European Journal of Taxonomy 220: 1-17

http://dx.doi.org/10.5852/ejt.2016.220

This work is licensed under a Creative Commons Attribution 3.0 License.

ISSN 2118-9773

www. europeanj ournaloftaxonomy. eu

2016 • Parapar J. et al.

Research article

urn:lsid:zoobank.org:pub:87A7BD95-16DC-4219-B0D8-5F46F18F5EF9

A new species of Heterospio (Annelida, Longosomatidae)

from the Indian Ocean

Julio PARAPAR 1 *, Tejal VIJAPURE 2 , Juan MOREIRA 3 & Soniya SUKUMARAN 4

'Departamento de Bioloxia Animal, Bioloxia Vexetal e Ecoloxia, Facultade de Ciencias, Universidade

da Coruna, Rua da Fraga 10, E-15008 A Coruna, Spain.

2 4 CSIR-National Institute of Oceanography (NIO), Regional Centre, Mumbai, India.

3 Departamento de Biologia (Zoologia), Facultad de Ciencias, Universidad Autonoma de Madrid,

Cantoblanco, E-28049 Madrid, Spain.

* Corresponding author: [email protected]

2 Email: [email protected]

3 Email: [email protected]

4 Email: [email protected]

1 urn:lsid:zoobank.org:author:CE188F30-C9B0-44Bl-8098-402D2A2F9BA5

2 urn:lsid:zoobank.org:author:27F44E0B-3479-4F32-90C7-4E58ADlEF0F5

3 um:lsid:zoobank.org:author:BlE38B9B-7751-46E0-BEFD-7C77F7BBBEF0

4 urn:lsid:zoobank.org:author:44610EDC-9965-40FC-AC41-4BB30DB9A85B

Abstract. Knowledge about the taxonomy and distribution of the monogeneric polychaete family

Longosomatidae Hartman, 1944 is limited in all parts of the world. A new species of the genus

Heterospio Ehlers, 1874 (Annelida, Longosomatidae) is described from the Indian Ocean. Heterospio

indica sp. nov. is mainly characterised by the conspicuous flattening of the distal half of capillary chaetae

located in anterior elongated segments. Several body characters of high taxonomic relevance in the

genus are examined under the SEM and discussed. The 18S SSU rDNA and COI genes were sequenced

and represent the first sequencing of a species of Heterospio , and the sequences have been deposited in

Gen Bank.

Keywords. Polychaeta, Heterospio indica new species, taxonomy, SEM, DNA barcodes.

Parapar J., Vijapure T., Moreira J. & Sukumaran S. 2016. Anew species of Heterospio (Annelida, Longosomatidae)

from the Indian Ocean. European Journal of Taxonomy 220: 1-17. http://dx.doi.org/10.5852/eit.2016.22Q

Introduction

The family Longosomatidae Hartman, 1944 comprises a single genus, Heterospio Ehlers, 1874, that

includes eight described species, namely H. longissima Ehlers, 1874, H. longissima Ehlers sensii

Hartman 1965, H. catalinensis Hartman, 1944, H. mediterranea Laubier, Picard & Ramos, 1973,

H. reducta Laubier, Picard & Ramos, 1973, H. peruana Borowski, 1994, H. sinica Wu & Chen, 1996

and H. angolana Bochert & Zettler, 2009 (see Parapar et al. 2014), as well as two described, but still

European Journal of Taxonomy 220 : 1-17 ( 2016 )

Table 1 . Details of sampling locations off the west coast of India where specimens of Heterospio indica

sp. nov. were found.

Area

Study period

Station code

(sampling date)

Location

Depth

(m)

Sediment

Malvan

Premonsoon

M2 (2 Apr. 2013)

16°02 r 41.7" N, 73°26T6.8" E

Clayey silt

Postmonsoon

M4 (29 Jan. 2014)

16°01'37.1"N, 73°25'29.7" E

Clayey silt

Monsoon

M4 (22 Sep. 2014)

Premonsoon

M3 (12 Mar. 2015)

16°02'23.9" N, 73°26'39.4" E

Clayey silt

Ratnagiri

Premonsoon

R1 (7 Apr. 2013)

R3 (8 Apr. 2013)

R4 (8 Apr. 2013)

17°00'27.7" N, 73°16'30.0" E

Silty sand

17°00T4.5" N, 73°15'03.0" E

Sandy silt

17°00'09.1" N, 73°13'50.6" E

Clayey silt

Postmonsoon

R4 (3 Feb. 2014)

17°00'09.1" N, 73°13'50.6" E

Clayey silt

Monsoon

R4 (27 Sep. 2014)

