Research Article |
Corresponding author: Vivianne Solís-Weiss ( solisw@cmarl.unam.mx ) Academic editor: Christopher Glasby
© 2022 Pablo Hernández-Alcántara, María E. García-Garza, Vivianne Solís-Weiss.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Hernández-Alcántara P, García-Garza ME, Solís-Weiss V (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: 43-58. https://doi.org/10.3897/zookeys.1102.83198
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Notomastus bermejoi sp. nov. from the Gulf of California shelf is described, illustrated, and compared with its congeners bearing hooded hooks in thoracic chaetigers. This new species is characterized by the presence of a prostomial palpode, only notopodia in the first chaetiger, hooded hooks in neuropodia of chaetiger 11, and its distinct 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 11–12. It is mainly distributed in the central Gulf of California in fine sand bottoms (62–96%) at 32–106.4 m depth, tolerating a wide range of temperature (13.2–17.59 °C), dissolved oxygen (0.8–4.93 ml/L), and organic carbon (3.0–7.2%). The type material and original descriptions of Notomastus species with hooks in thoracic chaetigers were examined; an identification key and tables with morphological distinctive characteristics, methyl green staining patterns, and geographic distribution of these close species are provided.
Mexican Pacific, new species, Polychaeta, staining patterns, taxonomy
Capitellids are burrowing worms, usually elongate and thread-like. They are among the most frequently recorded polychaetes in marine soft bottoms, living at a wide bathymetric range from intertidal to deep sea and may even be the dominant organisms in infaunal communities, especially in organically enriched sediments (
The genus Notomastus M. Sars, 1851 is characterized by a thorax with 12 segments: the peristomium and 11 chaetigers; the first thoracic chaetiger is uni- or biramous and the last may have capillary chaetae, hooded hooks, or a mixture of both; in the abdominal chaetigers, hooded hooks are present, while branchiae can be present or absent (
Predictably, in Notomastus, the taxonomic problems detected in other capitellid genera also occur, with several species that do not entirely fit the genus definition, e.g., N. exsertilis Saint-Joseph, 1906 has only 10 thoracic chaetigers and bears capillary chaetae in the first two abdominal segments, or N. hedlandica where capillary chaetae in the first abdominal segment are present (
This confusing situation usually leads to misidentifications. This is the case of Notomastus americanus Day, 1973, which was originally described from off Beaufort, North Carolina, and then reported from the Gulf of California by
The material examined was collected in the continental shelf of the Gulf of California, Mexican Pacific (20°30'–31°38'N, 105°42'–114°50'W), as part of the oceanographic expedition “Cortes 2” (Fig.
Location and environmental conditions of the sampling stations where Notomastus bermejoi sp. nov. was collected.
Station | GPS Coordinates | Depth (m) | Salinity (psu) | Temperature (°C) | Dissolved oxygen (ml/lt) | Organic matter (%) | Sand (%) |
---|---|---|---|---|---|---|---|
39 | 30°59.4'N, 114°04.1'W | 106.4 | 35.16 | 13.2 | 1.73 | 3.0 | 82 |
44 | 30°02.4'N, 112°55.4'W | 104.1 | 35.26 | 14.2 | 2.40 | 7.2 | 74 |
15 | 26°51.1'N, 110°06.5'W | 49.8 | 35.22 | 14.1 | 1.04 | 4.6 | 88 |
50 | 25°46.8'N, 109°35.4'W | 97.0 | 34.99 | 13.2 | 1.47 | 5.7 | 62 |
3 | 25°02.4'N, 108°31.7'W | 32.0 | 35.04 | 14.0 | 1.02 | 5.7 | 96 |
4 | 24°56.9'N, 108°41.8'W | 79.0 | 35.00 | 13.2 | 0.80 | 3.0 | 77 |
49A | 26°59.6'N, 111°50.4'W | 100.0 | 35.10 | 13.2 | 1.34 | 3.6 | 96 |
10 | 25°58.6'N, 111°06.9'W | 39.0 | 35.51 | 17.5 | 4.93 | 4.1 | 87 |
The specimens were examined under dissecting and compound light microscopes, both with an integrated camera for photography. Detailed examination of the chaetal types, distribution, and morphology were supported with scanning electron microscope images: specimens were dehydrated via a graded ethanol series, critical-point dried with liquid CO2, coated with gold, and examined in a JEOL JSM6360LV microscope at the Instituto de Ciencias del Mar y Limnología (
All identified specimens and the type material of the new species were deposited in the Colección Nacional de Anélidos Poliquetos of the
The type material of Notomastus species with hooded hooks in thoracic chaetigers deposited in the National Museum of Natural History, Smithsonian Institution (
Family Capitellidae Grube, 1862
Notomastus latericeus M. Sars, 1851: 199–200.
