Echinolaophonte musa, Song & Lee & Kim & George & Khim, 2023
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publication ID |
https://dx.doi.org/10.3897/zse.99.90114 |
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publication LSID |
lsid:zoobank.org:pub:3A394AE0-2903-48B6-9D30-83FC22112B05 |
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persistent identifier |
https://treatment.plazi.org/id/1550C93D-4255-4830-9B5C-6952A27BA0BB |
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taxon LSID |
lsid:zoobank.org:act:1550C93D-4255-4830-9B5C-6952A27BA0BB |
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treatment provided by |
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scientific name |
Echinolaophonte musa |
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sp. nov. |
Echinolaophonte musa sp. nov.
Figs 2 View Figure 2 , 3 View Figure 3 , 4 View Figure 4 , 5 View Figure 5 , 6 View Figure 6 , 7 View Figure 7 , 8 Korean name: Mu-Sa-Chim-Ga-Hok-No-Beol-Re View Figure 8
Locus typicus.
Munseom Islet, Jeju Island, Korea, 33°13'42"N, 126°34'02"E, subtidal sandy bottom (20-30 m in depth) (Fig. 1 View Figure 1 ).
Type material.
Adult female holotype (NIBRIV0000888158) dissected on 12 slides (Rostrum and A1; A2; mandible; maxillule; maxilla; maxilliped; P1; P2; P3; P4; P5; urosome), Munseom Islet, Jeju Island, Korea, coll. H.S. Rho, 01 Oct. 2002. Male allotype (NIBRIV0000888157) dissected on 12 slides (Rostrum; A1; A2; maxilla; maxilliped; P1; P2; P3; P4; P5; cphth; urosome). Paratypes: two females and five males, undissected, ethanol-preserved in vial (NIBRIV0000888156) and two females and four males, as above (MABIKCR00248285-CR00248290).
Additional studied material.
1 female and 1 male, ethanol-preserved, Munseom Islet , Jeju Island, Korea, coll. H.S. Rho, 06 Oct. 2002 ; 1 male, undissected, ethanol-preserved, Sagyeri , Jeju Island, 4 Sep 2008 ; 2 females and 1 male, undissected, ethanol-preserved, Sungsanpo, Jeju Island, 12 May, 2013, coll. S.H. Kim, deposited at the National Marine Biodiversity Institute of Korea (reg. no. MADBK 721114-001) .
Description of the female.
Habitus (Figs 2 View Figure 2 , 3A View Figure 3 ) slender, demarcation between pro- and urosome not clearly discernible, body somites virtually cylindrical. Total body length 660.6 μm (660.6-736.4 μm, mean = 713.1, n = 6), measured from the anterior margin of the rostrum to the posterior margin of the caudal rami. Urosome (Fig. 6A View Figure 6 ) gradually tapering posteriorly. All body somites with paired horn-like spiniform processes bearing long sensilla, except for last two abdominal somites. Paired dorsal processes from first pedigerous somite to first abdominal somite (5 segments, GDS with two pairs of processes) with bifid tip.
Cephalothorax (Figs 2 View Figure 2 , 3A View Figure 3 ) with two small and one long spiniform processes bearing numerous fine, hair-like elements at the mid-line of dorsal surface and a pair of strong and curved lateral processes; with a few scattered spinules and long sensilla. Rostrum very long and stout, with bifurcated tip as shown.
Urosome (Figs 3A View Figure 3 , 6A View Figure 6 ) 5-segmented, comprising P5-bearing somite, genital-double somite, 2 free abdominal somites and telson. Genital double-somite (Fig. 6A View Figure 6 ) slightly wider than long, with long spinules along outer margins. P6 (Fig. 6B View Figure 6 ) represented by 2 long bare setae on a bilobed single plate covering gonopores. Third urosomite widened distally, with long spinules along the outer and distal margins and with 4 long sensilla on the distal corners. Fourth urosomite with fine spinules along the distal margin. Pseudoperculum represented by 3 squarrose lobes (Fig. 3B View Figure 3 ). Caudal ramus (Fig. 3C View Figure 3 ) long and narrow, about 5.3 times as long as greatest width, with a few spinules around setae I and III; with seven bare setae; seta I shortest, setae IV-VI situated distally, seta VII tri-articulate at base, inserted subapically on dorsal surface.