Mumbai

Premonsoon

MY2 (15 Mar. 2013)

18°51T9.0" N, 72°50'37.6" E

Clayey silt

Monsoon

MY4 (24 Sep. 2014)

18°49'36.7" N, 72°47'34.1"E

Sandy silt

Veraval

Premonsoon

V4 (19 Mar. 2013)

20°51'03.4" N, 70°22'36.3" E

Sandy silt

Monsoon

V2 (21 Sep. 2014)

20°53'59.9" N, 70°22'28.8"E

2.5

Sandy silt

unnamed species ( Heterospio sp. A sensu Uebelacker 1984; Heterospio sp. 1 sensu Borowski 1994) and

one undescribed (Knox 1960). Members of this family are mostly reported from muddy sediments on

continental shelfs and slopes worldwide (Wilson 2000). According to Rouse (2001) their elongated body

is characterized by an anterior region composed by 7-9 short segments and provided with 3-8 pairs of

branchial filaments, a post-branchial region composed of elongate segments and a bulbous posterior

region with terminal pygidium. The length of the first elongated segments, number of pairs of branchiae

and chaetal types are the main taxonomic characters used to differentiate between species (e.g., Wu &

Chen 1966; Laubier et al. 1973; Wilson 2000; Bochert & Zettler 2009; Parapar et al. 2014).

The type species of the genus, Heterospio longissima Ehlers, 1874, was described from specimens

collected off the coast of Ireland, NE Atlantic Ocean (Ehlers 1874). This species was subsequently

reported in numerous localities in the same ocean and in the Sea of Japan (see fig. 8 in Parapar et al.

2014). In the Indian Ocean the only records of the genus correspond to one specimen of H. longissima off

the coast of Sudan, Red Sea (Rosenfeldt 1989; Tiirkay 1996; Wehe & Fiege 2002), and two specimens

off the Indian and Pakistani coast of the Arabian Sea (Hartman 1974; Wehe & Fiege 2002; Rao 2005;

Kazmi & Naushaba 2013) (Fig. 1).

During a benthic investigation in shallow waters off the west coast of India, several specimens of

the genus Heterospio were collected; they belong to a new species which is described herein, both

morphologically (including SEM study) and genetically (including 18S SSU rDNA and COI sequences);

information about its habitat is also provided. The distribution of the genus in nearby areas of the Indian

Ocean is also reviewed.

PARAPAR J. et al ., A new species of Heterospio

Table 2. List of PCR and sequencing primers.

Gene Primer

Reference

18S 18SA

584R

COI

HC0 2198

LCO 1490

AYCTGGTTGATCCTGCCAGT

ACGCTATT GGAGCT GGAAT

TAAAC TT C AGGGT GAC C A AAAAAT C A

GGT C AAC AAAT C ATAAAGATATT GG

Medlin et al. (1988)

Persson (pers. comm.); Norlinder et al.

(2012)

Folmer et al. (1994)

Material and methods

This study is based on material collected by several sampling campaigns off the central west coast

of India. Specimens were collected in different seasons across subtidal areas off Malvan, Ratnagiri,

Mumbai and Veraval during 2013-2015 (Table 1). Samples were taken with a van Veen grab with a

0.04 m 2 sampling area. Most of the specimens were fixed in 5% formaldehyde in seawater solution, and

then preserved in 70% ethanol for morphological identification. Some specimens were put directly into

96% ethanol for molecular studies. Samples were sorted at the CSIR-National Institute of Oceanography

(CSIR-NIO), Regional Centre, Mumbai, India. All studied specimens were deposited in the collections

of the Museo Nacional de Ciencias Naturales de Madrid, Spain (MNCN), Senckenberg Research

Institute and Natural History Museum, Frankfurt (SMF) and CSIR-National Institute of Oceanography

(CSIR-NIO), Regional Centre, Mumbai.

Observations, drawings and measurements of specimens were made with an Olympus BX51 compound

microscope equipped with a drawing tube. Specimens were stained with methylene blue for examination

of body and parapodia under the light microscope. For examination with scanning electron microscopy

(SEM), specimens were dehydrated in a graded ethanol series, critical-point dried using C0 0 , mounted on

aluminium stubs, covered with gold in a BAL-TEC SCD 004 evaporator, and examined and photographed

under a JEOL JSM-6400 scanning electron microscope at the Servizos de Apoio a Investigacion (SAI),

University of A Coruna (UDC), Spain.

