Lysianopsis adelae, Winfield, Ignacio & Ortiz, Manuel, 2009

Winfield, Ignacio & Ortiz, Manuel, 2009, Lysianopsis adelae, new species of amphipod (Gammaridea: Lysianassidae) from the Veracruz Coral Reef System, SW Gulf of Mexico, Zootaxa 2205, pp. 53-61 : 54-61

Lysianopsis adelae n. sp.

( Figs. 1–4 )

Material examined. Holotype: male 7.9 mm ( CNCR # 25299); Veracruz Coral Reef System, Veracruz State, Mexico, SW Gulf of Mexico; 22 May 2007; Isla Verde Coral Reef, 19°12’00.0’’ N, 96°04’04.4’’W; collected in the sediment at the base of the sponge Aplysina fistularis ( Verongida : Aplysinidae ) ( CNPGG # 0878); 10 m depth.

Diagnosis. Eyes big, subrectangular. Cephalic lobes long, pronounced. Rostrum reduced. Epistome narrow, not produced forward, slightly concave; upper lip subquadrate, projecting slightly beyond epistome. Mandibular palp article 3 with 20–25 short marginal F3 setae. Outer plate of maxilla 1 with 11 terminal setalteeth in a 7/4 arrangement, each with 3–7 cusps (left), 3–9 cusps (right). Gnathopod 1 of male slightly prehensile. Dactylus of gnathopod 2 lanceolate, longer than corner of palm. Basis of pereopod 7 with short setae, slightly convex at posterior margin. Uropod 3 with short peduncle, subequal to length of outer ramus, length 1.4 x width, outer ramus 2-articulate, article 2 poorly defined. Telson with truncate distal margin, 2 plumose setae on corners of distal margin, 2 submedian plumose setae dorsally.

Etymology. The new species is named after Dra. Adela Monreal Gómez, researcher (Physical Oceanography) at the Instituto de Ciencias del Mar y Limnología, Universidad Nacional Autónoma de México.

Description. Holotype male, 7.9 mm. Head and body without setae ( Fig. 1 ).

Head ( Figs. 1 A, 4A): slightly longer than deep, cephalic lobes long, pronounced, distally rounded; ventral margin with a small notch; rostrum reduced; eyes subrectangular, compound, vertically elongate.

Antenna 1 ( Figs. 1 A, 4A): short, slightly longer than antenna 2; article 1 of peduncle short, length 1.2x width, 3–4 brush setae on dorsal – ventral margins; articles 2+3 shorter than article 1, setae on distal margin; article 2, 1–2 distal brush setae on ventral margin; accessory flagellum long, 0.5x primary flagellum, 6– articulate, articles with short setae on distal margins; primary flagellum 13–articulate, callynophore absent, short aesthetascs on distal margin of articles 2–3, short setae on distal margins of articles.

Antenna 2 ( Figs. 1 A, 4A): slightly shorter than antenna 1, 1–2 brush setae on peduncular articles, slightly geniculate between peduncular articles 3–4, long setae on distal margin of peduncular articles 3–4, flagellum 10–articulate, articles with short setae on distal margins, without calceoli.