The genus Notomastus has a conical prostomium, palpode present or absent; eyespots present in multiple spots or absent. Peristomium clearly distinct from prostomium. First chaetiger uniramous or biramous. Eleven thoracic chaetigers. Chaetigers 1–11 with only capillaries or last 1–3 thoracic chaetigers with notopodial capillaries and neuropodial hooks. Abdominal segments with only hooded hooks. Branchiae present or lacking. Genital pores present or absent. Lateral organs present on thorax and abdomen. Pygidium unadorned but unknown for many species (
Notomastus americanus
—
not Notomastus americanus—
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;
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.
Notomastus americanus Day, 1973. Holotype: USA • 1 spec.; North Carolina, Beaufort; 4 Jun. 1965;
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;
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;
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;
The species is named after the Bermejo Sea, as the Gulf of California was originally known, and where this new capitellid was collected.
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.
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.
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).
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.
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 (USNM43118) 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).
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
Comparison of Notomastus species with hooded hooks in thoracic chaetigers.
Species | Length | Palpode | Eyespots | Thoracic epithelium | First chaetiger | Thoracic segments | Neuropodia with hooks | Branchiae |
---|---|---|---|---|---|---|---|---|
N. angelicae Hernández-Alcántara and Solís-Weiss, 1998 | 15 mm (48 segments, incomplete) | Present | Present | 1 to 4 areolated | Biramous | Biannulate | 11 | Not observed |
N. daueri Ewing, 1982 | 65 mm (234 segments, complete) | Absent | Absent | 1 to 4–5 faintly areolated | Biramous | Ventral biannulation | 11 | From chaetiger 60 |
N. mossambicus (Thomassin, 1970) | 32 mm (105 segments, incomplete) | Absent | Present | 1 to 3–4 hexagonal areolation | Uniramous | Uniannulate | 11 | Not observed |
N. precocis Hartman, 1960 | 15.5 (around 50 segments, incomplete) | Present | Absent | Smooth | Biramous | Uniannulate | 9 to 11 | Posterior chaetigers |
N. sunae Lin, García-Garza, Lyu & Wang, 2020 | 33.74 mm (over 100 chaetigers, complete) | Present | Present | 1 to 4–5 slightly areolated | Uniramous | Biannulate | 11 | Not observed |
N. teres Hartman, 1965 | 10.5 mm (35 segments, incomplete) | Absent | Absent | Smooth | Uniramous | Uniannulate | 10 and 11 | Not observed |
Notomastus sp. A of Ewing, 1984a | 4 mm (29 segments, incomplete) | Absent | Present (usually) | Smooth | Uniramous | Uniannulate | 9 (mixed), 10 and 11 | Not observed |
Notomastus bermejoi sp. nov. | 13.5 mm (34 segments, incomplete) | Present | Not observed | 1 to 5–6 tessellated | Uniramous | Biannulate | 11 | Not observed |
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
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 (
Methyl green staining pattern, depth and type locality of Notomastus species bearing hooded hooks in thoracic chaetigers.
Species | Methyl green staining pattern | Depth | Type locality |
---|---|---|---|
N. angelicae Hernández-Alcántara and Solís-Weiss, 1998 | Chaetigers 1–2 medium green, 3–11 dark green | 28.6 m | Sinaloa, Gulf of California |
N. daueri Ewing, 1982 | Chaetigers 3–6 medium green, 7–11 dark green | 5.6–33.5 m | Louisiana, Northern Gulf of Mexico |
N. mossambicus (Thomassin, 1970) | — | 50–70 m | Madagascar |
N. precocis Hartman, 1960 | Chaetigers 1–8 dark green, 9–11 medium green with circle dark green bands | 1305 m | Santa Catalina Basin, California |
N. sunae Lin, García-Garza, Lyu & Wang, 2020 | Thorax blue stained with different intensity; abdomen with a paired stripe of ventral stain, very dark blue colour on dorsum | Intertidal to 23 m | Xiamen Bay, Southern China |
N. teres Hartman, 1965 | Chaetigers 2–10 medium green with dark green bands, 11 dark green | 500–4667 m | Bermuda; New England, USA |
Notomastus sp. A of Ewing, 1984a | — | 19–60 m | Off Texas, Northern Gulf of Mexico |
Notomastus bermejoi sp. nov. | Chaetigers 1–4 slightly stained; chaetigers 5–10 with green bands encircling the segments, chaetigers 11–12 with a darker, solid, green band encircling body | 32–106.4 m | Gulf of California |
In contrast,
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
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
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.