The description is based on the holotype; features of the posterior end of the body and chaetal fine

structure (SEM micrographs) are from some paratypes. Intraspecific variation is also reported whenever

recorded (e.g., segment size, branchiae arrangement). For the delimitation of body segments we follow

Parapar et al. (2014); these authors propose that chaetae are located on the anterior border of segments

and therefore the length of a segment should be considered as the distance from the chaetal bundle (or

ring) to the chaetal bundle of the next chaetiger. For comparative purposes, one specimen collected by

Rosenfeldt (1989) off the Sudanese coast in the Red Sea was also studied.

Molecular analysis was carried out at CSIR-NIO, Regional Centre, Mumbai. Genomic DNA was

extracted with the DNeasy Blood & Tissue Kit (Qiagen), as per manufacturer protocol. 18S SSU rDNA

was amplified using primers 18SA and 584R resulting in 540-545 bp sequence-lengths. 687 bp of COI

was amplified with HC02198 and LCO1490 primers (for primer references see Table 2). PCR mixtures

for both genes contained 5 pi of Qiagen PCR buffer, 1 pi dNTPs, 38.8 pi ddH^O, 2 pi of each forward

and reverse primer (10 mM), 1 pi template DNA and 0.2 pi Taq polymerase, making a total volume of

50 pi. Amplifications were carried under the following thermal conditions: 94°C for 3.0 min, 30 cycles

of 94°C for 1 min, 48°C (COI) or 50°C (18S) for 1 min and 72°C for 2 mins. A final elongation at 72°C

was carried out for 10 mins followed by cooling the reaction at 4°C. Amplified products were tested on

a 0.8% agarose gel. PCR products were purified with the PCR Purification kit (Qiagen) and sequenced

bidirectionally by the ABi 3730XL Genetic Analyzer: 96 capillary sequencer. The final sequences have

been deposited in Genbank.

European Journal of Taxonomy 220 : 1-17 ( 2016 )

Results

Phylum Ann elida Lamarck, 1809

Family Longosomatidae Hartman, 1944

Genus Heterospio Ehlers, 1874

Type species

Heterospio longissima Ehlers, 1874.

Diagnosis (modified from Borowski 1994)

Body elongated, linear, divided in three regions. Anterior region with 6-8 short chaetigers; median

region with greatly elongated segments; posterior region with few short, inflated segments. Posterior

part of prostomium with a pair of lateral nuchal organs. Proboscis eversible, epithelial pouch. One pair

of grooved peristomial palps, easily lost, leaving scars on lateral surfaces. Anterior region with 3-8 pairs

of cirriform branchiae, usually very long, one pair per segment, arising above notopodia, beginning

from chaetiger 2. Anterior region with biramous parapodia provided with simple capillaries, with or

without acicular spines; elongated segments with chaetae usually forming a cincture near anterior

margin; chaetae simple capillaries, may be accompanied by subuluncini, aristae chaetae, and acicular

spines; posteriormost inflated chaetigers provided with strong acicular hooks.

Remarks

Following Parapar et al. (2014), the terms “thorax” and “abdomen” are not used in the diagnosis due

to the lack of a clear criterion about their limits. The presence of nuchal organs on the prostomium was

included in the diagnosis. The range of 7-9 short anterior chaetigers provided by Borowski (1994) is

modified to 6-8, following Parapar et al. (2014). Peristomial palps were qualified as “easily deciduous”

because they are not reported in most descriptions. More details are provided about the number (range)

and size of branchiae. The term “parapodia biramous” is used here only for anterior segments; it is

also highlighted that in elongated segments there may be a change in the arrangement of chaetae, i.e.,

forming cinctures, although those seem not be present in H. longissima Ehlers, 1874 sensu stricto ,

H. reducta Laubier, Picard & Ramos, 1973 or H. angolana Bochert & Zettler, 2009.

Heterospio indica sp. nov.

um:lsid:zoobank.org:act:8C7B939E-777E-44C6-80F5-1877A49539A4

Figs 1-9; Tables 1-2

Heterospio longissima - Rosenfeldt 1989: 231, fig. 7 (not Ehlers, 1874).

?Heterospio longissima - Hartman 1974: 232 (?not Ehlers, 1874).

Diagnosis

Eight anterior chaetigers short; chaetiger 9 (CH9) first elongated segment. Eight pairs of branchiae in

fully developed individuals. Chaetae forming cinctures from CH10, provided with both thin and robust

capillary chaetae arranged in two rows; both types of chaetae highly flattened in distal half; from CH14

robust capillary chaetae without fine distal end, subuluncini-like, thicker than on previous chaetigers.

