Echinolaophonte armiger Gurney 1927
Creators: name: Lee, Wonchoel
name: Soh, Ho Young
name: Montagna, Paul A.
Publisher: name: Zenodo
Year: 2006
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Maxillopoda
Harpacticoida
Laophontidae
Echinolaophonte
Echinolaophonte armiger

description: Echinolaophonte armiger (Gurney, 1927)
(Figures 1–6)
Laophonte armiger Gurney, 1927: 554 –556, Fig. 159; Willey, 1930: 108 –109, Figs 65–67; Carvalho, 1952: 159 –160, Pl. II, Figs 68–71.
Onychocamptus armiger: Lang, 1948: 1423 –1424, Abb. 571(12), 580.
Type locality. Port Taufiq, Suez Canal, Egypt.
Material examined
Syntypes: (NHM 1928.4.2.121) 1Ψ dissected on 12 slides, permission to dissect syntype granted by NHM and 2 ΨΨ in 70% alcohol, from Toussoum, Suez Canal, Cambridge Suez Canal Expedition 1924. Other material: 1Ψ dissected on 12 slides (NHM 2003­114), and 1♂ dissected on 11 slides (NHM 2003­115), all from MI686 (37°50’46” N, 31°31’35” W), off Texas coast, Gulf of Mexico, depth 40 m, 22 April 2000, collected by W. Lee.
Description
FEMALE. Total body length 618 µm (measured from anterior margin of rostrum to posterior margin of caudal rami). Largest width measured at about 1/3 from posterior margin of cephalic shield: 182 µm. Urosome gradually tapering posteriorly (Fig. 1 A).
Cephalothorax with smooth posterior margin; lateral posterior side of cephalic shield swollen making triangular expansions at both sides. Pleural areas well developed and rounded without lobate posterolateral angles. Entire surface covered with tiny denticles [expressed as dots] as illustrated in Fig. 1 A–B. Sensillae and few pores present as illustrated in Fig. 1 A–B. Strong, dorsal, spinous process present at median posterior margin; extending to middle of P2 bearing somite (Fig. 1 A). Dorsal median ridge present at cephalothorax. Rostrum rectangular­shaped (Fig. 1 A), with flat anterior margin, completely fused to cephalosome, with pair of sensillae near anterior margin.
Pedigerous somites covered with minute denticles. All prosomites without defined hyaline frills, hind margin smooth. Each pedigerous somite with row of spinules near posterodorsal margin. P3–P5 bearing somites armed with 1 or 2 pair of protuberances within row of spinules near the posterior margin; 1, 2 and 2, respectively. Body slightly constricted between individual somites.
Urosome (Figs 1 A–B, 5A–B) 5­segmented, comprising P5­bearing somite, genital double­somite and 3 free abdominal somites. All urosomites covered with small denticles dorsally and laterally. Genital double­somite and its succeeding somite with 1 pair of spiny processes on posterodorsal margin. Ventral surface of urosomites not markedly wrinkled, ventral hind margin with large spinules laterally and medially. Hyaline frills of urosomites not distinct. Genital double­somite (Figs 1 A–B, 5A–C) with transverse, surface ridge dorsally and laterally, indicating original segmentation; completely fused ventrally. Genital double­somite with additional pair of spiny dorsal processes on its surface, ridge formed originally from 2 anterior urosomites. Genital field located near anterior margin (Fig. 5 A) with very small copulatory pore located in median depression (Fig. 5 C). P6 with small protuberance bearing 2 bare setae, outer seta longer than inner seta; with small blunt process next to inner seta. Pseudoperculum well developed, with pair of digitate processes reaching to middle of anal somite (Fig. 5 B). Anal somite (Fig. 5 B) with smooth, thin operculum flanked by pair of sensillae.
Caudal rami (Fig. 5 A–B) short, cylindrical, 1.4 times longer than wide; each ramus with 7 setae: seta I bare, shortest; setae II and III bare, subequal at length; setae IV and V fused basally, and pinnate (seta V broken off, but presumably longest); seta VI bare and small; seta VII tri­articulate at base. Each ramus with spinules on dorsal surface. Additional spinular ornamentation present along outer margins and around ventral hind margin. Small tube pore present near dorsal anterior margin.
