Victoriopisa cangio, Marin & Palatov, 2022

Marin, Ivan N. & Palatov, Dmitry M., 2022, Two new species of the genus Victoriopisa Karaman & Barnard, 1979 (Crustacea: Amphipoda: Eriopisidae) from mangrove communities of Vietnam with a review of previous records, Zootaxa 5094 (1), pp. 129-152 : 142-149

Victoriopisa cangio sp. nov.

Figs 2–4 , 12 b

Material examined. Holotype, ovigerous ♀ (bl. 7.5 mm), ZMMU Mb- 1219— VI ỆT NAM, Ho Chi Minh District, Cần Gi ớ Mangrove Biosphere Reserve , 10°27’19.1”N 106°53’32.9”E, soft muddy bottom, along the banks of canals deep in mangroves, coll. I. Marin & S. Sinelnikov, 25 April 2020.

Etymology. The new species is named after the Cần Giớ Mangrove Biosphere Reserve, where it was discovered.

Description. Based on holotype female (ZMMU Mb-1219).

Body ( Fig. 2 с): body length 7.5 mm, with few small separate setae on dorsal surface of pereonites and urosomites, urosomites free.

Head: slightly wider than first pereonite, anteroventral margin entire, without anteroventral sinus; eyes present ( Fig. 8 c ).

Antenna 1 ( Fig. 8 a ): about as long as body length; length ratio of peduncular articles 1–3 close to 1.0:1.1:0.3, article 1 with tuft of long simple setae distodorsally, article 2 with 5 groups of long setae distodorsally; article 3 with single setae distodorsally; primary flagellum at least with 14 articles, each with distal setae, aesthetascs present on articles 6–14; accessory flagellum 2-articulated ( Fig. 8 b ), about as long as article 1 of primary flagellum, with 3 long distal simple setae.

Antenna 2 ( Fig. 8 c ): about 1/3 of the length of antenna I; with ratio of lengths of peduncular articles 3–5 close to 1:1.9:2.0; flagellum short, consists of 2 fused long articles and 3 short articles, reaching 0.70 times as long as peduncular article 5, with setae along the margins.

Upper lip ( Fig. 9 a ): oval, bearing fine setae dorsally.

Lower lip ( Fig. 9 b ): inner lobes well developed, with fine setae; outer lobes with small dense apical setae.

Mandible ( Fig. 9 c–f ): left incisor ( Fig. 9 c ) with 5 teeth; lacinia mobilis with 4 teeth; accessory setal row consisting of 6 serrated setae and several fine setae ( Fig. 9 d ); molar columnar; palp with 3 articles in length ratio of 1.0:4.1:4.3, article 3 equal to article 2, armed with 4 long simple D-setae and 7 long distal E-setae, article 2 with 1 seta on medial margin ( Fig. 9 c ). Right mandible ( Fig. 9 e ): incisor and lacinia mobilis with 3 teeth; accessory setal row composed of 7 serrated setae ( Fig. 9 f ); molar with a longer seta; general proportions similar to the left mandible.

Maxilla 1 ( Fig. 9 g ): inner plate with 10 plumose setae and a simple seta; outer plate with 9 serrated apical spines ( Fig. 9 h ); palp 2-articulated, article 2 with 3 stout spines distinctly, 5 stiff setae, 1 large distal and 1 subdistal setae.

Maxilla 2 ( Fig. 9 i ): inner plate with 11 plumose setae in oblique row and simple setae on apical margin; outer plate with 8 slender simple setae and a few fine setae on apical margin.

Maxilliped ( Fig. 9 j ): inner plate with 3 stout apical spines, 12 plumose setae, 3 stiff setae on apical margin; outer plate about twice longer than inner plate, with number of simple setae on apical and lateral margin; palp 4-articulated, article 2 with convex inner margin covered with numerous simple setae, article 3 subovate, with several groups of facial setae, article 4 rather claw-like with 1 seta on outer margin and 2 small simple setae on inner margin.

Coxal gills: present on gnathopod 2 and pereopods 3–6; gills of gnathopod 2 ( Fig. 8 f ) and pereopods 3–5 longer than basis of corresponding pereopods ( Fig. 10 a, c, e ), gill 6 much shorter than basis of pereopod 6 ( Fig. 10 g ).

Oostegite ( Figs 8 f , 10 a, c, e ): present on gnathopod 2 and pereopods 3–5, slender, longer than width, with numerous long simple setae on margins.