Aristate chaetae and acicular hooks not observed on elongated segments.

Etymology

The species is named after the Indian Ocean, where the specimens of the type series were collected.

PARAPAR J. et al., A new species of Heterospio

Type material

Twenty two incomplete specimens and one posterior end were collected in 13 samples along the West

coast of India (Table 1; Fig. 1).

Holotype

INDIA: Malvan, postmonsoon, M4, 29 Jan. 2014, MNCN 16.01/16996.

Paratypes

INDIA: 1 spec., Malvan, premonsoon, M2, MNCN 16.01/16997; 2 spec., Ratnagiri, premonsoon, R3,

NIO/MUM/4/2013/1; 3 spec., Ratnagiri, premonsoon, R4, NIO/MUM/4/2013/2; 1 spec., Mumbai,

premonsoon, MY2, NIO/MUM/3/2013/3; 1 spec., Veraval, premonsoon, V4, NIO/MUM/3/2013/4;

1 posterior end, Malvan, premonsoon, M3, MNCN 16.01/16998; 3 spec., Ratnagiri, premonsoon, Rl,

MNCN 16.01/16999; 3 spec, on SEM stub, Ratnagiri, premonsoon, Rl, MNCN 16.01/16700; 1 spec.,

Ratnagiri, postmonsoon, R4, SMF 24097; 1 spec., Malvan, monsoon, M4, NIO/MUM/9/2014/5; 1 spec.,

Ratnagiri, monsoon, R4, NIO/MUM/9/2014/6; 1 spec., Mumbai, monsoon, MY4, NIO/MUM/9/2014/7;

1 spec., Veraval, monsoon, V2, NIO/MUM/9/2014/8; 1 spec, (sequenced), Ratnagiri, postmonsoon, R4,

NIO/MUM/2/2014/R-H; 1 spec, (sequenced), Malvan, postmonsoon, M4, NIO/MUM/1/2014/M-H.

Type locality

W INDIA: Malvan, 16°0E37.1" N, 73°25'29.7" E, 20 m, clayey silt (Table 1).

Fig. 1 . Distribution of records of Heterospio around the Indian Ocean: Heterospio indica sp. nov.

(present study) (1M), H longissima Ehlers, 1874 (data from Hartman 1974) (5-6) and H. longissima

Ehlers, 1874 (data from Rosenfeldt 1989) (7).

European Journal of Taxonomy 220: 1-17 (2016)

Molecular identification

COI and 18S nucleotide sequences of Heterospio indica sp. nov were submitted to GenBanlc under the

accession numbers: COI-KT259053, KU221229and 18S-KT259051, KT259052.

Comparative material

One specimen collected by Rosenfeldt (1989) off the coast of Sudan, Red Sea (SMF 3795; labelled as

H. longissima).

SG11

CH10

CH12

CH10

SG10

CH13

SG14

CH14

CH10

CH13

CH14

Fig. 2. Heterospio indica sp. nov., holotype (MNCN 16.01/16996). A. General view (scale bar = 2 mm).

B. Anterior end, lateral view (scale bar = 400 pm). C-E. Chaetal arrangement (scale bar = 200 pm),

details. C. CH10. D. CH13. E. CHI4. Abbreviations: bp = branchiophore; bs = branchiostyle; CH =

chaetiger; pa = palp; SG = segment.

PARAPAR J. et al ., A new species of Heterospio

Description of holotype (SEM images from paratypes)

Longest specimen available, incomplete, 39 mm long and 0.95 mm wide, with 14 chaetigers; body

threadlike (Fig. 2A). Prostomium conical, anteriorly rounded (Figs 2B, 4A, 6C, 8C), slightly flattened

dorso-ventrally. Eyes absent. Palp present on right side, reaching level of CH2 (Fig. 2B). Nuchal organs

as deep grooves postero-lateral to prostomium, followed by deep peristomial (SGI) palp scars (Figs 4A,

6C-E). Pharynx sac-like, eversible and unarmed (Fig. 8C).

Anterior body region slightly flattened dorso-ventrally (Fig. 8B). First eight chaetigers (CH1-CH8;

SG2-SG9) short, somewhat more than twice as wide as long. Chaetigers progressively longer from

CH9 (SGIO) onwards. CH9 first elongated chaetiger (FECH), longer than wide, about twice as long

as CH8 (Fig. 2B) (length as distance from chaetal bundle to chaetal cincture of CH10). First chaetiger

(CHI) abranchiate. Eight pairs of filiform branchiae from CH2 to CH9, dorsal to notopodia in almost all

chaetigers and usually composed by short branchiophores and long branchiostyles (Figs 2B, 4B, 6B, F).