Antennule (Fig. 2 A) 6­segmented, with well developed sclerite around base of segment 1. Segment 1 covered with long spinules. Segment 2 covered with tiny spinules; largest, with small blunt process along the outer margin dorsally. Segment 4 with aesthetasc fused basally to seta and set on distinct pedestal. Armature formula: 1­[1], 2­[7 + 1 pinnate], 3­[6], 4­[1 + (1 + ae)], 5­[1], 6­[9 + trithek]. Apical trithek consisting of small aesthetasc fused basally to 2 bare setae.
Antenna (Fig. 2 B) 3­segmented, comprising of coxa, allobasis, free 1­segmented endopod and 1­segmented exopod. Coxa small, with row of spinules. Allobasis elongate, without distinct surface sutures marking original segmentation, with abexopodal pinnate seta near distal margin. Exopod small, about 3 times longer than wide, with 4 well developed, pinnate setae (2 laterally, 2 apically). Row of spinules along lateral margin posteriorly. Endopod slightly shorter than allobasis, lateral armature arising in distal half, consisting of small, bare seta flanked by 2 strong, pinnate spines. Apical armature consisting of 1 pinnate and 1 bare spine, and 3 geniculate setae (outermost geniculate seta fused basally to short seta). Endopod with 2 rows of long spinules laterally and 2 transverse hyaline frills subapically.
Labrum with spinular ornamentation and covered with tiny spinules as in Fig. 5 D.
Mandible (Fig. 2 D) with well developed gnathobase bearing several multicuspidate teeth around distal margin and pinnate spine at dorsal corner, and with blunt process near distal margin. Palp small, endopod and exopod fused to basis, represented by small peduncles bearing 3 and 1 pinnate setae, respectively. Basal armature represented by pinnate seta.
Paragnaths (not figured) strongly developed lobes with medially directed hair­like setules, separated by medial lobe covered with dense pattern of short setules.
Maxillule (Fig. 2 E). Praecoxa with few spinules around outer margin. Arthrite strongly developed, with naked seta on anterior surface and 9 spines/setae around distal margin. Row of long spinules on posterior surface, and row of small spinules on inner margin of arthrite. Coxa with cylindrical endite bearing naked seta and curved, pinnate spine, with spinule row on anterior surface, and several long spinules around outer margin. Basis with cylindrical endite bearing 2 naked setae and curved, pinnate spine, with several spinules around outer distal margin. Endopod incorporated in basis, forming small peduncle with 2 naked setae. Exopod 1­segmented, with 1 pinnate and 1 naked seta apically and few spinules laterally.
Maxilla (Fig. 2 F). Syncoxa with 2 endites, with row of long spinules along outer margin. Each coxal endite cylindrical with 3 pinnate spines respectively. Allobasis drawn out into strong, slightly curved, distally pinnate claw; accessory armature consisting of naked seta on anterior surface. Endopod represented by 2 naked setae.
Maxilliped (Fig. 2 C) with 2 plumose setae and several patches of spinules on syncoxa. Basis with 2 rows of spinules along outer margin and tiny spinules along palmar margin and surface. Endopod drawn out into long, naked claw, with short, naked seta at base.
Swimming legs P1–P4 (Figs 3 A–B, 4A–B) with wide intercoxal sclerites and well developed praecoxae bearing row of spinules along distal margin. Coxae and bases with anterior rows of surface spinules as figured. Exopods 3­segmented, endopods 2­segmented except in P1. P1 exopod 2­segmented.
P1 (Fig. 3 A). Coxa large, with several spinular rows and patches as figured. Anterior tube pore present near articulation with basis. Basis with strong, bipinnate spine on distal pedestal, long setules along inner margin and stout, bipinnate spine and spinules along outer margin. Anterior surface covered with spinules. Exopod small. Exp­1 with unipinnate spine. Exp­2 with 3 unipinnate spines and 2 geniculate setae. Enp­1 4 times as long as exopod, with short spinules along distal outer margin. Enp­2 with strong, denticulate claw and small, naked seta at base.