Mounthpart bundle: subquadrate. Epistome - upper lip separate ( Fig. 2 A); epistome narrow, not produced forward, slightly concave; upper lip projecting slightly beyond epistome, subquadrate. Mandible ( Fig. 2 B): incisors symmetrical, large, strongly concave margins; lacinia mobilis a long slender peg; accessory setal row, left row with 4, right row with 5 short, narrow, subequal marginal setae; intermediate setae absent; protuberance on medioposterior margin; molar subequal in width to thickness of mandible, setose, distal margin with vestigial triturative surface; mandibular palp attached proximally, article 1 shorter than article 2 (0.5x), length 2.2x width; article 2 long, length 3.5x width, row of 6 distal plumose A2 setae, 5 long D2 setae in distal third of posterior margin; article 3 lanceolate, length 0.7x article 2, (right) 4 medial D3 setae, 4 distal D3 setae, 1 apical E3 seta, 20–25 short marginal F3 setae, (left) 3 medial D3 setae, 5 distal D3 setae, 2 apical E3 setae, 15 short marginal F3 setae. Maxilla 1 ( Fig. 2 C): inner plate narrow, elongate, with 2 subequal, apical pappose setae, several small, thin setae on proximal margins - distal region; outer plate with 11 setal–teeth in a 7/4 arrangement; (left) ST1 short, thin, 3–cuspidate; ST2 long, thin, 3–cuspidate; ST3 long, thin, 5– cuspidate; ST4 long, thin, 4–cuspidate; ST5 long, robust, 4–cuspidate; ST6 long, thin, 7–cuspidate, ST7 long, thin, 7–cuspidate; (right) 7/4 arrangement with ST7 slightly asymmetrical to left ST7, 9–cuspidate, slightly thinner than left. STA long, thin, 3–cuspidate; STB long, thin, 3–cuspidate; STC short, thin, 4–cuspidate; STD short, thin, 3–cuspidate; posterior margin with 13 minute setae distally, 50–55 short, thin setae on apical margin; palp longer than outer plate, 2–articulate, weakly serrate apical margin, a short - robust seta on distolateral corner, 2 short - robust setae, 1 minute seta on distomedial margin. Maxilla 2 ( Fig. 2 D): inner – outer plates narrow; inner slightly shorter – thicker than outer, 9 long - thin setae, 10 short setae, both on distomedial margin; outer plate with apical crest of 18–20 distally long - thin setae. Maxilliped ( Fig. 2 E): inner plate long, subrectangular, with 3 apical nodular setae, oblique setal row strong, with 9 pappose setae + 9 thin setae, 2 distal – 2 proximal short setae on lateral margin; outer plate broad, longer than inner plate, subrectangular, distal margin slightly crenulate with vestigial submarginal setae, a proximal protuberance on lateral margin; palp long, 4–articulate, article 1 with 3 marginal setae on distolateral margin, article 2 longer than article 1, narrowing distally, with 2 clusters of 4 (medial) - 7 (lateral) distal marginal setae, article 3 long, 2.5x length of article 2, with 16–18 long - thin setae on medial margin; article 4 with 16–18 mixed long - short setae along distal half of medial margin, 6 submarginal setae (3 subequal to dactyl in length) on distal margin, inner surface with short, thin setae; dactyl well developed, with 7 short subapical setae, with unguis. Lower lip ( Fig. 2 F): bilobate, lobes subequal in length with multiple setae on surfaces and margins, apical end of each lobe with 3 small teeth.

Gnathopod 1 ( Fig. 3 A): simple; coxa slightly shorter than coxa 2, anterior margin concave, anteroventral corner produced forward, rounded, posterior margin slightly convex with 1 distal seta; basis long, wide, length 3.1x width, anterior margin lined with long setae, posterior margin smooth with cluster of long setae distally; ischium short, curved, length 1.2x width, long setae on posterior - anterodistal margins; merus subtriangular, shorter than ischium, long setae on posterodistal margin; carpus longer than merus, long setae on distal margin, anterodistal setae reaching distal end of propodus; propodus long, subrectangular, length 2.2x width, narrowing distally, distal margin with 6–7 short, continuous setae, 2/3 of posterior margin with 9+9 shortrobust and thin-long continuous setae, without palm; dactylus simple, slightly curved, 3 simple subterminal setae, weak unguis.

Gnathopod 2 ( Fig. 3 B): weakly subchelate; coxa long, slightly shorter than coxa 3, 2 short subterminal setae on posterior margin, 2 short submarginal setae on anterodistal margin; basis long (length 2.2x ischium), thin, curved, with a subterminal short seta on posterodistal margin, short setae on anteroproximal margin, anterodistal margin with short + long setae, 2 small teeth; ischium subrectangular, shorter than basis, length 2.8x width, long setae on distal margin; merus slightly curved, posterior margin with median row of numerous (20–25) short setae, cluster of long setae distally; carpus longer than merus (1.4x), geniculate, thin, with thin, long setae on outer surface, long setae subequal in length to propodus on distal margin, posterior margin convex, serrate in distal half, with subterminal cluster of long + short setae; propodus subrectangular (wider than long), setose over entire outer surface, distal setae slightly longer than length of propodus; palm obtuse, triangular, smooth, posterodistal corner without robust setae, toothed on posterior margin; dactylus lanceolate, longer than corner of palm.