From CH10 (SG11) segments strongly elongated and cylindrical in cross section (Figs 6A, 8A); length

increasing in posterior segments; CH10 about five times longer than CH9; CHI 1 (SG12) about 2.5 times

longer than CH10; CH12 (SG13) more than two times longer than CH11; CH13 (SG14) slightly shorter

than CH12; CHI4 incomplete.

Fig. 3. Heterospio indica sp. nov., paratype (MNCN 16.01/16998). A. Posterior end (scale bar = 200

pm). B. Detail of bulbous region of posterior end (scale bar = 100 pm). Abbreviations: ah = acicular

hook; pyg = pygidium; tas = terminal achaetigerous segment.

European Journal of Taxonomy 220: 1-17 (2016)

CH1-CH9 provided with biramous parapodia; noto- and neuropodial chaetal fascicles well separated

(Figs 2B, 5A, D, 7A, 8D, F). Parapodia from CH10 backwards as elongated ridges forming a nearly

closed flange-like cincture near anterior margin of segment (Figs 2A, 5D, 8B). Chaetae of CH1-CH9

simple capillaries, in fan-shaped fascicles (Figs 2B, 4C-D). Neuropodial hooks not observed. Chaetae

of CH10 backwards shorter than those of anterior chaetigers, arranged in two rows (Figs 2C, 5B, 7C);

anterior row of robust capillary chaetae and posterior row of fine capillary chaetae (Fig. 5E-F). Both

types of chaetae circular in cross section at base but quickly flattening outwards and becoming much

thinner at distal end (Figs 5C, F, 7B, D, 8E). Distal ends of both types of chaetae very similar in length

and width, and provided with an opening at the beginning of the terminal flattening (Figs 5C, 7B, 8E).

CH12-CH13 (Fig. 2D) also with some robust capillary chaetae lacking flat distal end (i.e., subuluncini-

like chaetae); CH14 (Fig. 2E) with all robust capillary chaetae of subuluncini-like type. No aristate

chaetae or acicular hooks observed.

For a description of the posterior end, see below.

Fixed specimens creamy white in colour.

Fig. 4. Heterospio indica sp. nov., paratype (MNCN 16.01/17000), SEM micrographs. A. Anterior end,

dorsolateral view (scale bar =100 pm). B. CH2-CH5, dorsal view (scale bar =100 pm). C. CH5-CH9,

dorsal view (scale bar =100 pm). D. CH8-CH10, dorsal view (scale bar =15 pm). Abbreviations: bp =

branchiophore; bs = branchiostyle; CH = chaetiger; nuo = nuchal organ; ps = palp scar; SG = segment.

PARAPAR J. et al., A new species of Heterospio

Fig. 5. Heterospio indica sp. nov., paratype (MNCN 16.01/17000), SEM micrographs. A. SG11-SG12,

dorsal view, framed areas showing chaetal details in (B) and (C) (scale bar = 50 pm). B. Basal part of

CH11 chaetae (scale bar = 5 pm). C. Distal part of CH11 capillary chaetae, arrowheads showing start of

distal opening (scale bar = 5 pm). D. SG12-SG13, dorsal view (scale bar = 100 pm). E. Basal part of

CH12 chaetae (scale bar = 25 pm). F. Distal part of CH12 chaetae (scale bar = 10 pm). Abbreviations:

CH = chaetiger; rcc = robust capillary chaetae; SG = segment; tec = thin capillary chaetae.

European Journal of Taxonomy 220: 1-17 (2016)

Fig. 6. Heterospio indica sp. nov., paratype (MNCN 16.01/17000), SEM micrographs. A. Anterior end,

dorsal view (scale bar = 500 pm). B. Detail of anterior short segments (SG1-SG9) and first elongated

segment (SG10) (scale bar = 250 pm). C. Anterior end, dorsal view, showing nuchal organ and palp

scars, framed area shown in (D) (scale bar = 50 pm). D. Detail of nuchal organ and palp scar, framed

area shown in (E) (scale bar = 20 pm). E. Detail of nuchal organ opening (scale bar = 5 pm). F. Detail of

branchial area, dorsal view (scale bar = 50 pm). Abbreviations: bp = branchiophore; bs = branchiostyle;

CH = chaetiger; nuo = nuchal organ; ps = palp scar; SG = segment.