Gnathopod I ( Fig. 8 d ): subchelate, significantly smaller than gnathopods 2; coxal plate subrectangular with straight ventral margin, posteroventral corner notch absent; basis expanding distally, about 3.5 times as long as distal width, with 5 groups of double setae, several short and long simple setae on posterodistal corner; ischium as long as wide, smooth; merus slightly longer than wide, without anterodistal swelling, with 5 large subdistal setae; carpus about 2.7 times as long as wide, with 5 double-rows of long simple setae along posterior margin; propodus (palm) with significantly projected distoventral corner and anterior margin, with 5 spines on posterodistal corner, 3 simple setae along medial side, and 9 short spines along palmar margin; dactylus curved, robust, with 1 simple seta on posterior margin.

Gnathopod 2 ( Fig. 8 f, g ) subchelate; coxal plate ovoid, wider than length, with 3 small thin setae on anterodistal corner, with convex ventral margin, posteroventral corner notch absent; basis longer than ischium, merus and carpus, expanding distally, about 3.0 times as long as distal width, with straight median lateral margins, with 8 simple setae on posterior margin and 4 long simple setae on posterodistal corner; ischium as long as wide, smooth; merus subquadrate slightly longer than wide, posterior median surface slightly convex and smooth; carpus triangular, lobed, about as long as wide, with 5 rows of long simple setae along posterior margin; propodus (palm) ( Figs 3 g , 7 e ) elongated, teardrop-shaped, about 1.6 times as long as maximal width, anterodistal corner convex, slightly setose; palmar margin composed of 1 lobe, 2 excavations and 2 large medial robust setae, lobe with small lateral robust spine-like setae ( Fig. 12 b ); dactylus stout, strongly curved, ventral margin with deep median excavation and proximal lobe (protrusion), with straight sharp tip.

Pereopod 3 ( Fig. 10 a ): slender; coxal plate subrectangular, about twice wider than length; basis linear, with straight median margins, about 3.5 times as distal width, with smooth anterior margin, 10 long setae on posterior margin and 2 long simple setae on posterodistal corner; ischium as long as wide, smooth; merus about 2.3 times as long as maximal width, with anterior margin protruding forward, armed with 2 anterodistal setae, with 3 setae on distal part of posterior margin; carpus elongated, about 2.9 times as long as wide, with 3–4 simple setae on anterior margin and 7 separate and grouped long setae on posterior margin; propodus about 5.8 times as long as wide, linear with straight margins, with 4 long simple setae on anterior margin, with 4 small spines accompanied by groups of setae along posterior margin and 1 spine on posterodistal corner; dactylus ( Fig. 10 b ) long, slender and curved, about 6 times as long as the width, with a penicillate seta on anteroproximal margin and 1 fine seta subdistally.

Pereopod 4 ( Fig. 10 c ): almost similar to pereopod 3; coxal plate subrectangular, about twice wider than length; basis linear, with straight median margins, about 3.5 times as distal width, with smooth anterior margin, 10 long setae on posterior margin and 2 long simple setae on posterodistal corner; ischium as long as wide, with 1 long seta on posterodistal corner; merus about 2.3 times as long as maximal width, with anterior margin protruding forward, armed with 2 anterior setae, 2 anterodistal setae, and with 2 double setae on posterior margin; carpus elongated, about 2.7 times as long as wide, with 3 setae anterior margin and 2 setae on anterodistal corner, with 4 double setae on posterior margin; propodus about 6 times as long as wide, linear with straight margins, with 3 long spines on anterior margin, with 4 long thin spines accompanied by groups of setae along posterior margin and 1 spine on posterodistal corner; dactylus ( Fig. 10 d ) long, slender and curved, about 7.5 times as long as wide, with a penicillate seta on anteroproximal margin and 1 fine seta subdistally.

Pereopod 5 ( Fig. 10 e ): stout; coxal plate bilobate, about 2.6 times as long as wide, anterior lobe with 3 small setae on ventral margin; basis linear oblong, about 2.1 times as long as wide, with 4 and 7 small setae on anterior and posterior margins, respectively, and 2 long setae on anterodistal corner; ischium as long as wide, with 2 long setae on anterodistal corner; merus about 2.2 times as long as wide, posterior margin just slightly protruding forward, with 2 spines on posterior margin, 1 large spine-like seta accompanied by several small setae on posterodistal corner, with 3 groups of long setae on anterior margin and 2 large spine-like setae accompanied by several small setae on anterodistal corner; carpus shorter than merus, about 2.8 times as long as wide, linear, with straight lateral margins, without long setae on posterior margin and 3 long double setae on anterodistal corner, with 4 large spine-like setae on posterodistal corner; propodus linear, slender, about 4.4 times as long as wide, with straight lateral margins, with 2 small spines accompanied by long setae on anterior margin and 1 spine accompanied by some setae on anterodistal corner, posterior margin smooth, unarmed, with 4 long strong spine and several small seta on posterodistal corner; dactylus ( Fig. 10 f ) slender, curved, about 5.5 times as long as wide, about twice shorter than the longest spines on posterodistal corner of propodus, with 1 penicillate seta on posteroproximal margin and 1 seta subdistally.