Antennule (Figs 4A, B View Figure 4 ) 6-segmented, all setae bare; segment 1 longest, with long spinular row on inner and outer margins, with 1 seta distally; segment 2 with short inner and long outer spinular row, with 3 short and 4 long bare setae; segment 3 slightly shorter than segment 2, with 5 long setae; segment 4 small, distally with aesthetasc and 2 setae, arising from pedestal; segment 5 shortest, with 1 seta; segment 6 (Fig. 4B View Figure 4 ) with 8 single setae and an acrothek formed by 2 setae and 1 aesthetasc. Setal formula: 1-[1], 2-[7], 3-[5], 4-[2 + ae], 5-[1], 6-[8 + acrothek (2 + ae)].
Antenna (Fig. 4C View Figure 4 ) comprising coxa, allobasis, free endopodal segment and 1-segmented exopod. Coxa small, without ornamentation. Allobasis as long as endopod, with spinular row along inner margin and with 1 small bare abexopodal seta (arrowed in Fig. 4C View Figure 4 ). Exopod long and 1-segmented, bearing spinules on outer margin, with 1 inner and 3 distal setae. Endopod with spinular row along inner margin. Subdistal armature consisting of 1 seta (I in Fig. 4C View Figure 4 ) and 2 spines (II and III in Fig. 4C View Figure 4 ); distal armature consisting of 2 setae (1 and 2 in Fig. 4C View Figure 4 ), 2 spines (3 and 6 in Fig. 4C View Figure 4 ) and 2 geniculate setae (4 and 5 in Fig. 4C View Figure 4 ).
Mandible (Fig. 4D View Figure 4 ). Gnathobase with 4 teeth (1 bi-, 1 tri-cuspidate and 2 with distal spinules) and 1 long unipinnate seta in dorsal corner as depicted; surface without ornamentation. Palp 1-segmented, carrying 1 lateral and 2 distal setae.
Maxillule (Fig. 4E View Figure 4 ). Praecoxa without ornamentation. Arthrite well-developed, with 7 distal spines/setae and 2 anterior surface setae. Coxa with few setules on inner margin, with 1 unipinnate and 1 bare seta distally. Basis with several spinules along inner and outer margin, with 1 unipinnate and 2 bare setae distally. Exopod 1-segmented, elongated, with 2 bare setae distally. Endopod represented by 2 plumose setae.
Maxilla (Fig. 4F View Figure 4 ). Syncoxa with a long spinular row on the outer surface and lots of tiny spinules on the inner proximal surface and with 2 endites, both fused to the syncoxa; proximal endite with 2 bare and 1 multipinnate setae, the latter fused to endite; distal endite with 1 bare, 1 bipinnate and 1 unipinnate seta, the latter fused to endite. Allobasis drawn out into strong claw with 1 accessory seta; Endopod represented by 2 bare setae.
Maxilliped (Fig. 5A View Figure 5 ). Well-developed, prehensile, with elongated syncoxa and basis. Syncoxa with several spinules proximally and subdistally and with 1 short bare and 1 plumose distal seta. Basis elongated, with few spinules on middle outer margin. Endopod represented by an apically curved claw, slightly longer than basis; accessory armature consisting of 1 bare proximal seta.
P1 (Fig. 5B View Figure 5 ). Intercoxal sclerite narrow, bow-like. Praecoxa small, elongated, triangular, with few small spinules on distal corner. Coxa elongated, with long outer and short inner spinules. Basis about 2 times as long as coxa, with a small outer protuberance on the proximal quarter and setule rows on posterior surface, inner and outer margins; with 1 outer seta in proximal third and 1 tiny inner seta subdistally. Exopod 2-segmented, much shorter than enp-1; exp-1 tiny, almost square in shape, with 1 outer seta; exp-2 about 3 times longer than exp-1, with 2 long outer setules, 3 outer and 2 distal bare setae; inner distal seta geniculate. Endopod 2-segmented, prehensile; enp-1 very long, without ornamentation; enp-2 with a tiny seta and a strong claw, the latter about 2 times longer than enp-2.
P2 (Fig. 6C View Figure 6 ). Intercoxal sclerite narrow, unornamented. Praecoxa triangular, unornamented. Coxa almost square, with few spinules on outer surface. Basis smaller than coxa, with few spinules and pore on outer distal surface and with 1 biplumose outer seta. Exopod 3-segmented; exp-1 with spinules on outer margin and 1 short spinular row distally and with 1 bipinnate outer spine; exp-2 shortest, with spinules on outer and distal margin; with 1 bipinnate outer spine and 1 biplumose inner seta; exp-3 with spinules on outer margin, with 3 bipinnate outer spines, 2 distal and 1 inner seta, all biplumose. Endopod 2-segmented, reaching proximal third of exp-3; enp-1 with inner and distal spinules; enp-2 slightly longer than enp-1, with spinules along both margins and with 2 distal and 1 inner seta.