PARAPAR J. et al ., A new species of Heterospio

Variations

The first body segments show a certain degree of variation for two relevant taxonomic characters:

relative size of first elongated segments and number/size of branchiae. The size of the first elongated

segment (CH9) seems constant, about 2.5-3 longer than any short anterior segment (CH1-CH8); the

relative size of following elongated segments is somewhat variable: CH10 is slightly shorter or longer

than the anterior body region (i.e., from tip of prostomium to posterior end of CH9). This variability

increases for CH11, which is longer than CH10 and may be longer than all preceding segments and

prostomium together (cf. Fig. 6A vs 8A). Variability in sizes might be dependent on the degree of

contraction of the specimen, but it may still be used as a taxonomic character (see Parapar et al. 2014);

however, relative sizes of segments should be reviewed across the genus, because this character has

not been properly assessed in descriptions of other species. On the contrary, variability in number of

branchiae is likely to be size-dependent. Specimens show a wide range of number and sizes of branchiae

that seem to be correlated with the size of individuals (i.e., width at level of anterior non-elongated

segments; see Fig. 9). The presence and number of branchial pairs increases from anterior to posterior

segments; thus, small specimens (<0.4 mm wide) bear four pairs while larger individuals (0.7-0.95 mm)

Fig. 7. Heterospio indica sp. nov., paratype (MNCN 16.01/17000), SEM micrographs. A. Elongated

SG12, CH11 and flange-like neuropod, framed areas showing chaetal details in (B), (C) and (D) (scale

bar = 100 pm). B. Detail of CH11 chaetae, arrowheads showing start of opening end in thin capillary

chaetae (scale bar =10 pm). C. Detail of proximal part of both types of CHI 1 capillary chaetae, anterior

body end at left (scale bar =10 pm). D. Detail of distal part of capillary chaetae (scale bar = 5 pm).

Abbreviations: CH = chaetiger; rcc = robust capillary chaetae; SG = segment; tec = thin capillary chaetae.

European Journal of Taxonomy 220: 1-17 (2016)

Fig. 8. Heterospio indica sp. nov., paratype (MNCN 16.01/17000), SEM micrographs. A. Specimen

showing anterior short segments and first elongated segments, ventro-lateral view (scale bar = 1 mm).

B. Detail of anterior region, ventro-lateral view (scale bar = 300 pm). C. Detail of anterior end, ventral

view (scale bar = 50 pm). D. Flange-like chaetae of CH11, framed area showing chaetal detail in (E)

(scale bar = 100 pm). E. Detail of distal end of both types of capillary chaetae, arrowheads showing start

of opening end in thin capillary chaetae (scale bar =10 pm). F. Flange-like chaetae of CH12 (scale bar =

100 pm). Abbreviations: CH = chaetiger; nuo = nuchal organ; ph = pharynx; ps = palp scar; rcc = robust

capillary chaetae; SG = segment; tec = thin capillary chaetae.

PARAPAR J. et al ., A new species of Heterospio

show up to 7-8 pairs. The presence and size of branchiophores and branchiostyles also shows certain

variability, e.g., in the same specimen there are large and thin branchiostyles indistinctly on large and

small branchiophores.

All specimens are broken at the level of the anterior elongated segments (CHI 2 to CHI 5) but a posterior

region could be examined from a posterior end found in a Malvan sample in March 2015. Only one

posterior region was found, composed of 7 elongated segments and a bulb-like inflated posterior end

provided with 5 chaetigers, a terminal achaetigerous segment and pygidium (Fig. 3A). The last 5

chaetigers are provided with 2-A acicular hooks (Fig. 3B); the anteriormost elongated chaetiger bears

chaetae similar to those of CH10 of the holotype, with flattened distal ends; the chaetae of the other four

elongated chaetigers are similar to those of CH12-14 of the holotype, i.e., of capillary and subuluncini

type.

Specimen from Sudan

The specimen collected by Rosenfeldt (1989) off the coast of Sudan, which was identified as H. longissima

(SMF 3795), has also been examined. It is in poor condition, i.e., incomplete, broken in two pieces,

f-o

% VD O'A

A CHI ^

B£

A. o#

A A

^ CH9 ^

CH10

A CHI ^

a :

. ^ CH9 Au

CH10

^.CHI ^

,A A

CH9

CH10

■O

‘O O'

Malvan

postmonsoon

Holotype

(0.95 mm)

Malvan

premonsoon

(0.80 mm)

Ratnagiri

postmonsoon

(0.70 mm)

■o o

Ratnagiri

premonsoon

(0.35 mm)

A 0 cA cA

Ao cA

CH9

Ao o#

CH10

A, A chi A A CHI A,

■O O'

3 A

CH9

CH10

<S ;