P2–P4 (Figs 3 B, 4A–B). Coxae and bases with spinular rows along outer margin and anterior surface. Basis with tube pore on anterior surface. Outer margin of basis with bipinnate spine (P2) or naked seta (P3–P4); arising from setophore in P3–P4. All segments with pattern of spinules as figured. Inner margins of exopod and endopod segments with long setules or spinules. Tube pore present near distal margin of enp­ 1 in P2 and enp­ 2 in P3–P4. P2 enp­2 1.25 times longer than enp­1, endopod reaching to middle of exp­3, and exp­1 longest. P3 enp­2 2.5 times longer than enp­1, endopod reaching to proximal third of exp­3, and exp­3 longer than exp­1. P4 enp­2 2.2 times longer than enp­1, endopod reaching to proximal margin of exp­2, and exp­3 longer than exp­1. Spine and setal formulae as follows:
P5 (Fig. 3 C) exopod and baseoendopod separate; each covered with spinules as figured. Baseoendopod forming short, outer setophore bearing basal seta and tube pore near proximal area of setophore. Endopodal lobe not reaching to distal margin of exopod, with 1 apical and 3 lateral, pinnate setae; tube pore near base of exopod. Exopod elongate, about 2 times longer than wide, with 3 pinnate setae, each seta arising from distinct cylindrical process.
MALE. Body length 565 µm. Largest width measured at about 1/3 from posterior margin of cephalic shield: 168 µm. Urosome distinctly narrower than prosome (Fig. 6 A).
Prosome (Fig. 6 A) 4­segmented, comprising cephalothorax and 3 free pedigerous somites. Entire surface covered with tiny denticles as in Ψ. Strong dorsal median spinous process present near posterior margin, extended to middle of P 2 bearing somite (Fig. 6 A). Rostrum rectangular­shaped (Fig. 6 A), with flat anterior margin, completely fused to cephalosome, and with pair of sensillae near anterior margin. Urosome (Fig. 6 A) 6­ segmented, comprising P5­bearing somite, genital somite and 4 abdominal somites.
Antennule (Fig. 6 B–G) 8­segmented and subchirocer with geniculation between segments 5 and 6. Segment 1 covered with several rows of long spinules. Segment 2 without small knob on dorsal surface. Segment 4 represented by small sclerite along anterior margin (inserted in Fig. 6 C). Segment 5 swollen. Segment 6 with 3­dimensional process as in Fig. 6 E–F. Segment 8 with triangular distal half. Segmental homologies: 1­I, 2­(II­VIII), 3­(IX­XII), 4­XIII, 5­(XIV­XX), 6­(XXI­XXII), 7­XXIII, 8­(XXIV­XXVIII). Armature formula: 1­[1], 2­[9], 3­[8], 4­[2], 5­[8+1 pinnate+2 modified+(1 + ae)], 6­[5 spinous processes], 7­[1], 8­[8+trithek]. Apical trithek consisting of minute aesthetasc and 2 naked setae.
P2–P4 (Fig. 5 E–F). Intercoxal sclerites and protopods as in Ψ, with surface ornamentation as figured. Exopodal segments slightly bent toward endopod. Endopods without sexual dimorphism. P2 without distinct sexual dimorphism. P3 exopod (Fig. 5 E) slightly bent inwards, exp­1 as long as exp­3, outer and distal spines of exopod slightly thicker than in Ψ. P4 exopod (Fig. 5 F) slightly bent inwards, exp­1 longer than exp­3, outer spines of exp­2 and ­3 and distal spine of exp­3 thicker than in Ψ.
P5 (Fig. 5 G) fused medially, defined at base. Baseoendopod with short, small setophore bearing outer basal seta, and obsolete endopodal lobe represented by tube pore along medial margin, with another tube pore near articulation with setophore. Several rows of coarse spinules along outer margin, and near articulation with exopod. Exopod slightly longer than maximum width, with 3 pinnate setae and several large spinules on anterior surface.
P6 (Fig. 5 G) asymmetrical, represented on both sides by small plate: fused to ventral wall of supporting somite along right side, articulating at base and covering gonopore along left side. Outer distal corner produced into cylindrical process bearing few spinules, 1 bipinnate inner and 1 naked outer seta. Outer seta arising from setophore.
description: Published as part of Lee, Wonchoel, Soh, Ho Young & Montagna, Paul A., 2006, Redescription of Echinolaophonte armiger (Gurney) (Copepoda: Harpacticoida) from the Gulf of Mexico, pp. 53-68 in Zootaxa 1250 on pages 55-64, DOI: 10.5281/zenodo.173003