P3 (Fig. 6D View Figure 6 ). Intercoxal sclerite narrow, unornamented. Praecoxa triangular, with spinular row on distal margin. Coxa slightly wider than long, with few spinules on outer surface. Basis nearly as long as coxa, with spinules on outer distal surface and with 1 bare composite outer seta; articulation in the distal third. Exopod 3-segmented; exp-1 with spinules on outer margin and 1 bipinnate outer spine; exp-2 shortest, with outer and distal short spinules, with 1 bipinnate outer spine and 1 biplumose inner seta; exp-3 with spinules on outer margin and with 3 bipinnate outer spines, 2 distal and 2 inner biplumose setae. Endopod 2-segmented, almost reaching margin of exp-2; enp-1 much shorter than enp-2, with spinules along both margins; enp-2 with spinules on both margins, additionally with 2 distal and 2 inner setae.
P4 (Fig. 6E View Figure 6 ). Intercoxal sclerite narrow, unornamented. Praecoxa small and triangular, with few tiny spinules along distal margin. Coxa as long as wide, with outer spinule. Basis with outer spinules and 1 bare composite outer seta. Exopod 3-segmented; exp-1 with spinules on outer and distal margins and with 1 bipinnate outer spine; exp-2 shortest, with outer and distal spinules, with 1 bipinnate outer spine and 1 biplumose inner seta; exp-3 with spinules on outer and distal margins, with 1 bipinnate spine and 1 biplumose seta on outer margin, 2 inner and 2 distal biplumose setae. Endopod 2-segmented, shorter than exp-1; enp-1 short and with few tiny outer spinules; enp-2 with a spinule and 1 tube pore on outer margin, with 2 distal and 1 inner biplumose seta. The armature formula is given in Table 1 View Table 1 .
P5 (Fig. 5C View Figure 5 ) with completely separated baseoendopod and exopod. Baseoendopod reaching middle of exopod, with outer seta arising from elongated setophore bearing 1 tube pore (arrowed) and some spinules at distal half; endopodal lobe reaching half the length of exopod, apically with 1 tube pore (arrowed) and 4 setae. Exopod longer than broad, with spinules on inner and outer margins and distal surface, with 3 plumose setae distally.
Description of male.
Total body length 648.5 μm (642.4-721.2 μm, mean = 681.8 μm, n = 10), measured from anterior margin of rostrum to posterior margin of caudal rami (Fig. 7A View Figure 7 ). Urosome (Fig. 8E View Figure 8 ) gradually tapering posteriorly. Cephalothorax as in female, with numerous fine, hair-like elements and long sensilla on surface as shown in Fig. 7C View Figure 7 ; paired cuticular dorsal processes of first pedigerous somite trifid, those of second pedigerous somite to fourth urosomite with bifid tip. Rostrum very similar to female (Fig. 7A View Figure 7 ).
Urosome (Figs 7C View Figure 7 , 8E View Figure 8 ) 6-segmented, comprising P5-bearing somite, genital somite, third to fifth urosomite and telson. Genital somite and telson without, third to fifth urosomites with long spinules ventrally on distal margin; third and fourth somites with remarkably long sensilla on each distal corner. Pseudoperculum (Fig. 8F View Figure 8 ) represented by 2 pairs of lobes, inner pair with 3 respectively 4 spikes, outer lobes squarrose; the margin in between the lobes bearing fine setules.
Antennule (Fig. 8B View Figure 8 ) 8-segmented; subchirocer, with geniculation between segments 5 and 6; segment 1 longest, with numerous spinules on anterior and posterior surfaces and with 1 small seta on anterior distal corner; segment 2 with long spinules on surface and both margins and with 8 setae, two of which arising from strong pedestal; segment 3 with 3 setae; segment 4 smallest, with 4 setae; segment 5 swollen, with 9 bare setae, 1 bipinnate seta and 1 long seta and aesthetasc arising from long pedestal; segment 6 unarmed; segment 7 with 1 seta; segment 8 with 8 setae and acrothek (2 setae and 1 aesthetasc).
Setal formula: 1-[1], 2-[8], 3-[7], 4-[11 + ae], 5-[0], 6-[1], 7-[8 + acrothek (2 + ae)].