Ratnagiri

premonsoort

(0.40 mm)

CHI

CH9

CH10

Ratnagiri

premonsoon

(0.35 mm)

Ratnagiri

premonsoon

(0.35 mm)

Ratnagiri

premonsoon

(0.25 mm)

• large branchiohore + thick branchiostyle ° only large branchiophore

o large branchiohore + thin branchiostyle

° only short branchiophore

•^Anly

short branchiostyle

Fig. 9. Schematic drawings (not to scale) in dorsal view of some paratypes (MNCN and NIO) of

Heterospio indica sp. nov., showing diversity of branchial arrangement in relation to size. Chaetigers

numbered from CHI (biramous) to CH10 (first flange-like). Width of anterior region indicated.

European Journal of Taxonomy 220: 1-17 (2016)

twisted and flattened dorsoventrally. According to its width (0.6 mm), this specimen fits within the

range of large H. indica sp. nov. and it bears eight pairs of branchiae. Rosenfeldt (1989) highlighted the

presence of palps which are now lacking. However, the relevant features of this specimen agree well

with the description provided above of H. indica sp. nov.

Distribution and ecology

Heterospio indica sp. nov. was found off the west coast of India (Fig. 1) in shallow water (2.5 to 22 m

depth) in mostly clayey silt and sandy silt sediments (Table 1). Hartman (1974) reported H. longissima

based on two specimens from off the NW coast of India and Pakistan. In this article, Hartman (1974)

only mentioned the papers by Ehlers (1895) and Hartman (1965) and did not provide any comparison

with H. mediterranea or H. reducta , the two species described earlier by Laubier et al. (1972-73) from

the Mediterranean Sea. Rosenfeldt (1989) reported H. longissima from Sudan (see above) based on

a single specimen. She illustrated chaetae of the second elongated segment but did not provide any

comparison with other species of Heterospio. Tiirkay (1996), Wehe & Fiege (2002), Rao (2005) and

Kazmi & Naushaba (2013) mentioned these two records without any discussion of the identification

of the reported material. We did not examine the material reported by Hartman (1974) but assume that

it may belong to H. indica sp. nov. because of its geographic proximity to our material. The finding of

the specimen originally reported as H. longissima by Rosenfeldt (1989) and identified here as H. indica

sp. nov. (see above) extends the distribution of the new species to the Red Sea.

Key to world species of Heterospio

The key presented below is based on the provided by Bochert & Zettler (2009) but here the position

and relative length of the first elongated chaetiger (FECH) and the number of pairs of branchiae have

prevalence over chaetal types. The position of FECH in the species follows Parapar et al. (2014).

1 FECH is CH9 .2

- FECH is CH7 or CH8 .7

2. Acicular chaetae in neuropodium of CHI . H. catalinensis Hartman, 1944

- No acicular chaetae in neuropodium of CHI .3

3. Eight pairs of branchiae in adults .4

- Four pairs of branchiae in adults. H. peruana Borowski, 1994

4. FECH of almost same length as all anterior chaetigers together. H. longissima Ehlers, 1874

- FECH clearly shorter than all anterior chaetigers together .5

5. Capillary chaetae of elongated segments (ES) with flattened distal end. H. indica sp. nov.

- Capillary chaetae ofES not flattened.6

6. Aristate chaetae present on elongated chaetigers . H. sinica Wu & Chen, 1996

- Aristate chaetae absent on elongated chaetigers . H. longissima sensu Hartman 1965

7. FECH is CH 8.8

- FECH is CH7 .9

8. Five (or six) pairs of branchiae. Heterospio sp. A sensu Uebelacker 1984

- Seven pairs of branchiae . H. mediterranea Laubier, Picard & Ramos, 1973

9. One pair of branchiae. Heterospio sp. 1 sensu Borowski 1994

- Three pairs of branchiae .10

PARAPAR J. et al ., A new species of Heterospio

10. Length of CH8 about A that of all anterior chaetigers together; very long chaetae in CH8.

. H. reducta Laubier, Picard & Ramos, 1973

- Length of CH8 about A that of all anterior chaetigers together; chaetae in CH8 similar to preceeding

. H. angolana Bochert & Zettler, 2009

Remarks

According to the relative size of anterior segments, Heterospio indica sp. nov. most closely resembles

