chaetiger 11 bear hooded hooks. However, in N. sunae the first 4 or 5 chaetigers are faintly areolated, and mainly display a unique stained pattern: thorax pigmented blue with different intensity and abdomen with a paired stripe of ventral stain, as those observed in N. hemipodus , but with a very dark blue colour on dorsum ( Lin et al. 2020), which is clearly different from that observed in N. bermejoi sp. nov. (Table 3 ).

In contrast, Day (1973) described N. americanus from material collected in Beaufort, North Carolina, which also had a uniramous first chaetiger and hooded hooks in the neuropodia of chaetiger 11. However, earlier, Hartman (1945) had also described N. hemipodus from the same locality with only capillary chaetae in all thoracic chaetigers. The re-examination of the type material of both species, carried out by García-Garza et al. (2012), revealed similarities in their thoracic epithelial texture, a uniramous first chaetiger, an anterior palpode on the prostomium, and mainly the same methyl green staining pattern. Therefore, they reallocated N. americanus as a junior synonym of N. hemipodus .

Thus, the characters of these capitellid species with hooks in thoracic neuropodia are clearly different from those observed in N. bermejoi sp. nov., in which an anterior palpode is present in the prostomium, the thoracic chaetigers are biannulate, a tessellated epithelium is present in the peristomium and in chaetigers 1 to 5-6, all thoracic capillaries are bilimbate, the hooded hooks are present on neuropodia of chaetiger 11 (only one specimen also had hooks in neuropodia 10), and its body pigmentation displayed a pattern not observed in other species: chaetigers 1-4 slightly stained, chaetigers 5-10 with green bands encircling the segments, and chaetigers 11-12 with a darker, solid, green band encircling body (Table 3 ).

Habitat.

At depths of 32-106 m, in bottoms with 62-96% fine sand. Temperature: 13.2-17.5 °C; salinity: 34.99-35.51 psu; dissolved oxygen: 0.80-4.93 ml/L; organic carbon: 3.0-7.2% (Table 1 ).

Distribution.

Notomastus bermejoi sp. nov. was collected in the eastern Gulf of California shelf, from Tepoca Cape to Santa Maria Bay, and in the western Gulf, it was found in Santa Ines Bay and San Marcial Point (Fig. 1 ).

Figures

Figure 1. Gulf of California showing the sampling stations where Notomastus bermejoi sp. nov. was collected.

Figure 2. Notomastus bermejoi sp. nov., paratype (CNAP-POP- 17 - 008) A thoracic region, lateral view B prostomium, frontal view C prostomium and chaetigers 1 - 4, lateral view D chaetigers 8 - 12, lateral view E hooded hook chaetiger 11 F chaetigers 11 - 14, lateral view G neuropodia 10 - 11 H abdominal chaetigers (18 - 21) I abdominal hooded hooks J neuropodia 11, hooded hooks. Abbreviations: Alo = abdominal lateral organs; Gp = genital pores; Pa = palpode; Tlo = thoracic lateral organs. Scale bars: 500 μm (A); 100 μm (B, G); 200 μm (C, D, F, H); 2 μm (E); 5 μm (I); 20 μm (J).

Figure 3. Methyl green staining patterns. Notomastus bermejoi sp. nov. A holotype (CNAP-POH- 17 - 002) B-E paratypes (CNAP-POP- 005 to 008) F additional material (CNAP-PO- 036 / GCA-CS- 2006) G-I Notomastus americanus Day, 1973 (= N. hemipodus Hartman, 1945), holotype (USNM 43118) A thoracic region, lateral view B thoracic and anterior abdominal regions, ventral view C-F thoracic and anterior abdominal regions, lateral view G thoracic and anterior abdominal regions, lateral view H anterior region, lateral view I abdominal region, ventral view. Scale bars: 0.5 mm (A-F); 1 mm (G-I).