Pereopods ( Figs. 3 C–G). Pereopod 3 ( Fig. 3 C): coxa long; basis longer than wide, anterior margin setose; ischium short, posterior margin setose; merus expanded distally, anterodistal margin produced forward with 4 short, strong spines, a long spine subequal to ½ length of carpus, posterior margin setose; carpus longer than wide (2.2x), posterior margin setose with cluster of 7 long setae on posterodistal margin; propodus thin, subequal in length to carpus, 6 long, continuous robust setae on posterior margin, a posterodistal robust seta; dactylus long, thin, with 1 plumose anteroproximal seta. Pereopod 4 ( Fig. 3 D): coxa slightly deeper than wide, posterior excavation deep, more than ½ length of posterior margin; basis longer than wide, anterior margin without setae; ischium short, posterior margin with long setae, 2 distal robust setae; merus expanded distally, anterodistal margin produced, with 2 long + 2 short robust seta, posterior margin setose; carpus widened distally, posterior margin setose, 1 posterodistal cluster of 7 subequal setae; propodus long, thin, subequal in length to carpus, 6 equidistant setae on posterior margin; dactylus thin, a plumose anteroproximal seta. Pereopod 5 ( Fig. 3 E): coxa with 2 distal lobes, both lobes subequal in size, posterior margin with 3 distal short setae; basis expanded, anterior margin with 12 short, subequidistant short-robust setae, 5 strong-long setae on anterodistal margin (1 longer than length of ischium), posterior margin slightly crenulated, with 6 short setae; ischium short, anterior margin with 3 robust setae on distal margin; merus expanded posteriorly, with 3–4 pairs of robust setae on anterior and posterior margins; carpus subequal in length to merus, distal- anterior margins setose; propodus long, thin, margins setose; dactylus with posteroproximal plumose seta. Pereopod 6 ( Fig. 3 F): coxa small, slightly bilobate distally; basis expanded posteriorly, with serrations - small setae on posterior margin, anterior margin with small setae, 3 small robust setae, 1 long, robust seta on anterodistal margin; ischium small, with 6 robust setae (3 long) on anterior margin, anterodistal margin with 1 long and 2 short robust setae; merus expanded, with posterior margin subtriangular, with 4 robust setae, anterior margin with 4 sets of 3 robust setae each; carpus longer than merus (0.5x), with evident robust seta on anterior - posterior margins, propodus thin, subequal in length to carpus, both margins setose; dactylus thin with 1 posteroproximal plumose seta. Pereopod 7 ( Fig. 3 G): coxa lobate posteriorly, with 6 small distal setae, posterodistal corner rounded; basis expanded posteriorly, with serrations - small setae on posterior margin, 9 minute distal setae on anterior margin, 4 robust setae (3 short + 1 long, subequal in length to ischium) on anterodistal margin; ischium short, with 4 anterodistal robust setae; merus slightly expanded posteriorly, with posterodistal margin subtriangular, setae on both margins; carpus thin, longer than merus, with setae on both margins, distal margin with 6 thick setae; propodus thin, long, margins with setae in equidistant pairs, distal margin with 1 cluster of 6 thin, long setae; dactylus thin with 1 posteroproximal plumose seta.

Pleonites 1–3 ( Fig. 1 A): dorsally smooth.

Epimeron 1–3 ( Fig. 4 B). Epimeron 1: anterior corner rounded, slightly convex posteriorly. Epimeron 2: ventral margin slightly rounded, posteroventral corner subrectangular. Epimeron 3: ventral margin linear, posterodistal corner rounded.

Uropods 1–3 ( Figs. 4 C–E). Uropod 1 ( Fig. 4 C): peduncle with 7 short outer marginal robust setae, 4 long inner marginal robust setae; rami subequal in length, outer with 4 short marginal robust setae, inner with 3 short marginal robust setae, 1 medial submarginal robust seta. Uropod 2 ( Fig. 4 D): peduncle proximally widened, with 4 outer marginal robust setae, 1 short inner marginal robust seta; rami subequal in length; outer with 4 long, robust marginal setae; inner with 1 short submarginal robust setae, 1 long, robust subdistal setae, a slight subdistal constriction. Uropod 3 ( Fig. 4 E): peduncle short, length 1.4x width, with dorsolateral flange, with 2 short, submedial robust setae, 1 distal robust seta, dorsal margin 2–crenulate, with 2 short robust setae, dorsodistal margin produced, with 1 robust subapical seta, ventrodistal margin with 1 apical robust seta; outer ramus slightly longer - robust than inner ramus, 2-segmented apically, article 2 short, poorly defined; inner ramus with 2 short submarginal setae ventrally.

Telson ( Fig. 4 F): slightly longer than wide, entire, distal margin straight, truncate, with 2 plumose setae on distolateral margins, 11 setae on dorsal surface, 2 submedian dorsal plumose setae.

Female unknown

Distribution. Veracruz Coral Reef System National Park, SW Gulf of Mexico, Mexico.