Antenna, mouthparts and P1, P2 and P4 as in female.
P3 (Fig. 8D View Figure 8 ). Both rami very similar to female, except for 2 strong outer pinnate spines (arrowed) on exp-1 and exp-2.
P5 (Fig. 7B View Figure 7 ) with separated baseoendopod and exopod. Baseoendopod with few spinules on anterior surface and distally, 1 tube pore subdistally and 1 outer bare composite seta. Exopod elongate, with 3 biplumose setae distally.
P6 (Fig. 7C View Figure 7 ) very small, bearing a few setules, 1 outer bare composite and 1 plumose inner seta.
Etymology.
The epitheton originates from the Korean word 'mu-sa [ 무사]’, which means “warrior”.
Phylogenetic analysis.
Currently, the taxon Echinolaophonte encloses 16 species: E. armiger , E. brevispinosa , E. briani , E. gladiator , E. horrida , E. hystrix , E. longantennata , E. minuta , E. mirabilis , E. mordoganensis , E. musa sp. nov., E. oshoroensis , E. tetracheir , E. tropica , E. veniliae and E. villabonae . These are in the following referred to as " Echinolaophonte -CS" ("current status") to distinguish them from both Nicholls’ (1941) and the new combination proposed herein (see Discussion). Based on 135 morphological characters (Table 2 View Table 2 ), an exhaustive phylogenetic analysis was undertaken. It included the comparison of 15 Echinolaophonte -CS species; E. longantennata was excluded from the phylogenetic analysis (see below). Furthermore, with Coullia Hamond, 1973 (mostly exemplified by C. tongariki ( Gómez & Boyko, 2006)), Hemilaophonte janinae (Jakubisiak, 1933) and Xanthilaophonte Fiers, 1991, three potential close relatives were selected as outgroups. This is considered here as necessary, because they share features that were seen as characteristic for Echinolaophonte by Nicholls (1941). Moreover, Heterolaophonte minuta (Boeck, 1872) was added as a fourth outgroup to include a comparatively distant representative of Laophontidae .
Eightteen out of 135 characters (= 13.3%) emerged as convergent deviations. They mostly distribute heterogeneously over the species and are set in underlined bold italics in Table 2 View Table 2 . Vertical arrows in characters 31 and 32 (Table 2 View Table 2 ) point towards a further deviation in E. oshoroensis (see Discussion).
The results of the phylogenetic analysis are discussed in detail below. The resulting phylogenetic relationships are presented in Fig. 10 View Figure 10 . The cladogram shows the 135 apomorphies spread over the respective nodes (Figs 10 View Figure 10 , A-EE). For a better orientation, the different nodes, as well as their assigned clades and characters, are summarised in Table 3 View Table 3 , with the hypothesised convergences set in underlined bold italics.
The results suggest that Echinolaophonte -CS consists of several subordinated clades that complicate an unambiguous characterisation of the genus (Fig. 10 View Figure 10 ). Echinolaophonte longantennata had to be excluded from the phylogenetic analysis due to the imprecise and only fragmental description provided by Apostolov (1990), combined with the lack of material for re-examination and comparison. Two synapomorphies were detected for the remaining 15 species, namely a narrowed rostrum (Table 2 View Table 2 , character 13) and the syncoxa of the mxp being almost as long as the basis (Table 2 View Table 2 , character 14). Nonetheless, a further careful comparison resulted in the division of Echinolaophonte -CS: E. tropica was placed into Parechinolaophonte gen. nov. as Pa. tropica (Ummerkutty, 1970), gen. et comb. nov., based on six autapomorphies (Table 2 View Table 2 , characters 15-20; cf. Fig. 10 View Figure 10 , node F) and E. minuta , E. mordoganensis and E. veniliae were transferred into Pseudechinolaophonte gen. nov. as Ps. minuta (Cottarelli & Forniz, 1991), gen. et comb. nov., Ps. mordoganensis (Kuru, Sönmez & Karaytug, 2019), gen. et comb. nov. and Ps. veniliae (Cottarelli, Forniz & Bascherini, 1992), gen. et comb. nov., based on 14 synapomorphies (Table 2 View Table 2 , characters 23-36; cf. Fig. 10 View Figure 10 , node H). The 11 species remaining in Echinolaophonte can be characterised by means of one synapomorphy (Table 2 View Table 2 , character 54, cphth with single spur dorsally on posterior margin; cf. Fig. 10 View Figure 10 , node H). In the following, the generic diagnoses of the two new genera are given.
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