The specimens assigned to this new species were collected on the continental shelf of the Gulf of California and were originally identified as N. americanus due to the key character “presence of neuropodial hooded hooks on the last thoracic chaetiger” (
The examination of the methyl green pattern in the holotype of N. americanus (Fig.
In the family Capitellidae, changes in chaetal structure during ontogeny represent a fundamental taxonomic problem, not only to identify the specimens to the genus level, but also to detect immature individuals. In Notomastus, as in several capitellid genera, during the chaetal development process, the hooks are gradually replaced by capillaries, so that even a mixture of hooks and capillaries can be found in neuropodia of middle and posterior thoracic segments (
The first species described with hooded hooks in thoracic chaetigers was N. precocis by
The occurrence of hooded hooks in thoracic neuropodia had already been discussed by
Therefore, and also in accordance with the observed characters in N. bermejoi sp. nov. and the previous observations provided regarding other species, we can establish that in the genus Notomastus, though variations in the chaetal arrangement are present in several thoracic neuropodia, the presence of exclusively hooded hooks in neuropodia of chaetiger 11 is constant, and it can thus be considered as a stable character to differentiate species.
Although other localities have not yet been well explored, until now, the Notomastus species bearing hooded hooks in thoracic chaetigers have almost entirely been recorded in the American seas. From the eight species described with this morphological characteristic, only N. sunae from southern China and N. mossambicus from Madagascar are reported from other regions. Three species were reported from the Gulf of Mexico or northwestern Atlantic, and in the Eastern Pacific, N. precocis was collected in the deep Santa Catalina Basin, California, while N. angelicae and N. bermejoi sp. nov. were recorded from the continental shelf of the Gulf of California.
1 | First chaetiger biramous | 2 |
– | First chaetiger uniramous | 4 |
2 | Prostomium without anterior palpode; last thoracic neuropodia with a mixture of capillaries and hooks | N. daueri Ewing, 1982 |
– | Prostomium with an anterior palpode | 3 |
3 | Last 2–3 thoracic neuropodia with a mixture of capillaries and hooks; thoracic epithelium smooth | N. precocis Hartman, 1960 |
– | Only last thoracic neuropodia with hooks; epithelium clearly areolated in first 4 thoracic chaetigers | N. angelicae Hernández-Alcántara & Solís-Weiss, 1998 |
4 | Prostomium without an anterior palpode; thoracic chaetigers uniannulated | 5 |
– | Prostomium bearing an anterior palpode; thoracic chaetigers biannulated | 7 |
5 | Thoracic epithelium smooth; with hooks in last 2 or 3 thoracic neuropodia | 6 |
– | Thoracic epithelium areolated in first 3 or 4 chaetigers; with hooks only in neuropodia 11 | N. mossambicus (Thomassin, 1970) |
6 | Neuropodia of chaetigers 10 and 11 with hooded hooks and neuropodia 9 only with capillaries | N. teres Hartman, 1965 |
– | Neuropodia of chaetigers 10 and 11 with hooded hooks and neuropodia 9 with mixed capillaries and hooks | Notomastus sp. A of Ewing, 1984a |
7 | First 4 or 5 chaetigers faintly areolated; body pigmentation: thorax pigmented blue with different intensity, abdomen with a paired stripe of ventral stain | N. sunae Lin, García-Garza, Lyu & Wang, 2020 |
– | First 5 or 6 chaetigers tessellated; body pigmentation: chaetigers 1–4 slightly stained, chaetigers 5–10 with green bands encircling the segments, chaetigers 11 and 12 with a darker, solid, green band encircling body | N. bermejoi sp. nov. |
The Instituto de Ciencias del Mar y Limnología of the Universidad Nacional Autónoma de México provided the financial support to carry out this study. Thanks are due to Michel Hendrickx, head of the institutional project “Cortes”, for inviting us to participate in the oceanographic expeditions. Kristian Fauchald † (National Museum of Natural History, Smithsonian Institution) and Leslie H. Harris (Natural History Museum of Los Angeles County) are thanked for their support during our visits to the collections of the cited Museums. Yolanda Hornelas Orozco is also thanked for her assistance in SEM photography.