Remarks. Lysianopsis adelae n. sp., may be recognized and differentiated from all its co-genera by the following characteristics: eyes big, subrectangular; cephalic lobes long - pronounced; mandibular palp article 3 with 20–25 short marginal F3 setae; outer plate of maxilla 1 with 11 terminal setal-teeth in a 7/4 arrangement, each with 3–7 cusps (left), 3–9 cusps (right); maxilla 1 palp subrectangular distally; maxilliped inner plate with 9 pappose setae + 9 thin setae, telson with truncate distal margin, 2 plumose setae on corners of distal margin, 2 submedian plumose setae dorsally.

ozona , and L adelae n. sp. E. = Epistome; u.l. = upper lip.

Characteristics of the L. alba L. hummelincki L. ozona L. adelae n. sp.

male

A morphological comparison of the males of the Lysianopsis species made it possible to closely relate Lysianopsis adelae n. sp., with L. alba Holmes, 1903 , L. hummelincki ( Stephensen, 1933) and L. ozona Lowry & Stoddart, 1977 ( Table 1 ). The new species may be separated from these closely related species by the following characters: mandible with strong distal triturating surface on molar, outer plate of maxilla 1, setal teeth 4–6 with 3–4 small teeth, distal margin of telson rounded (vs L. alba ); epistome linear, upper lip subrectangular, gnathopod 1 prehensile, uropod 3 with outer ramus 1-articulate (vs L. hummelincki ); outer plate of maxilla 1, setal teeth 4–6 with 8–10 small teeth, gnathopod 1 not prehensile, palm of gnathopod 2 slightly obtuse with serrated margin, dactylus does not reach corner of palm, outer ramus of uropod 2 biarticulated strongly, distal margin of telson truncated with terminal spines (vs L. ozona ).

Figures

FIGURE 1. Lysianopsis adelae n. sp. Habitus of male holotype, lateral view.

FIGURE 2. Lysianopsis adelae n. sp. Male holotype. A, epistome and upper lip; B, mandible with details of article 3; C, maxilla 1 with details of distal margin of outer plate, palp, and ST 7 from opposite MX 1; D, maxilla 2; E, maxilliped with details of apical nodular setae; F, lower lip.

FIGURE 3. Lysianopsis adelae n. sp. Male holotype. A, gnathopod 1; B, gnathopod 2 with details of dactylus and palm; C, pereopod 3; D, pereopod 4; E, pereopod 5; F, pereopod 6; G, pereopod 7.

FIGURE 4. Lysianopsis adelae n. sp. Male holotype. A, head with antenna 1 and 2, and details of aesthetascs; B, epimeron 1 – 3; C, uropod 1; D, uropod 2; E, uropod 3; F, telson.

Tables

TABLE 1. Comparison of morphological features of 4 species of the genus Lysianopsis: L. alba, L. hummelincki, L.

Eyes	Moderate, subcircular	Big, subcircular	Big, suboval	Big, subrectangular
Epistome, upper lip	E. concave; u.l. subacute, produced forward further than E.	E. narrow, linear; u.l. subrectangular, produced forward further than E.	E. narrow, concave; u.l. rounded, produced forward slightly further than E.	E. narrow, slightly concave; u.l. subquadrate, produced forward slightly than E.
Mandible	Molar developed, curved distally, partly setose, strongly spiny	Molar developed, partly setose, with slightly triturative distal surface	Molar developed, similar to a setose tongue with vestigially triturative distal surface	Molar developed, similar to a setose tongue with vestigially triturative distal surface
Maxilla 1	Outer plate with ST4-6 with 3–4 small teeth	Outer plate with ST4-6 with 3–4 small teeth	Outer plate with ST4-6 with 8–10 small teeth	Outer plate with ST4-6 with 4–7 small teeth
Gnathopod 1	Slightly prehensile, (apparently slightly falcate)	Prehensile (apparently falcate)	Not prehensile (not falcate)	Slightly prehensile (slightly falcate)
Gnathopod 2	dactylus not reaching palmar angle	Palm slightly obtuse, margin convex and smooth; dactylus not longer than palm	Palm slightly obtuse, margin convex and serrate; dactylus does not reach corner of palm	Palm obtuse and triangular, margin smooth; dactylus longer than corner of palm
Uropod 3	Outer ramus 2-articulate with article 2 slightly defined	Outer ramus 1-articulate	Outer ramus 2-articulate with article 2 clearly defined	Outer ramus 2-articulate with article 2 slightly defined
Telson	Distal margin rounded, without robust apical setae, with 2 short and thin setae (without terminal spines)	Distal margin rounded, with 2 short and thin apical setae (without terminal spines)	Distal margin truncate, with 2 long and robust apical setae (with terminal spines)	Distal margin truncate, with 2 thin apical brush setae (without terminal spines)