Heteromastus gusipoensis, Jeong, Man-Ki, Soh, Ho Young & Suh, Hae-Lip, 2019
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publication ID |
https://dx.doi.org/10.3897/zookeys.869.34380 |
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publication LSID |
lsid:zoobank.org:pub:50D49A54-A386-4738-AE1F-393B77EC652C |
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persistent identifier |
https://treatment.plazi.org/id/0E904D4E-8DED-483D-A503-C60AFCB1671F |
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taxon LSID |
lsid:zoobank.org:act:0E904D4E-8DED-483D-A503-C60AFCB1671F |
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treatment provided by |
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scientific name |
Heteromastus gusipoensis |
| status |
sp. nov. |
Heteromastus gusipoensis sp. nov. Figures 3 A–G View Figure 3 , 5C, D View Figure 5 , 6B View Figure 6
Material examined.
Holotype: MABIKNA00155561, sex uncertain, Yeonggwang, 35°25.819'N, 126°25.482'E, intertidal, tidal mud-flat, 1 m depth, November 2017, coll. Man-Ki Jeong. Paratypes (2 specimens): MABIK NA00155562 and NA00155563, same information as holotype.
Additional material examined.
MABIK NA00155564, sex uncertain, Yeonggwang, 35°25.819'N, 126°25.482'E, intertidal, tidal mud-flat, 1 m depth, May 2015, coll. Man-Ki Jeong. Additional 16 specimens from type locality on SEM stub.
Diagnosis.
Abdominal hooks with four rows of teeth; three teeth in basal row, three in second row, four in third row, and two in superior row. Genital pores present in intersegmental furrows of between chaetigers 5-6, 6-7, 7-8, 8-9, 9-10, and 10-11. Posteriorly extended parapodial lobes absent on abdominal segments.
Description.
Holotype entire, about 26 mm long, 0.5 mm wide for 120 chaetigers. Paratypes range from 19-24 mm in length, 0.4-0.5 mm width for 75-110 chaetigers. Body thread-like, rounded dorsally, flattened ventrally, widest in anterior thoracic chaetigers, and tapering from abdomen to pygidium. Color yellowish white in alcohol.
Prostomium short, conical, with short and blunt palpode; nuchal organs not seen, eyespots absent ( Fig. 3A, B View Figure 3 ). Everted proboscis with small hemispheric papillae ( Fig. 3B View Figure 3 ). Peristomium weakly bi-annulated and subequal in length with chaetiger 1 ( Fig. 3A, B View Figure 3 ).
Thorax with 11 chaetigers ( Fig. 3A, B View Figure 3 ). Thoracic segments biannulated, with shallow intra- and intersegmental grooves ( Fig. 3A, B View Figure 3 ). First chaetiger biramous, with three or four bi-limbated capillaries; chaetigers 2-5 with six or seven capillaries per fascicle in both parapodia; chaetigers 6-11 with six or seven long-shafted hooded hooks per fascicle ( Fig. 3A, B, F View Figure 3 ); thoracic hooks with indistinct node on shaft and at least 10 small teeth in three rows above the main fang ( Fig. 3F View Figure 3 ). Notopodia located in dorso-laterally, dorsally located in last few thoracic segments; neuropodia located in lateral positions ( Fig. 3A, B View Figure 3 ). Lateral organs present between both parapodia of all thoracic chaetigers, nearer to notopodia in chaetigers three to 11 ( Fig. 3B View Figure 3 ). Genital pores present in intersegmental furrows between chaetigers 5-6, 6-7, 7-8, 8-9, 9-10, and 10-11; sometimes indistinct between chaetigers 5-6 ( Fig. 3B View Figure 3 ).
Transition between thorax and abdomen distinguished by changes in chaetation and shape of segment ( Fig. 3A, B View Figure 3 ); abdominal segments multi-annulated, with short-shafted hooded hooks in posterior part of segment; thoracic chaetigers usually bi-annulated, with long-shafted hooded hooks in center of segment; last thoracic chaetiger usually shorter than first abdominal chaetiger ( Fig. 3A, B View Figure 3 ).
Abdominal parapodial lobes well separated from each other, located in posterior end of each segment ( Fig. 3 A–C View Figure 3 ). Abdominal notopodia separated, mid-dorsal on anterior few segments, becoming dorsolateral in following abdominal region, with five or six hooded hooks per fascicle, not protruded in anterior abdominal region, and very weakly protruded above epidermis in mid-posterior abdomen; not extended over further segment ( Figs 3 A–D View Figure 3 , 5D View Figure 5 ). Abdominal neuropodia separated, not protruded, with six to eight hooded hooks per fascicle; neuropodial lobes less developed than notopodial lobes ( Figs 3 A–C View Figure 3 , 5D View Figure 5 ).
Hooded hooks with main fang extending slightly beyond hoods. Abdominal hooks with distinct node on shaft and four rows of small teeth above main fang; three teeth in basal row, three in second row, four in third row, and two in superior row ( Figs 3E, G View Figure 3 , 5C View Figure 5 ). Pygidium with digitate anal cirrus ( Figs 3D View Figure 3 , 5D View Figure 5 ).
Methyl green staining pattern.
Prostomium, peristomium and thoracic chaetigers 1-2 not stained ( Fig. 6B View Figure 6 ). Thoracic chaetigers 3-10 stained blue; blue speckles restrictively present on the median part of each segment; blue speckles sparse in chaetigers 3-4 ( Fig. 6B View Figure 6 ). Abdominal region without any distinct staining pattern; parapodial lobes of chaetigers 12-13 slightly stained in blue but rapidly fades.
Etymology.
The new species is named for its limited distribution in Gusipo, Korea.
Distribution.
Intertidal area (0-1 m) near Gusipo, Korea.
Ecology.
Heteromastus gusipoensis was sampled in May of 2015 (9 ind./m2) and November of 2017 (71 ind./m2). Most well-developed individuals (having over 120 segments) were obtained in November. Surface sediment of the collecting station was mainly composed of fine sand and silt. Unidentified nereidid polychaetes co-occurred in the same location. The salinity of the sampling location was about 32.
Remarks.
Heteromastus gusipoensis closely resembles H. tohbaiensis Yabe & Mawatari 1998 in the chaetal arrangement and the absence of developed parapodial lobes in posterior abdomen (Table 2). However, they differ in the presence of eyespots on prostomium and distinct node on the shaft of thoracic hooks in H. tohbaiensis (Table 2; Yabe and Mawatari 1998). Moreover, they occur in different habitats and geographical areas. H. gusipoensis only occurs in the marine intertidal zone (salinity ca 32) of southwestern Korea, whereas H. tohbaiensis is only reported from the lacustrine habitat of northern Japan ( Yabe and Mawatari 1998). Heteromastus gusipoensis is readily distinguished from the Korean former record, H. filiformis sensu Choi & Yoon, 2016, by the absence of prostomial eyespots and expanded abdominal parapodial lobes in H. gusipoensis .
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