H. longissima (both the nominal species and H. longissima sensu Hartman 1965), H. catalinensis ,

H. peruana and H. sinica. In these species, the first elongated chaetiger is CH9 while in H. mediterranean

H. reducta , H. angolana , Heterospio sp. A sensu Uebelacker 1984 and Heterospio sp. 1 sensu Borowski

1994, it corresponds to either CH7 or CH8 (see figs 5 and 6 in Parapar et al. 2014). In Heterospio indica

sp. nov., H. longissima sensu Hartman 1965, H. peruana and H. sinica , CH9 is about three times longer

than any anterior segment (CH1-CH8). By contrast, CH9 is about as long as all anterior segments

altogether in H. longissima Ehlers, 1874; H. catalinensis has a CH9 which is slightly longer than CH1-

CH8 and bears acicular chaetae in the neuropodium of CHI. Heterospio peruana only bears four pairs

of branchiae while H. indica sp. nov., H. longissima sensu Hartman 1965 and H. sinica bear eight pairs

instead.

The flattened distal end of the capillary chaetae in the elongated segments in H. indica sp. nov. clearly

distinguishes the new species from H. longissima sensu Hartman 1965 and H. sinica; in the former, both

type of capillary chaetae are greatly different in size and shape while H. sinica bears aristate chaetae

which are not found in the new species.

The COI and 18S SSU rDNA sequences from H. indica sp. nov. are publically available on GenBank

and can be used as a reference for future molecular taxonomic and phylogenetic studies. They are the

first DNA sequences published for any species of Longosomatidae.

Discussion

The main taxonomic characters of the genus Heterospio are the number and length of anterior elongated

segments, the presence or absence of palps and/or nuchal organs, the number of pairs of branchiae, and

chaetal morphology (see Parapar et al. 2014). The study of specimens of H. indica sp. nov., however,

allowed us to amend some comments given by Parapar et al. (2014). For instance, the presence of palps

in Heterospio has been described and/or illustrated in several previous works (e.g., Hartman 1965; Wu &

Chen 1966; Laubier et al. 1973; Borowski 1994); other authors, however, questioned their very presence

(Uebelacker 1984; Bochert & Zettler 2009; Parapar et al. 2014) by interpreting the deep grooves behind

the prostomium as nuchal organs and therefore not as palp scars. Examination of specimens of H. indica

sp. nov. has clearly demonstrated that both palps and nuchal organs are indeed present.

As was previously proposed by Parapar et al. (2014), we consider that the number of short anterior

segments and the relative length of the first elongated segments are two key characters in longosomatid

taxonomy; nevertheless, they should be evaluated carefully because some variation was observed (see

above).

Chaetal terminology in Longosomatidae is surprisingly variable given the small number of described

species. The following terminology has been used for chaetae: aristate, capillary, stout capillary,

subuluncini, transitional subuluncini capillary-like, spines and acicular hooks. A review of this

nomenclature, in the frame of an eventual revision of the genus, seems necessary since some types might

simply be transitional stages of the same type of chaetae, as has already been discussed by Borowski

(1994).

European Journal of Taxonomy 220: 1-17 (2016)

Acknowledgements

The authors are grateful to Ada Castro (SAIN, UDC) for assisting in the preparation of specimens

and use of the SEM, and Dieter Fiege (Senckenberg Research Institute and Natural History Museum,

Frankfurt) who kindly provided the specimen collected by Pongchai Rosenfeldt in the Red Sea. JP and

JM thank the Fauna Iberica Project (Polychaeta VI: Palpata-Canalipalpata I; CGF2014-53332-C5-3-P)

for partial financial support. TV and SS thank MoES (Ministry of Earth Sciences) for providing financial

support through the COMAPS (Coastal Ocean Monitoring and Prediction System) programme and also

the Director of CSIR-National Institute of Oceanography for extending facilities. This is CSIR-NIO

contribution no. 5875. We thank Pat Hutchings (Australian Museum, Sydney) for checking the English

language. Two anonymous referees provided useful comments that greatly contributed to improve this

paper. TV is grateful to CSIR for awarding a Senior Research Fellowship that gave her the opportunity

to carry out the present study.

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Manuscript received: 27 August 2015

Manuscript accepted: 21 March 2016

Published on: 9 August 2016

Topic editor: Rudy Jocque

Desk editor: Kristiaan Hoedemakers

Printed versions of all papers are also deposited in the libraries of the institutes that are members of the

EJT consortium: Museum national d’Histoire naturelle, Paris, France; Botanic Garden Meise, Belgium;

Royal Museum for Central Africa, Tervuren, Belgium; Natural History Museum, London, United

Kingdom; Royal Belgian Institute of Natural Sciences, Brussels, Belgium; Natural History Museum of

Denmark, Copenhagen, Denmark; Naturalis Biodiversity Center, Leiden, the Netherlands.