Pereopod 6 ( Fig. 10 g ): longer than pereopod 5; longer than pereopod 5; coxal plate shallow, bilobate, anterior lobe with 3 small setae on ventral margin; basis dilated, expanded in proximal part, about 1.7 times as long as maximal width, with 5 setae on anterior and 1 long simple setae accompanied with several small setae on anterodistal corner, with 6 small setae on posterior and 1 long simple submarginal seta on posterodistal corner; ischium as long as wide, with 2 long setae on anterodistal corner; merus about 2.5 times as long as wide, posterior margin just slightly expanded and protruding forward, with 2 spine-like setae on anterior margin, 1 large spine-like seta on anterodistal corner, with 2 spine-like setae on posterior margin and 1 strong spine on posterodistal corner; carpus shorter than merus, about 3.9 times as long as wide, linear, with straight lateral margins, with 2 groups of long simple setae on anterior margin and 4 long simple setae on anterodistal corner, without setae on posterior margin and 3 large setae on posterodistal corner; propodus linear, slender, about 6.5 times as long as wide, with straight lateral margins, with 2 double long spine on anterior margin and 2 spines accompanied by some setae on anterodistal corner, posterior margin smooth, unarmed, with 3 long and several small seta on posterodistal corner; dactylus slender, curved, about 7 times as long as wide, about twice shorter than the longest spines on posterodistal corner of propodus, with 1 penicillate seta on posteroproximal margin and 1 seta subdistally.

Pereopod 7 ( Fig. 10 h ): coxal plate small, suboval, about 2.2 times as long as maximal width, with 1 seta on posterodistal corner; basis expanded posteriorly, progressively wider towards posterodistal, about 1.3 times as long as wide, with 5 and 14 small spines on anterior and posterior margins, respectively, with 3 long setae on anterodistal corner; ischium slightly wider than long; merus expanded posteriorly, with 2 small spines accompanied with long setae and 1 simple seta on anterior margin and 2 long spine-like setae on anterodistal corner, with 4 strong spines on posterior margin and 1 strong spine on posterodistal corner; carpus shorter than merus, linear, about 3.6 times as long as wide, with straight lateral margins, with 2 groups of long simple setae on anterior margin and 3 long simple setae on anterodistal corner; posterior margin smooth, with 1 small seta and 2 strong spine-like setae on posterodistal corner; propodus linear, slender, about 4.2 times as long as wide, with straight lateral margins, with 2 pairs of spinelike setae on anterior margin and 2 long spines accompanied by several small setae on anterodistal corner, posterior margin smooth, unarmed, with 1 small seta and 2 long and 1 medium spine-like setae on posterodistal corner; dactylus ( Fig. 10 h ) slender, curved, about 5.2 times as long as wide, with 1 penicillate seta on posteroproximal margin and 1 seta subdistally.

Epimeral plates: plate 1 ( Fig. 11 a ) bare, with 2 small setae on posterior margin, posteroventral corner without projection; plate 2 ( Fig. 11 b ) with 8 long setae on ventral margin and 3 small setae along posterior margin, posteroventral corner without projection; plate 3 ( Fig. 11 c ) with 2 submarginal setae on ventral margin, and 2 small setae on posterior margin, posteroventral slightly projected posteriorly.

Pleopods 1–3 ( Fig. 11 e, g ): peduncles nearly quadrate, with 2 coupling hooks in retinacula on inner margins ( Fig. 11 f ), outer margins with 7 plumose setae in pleopod 1 ( Fig. 6 e ), 5 plumose setae in pleopod 2, and without plumose setae in pleopod 3 ( Fig. 6 g ); inner and outer rami fringed with plumose setae.

Uropod 1 ( Fig. 11 h ): peduncle stout, about 4.0 times as long as wide, slightly longer than rami, with 1 large submarginal ventroproximal spine, 3 spines on outer and inner margin, 1 large and 1 small spines on both outer and inner distal corners, respectively; outer ramus as long as inner ramus, about 10 times as long as wide, with 4 long simple spines on outer margin and 4 terminal spines distally, inner margin unarmed; inner ramus about 8.4 times as long as wide, with 3 spines on outer margins and without spines on inner margins, 3 large and 1 small terminal spine distally.

Uropod 2 ( Fig. 11 i ): about 0.5 times as long as uropod I; peduncle relatively stout, about twice as long as wide, with 2 spines on outer margin and 2 spines on outer distal corner; outer ramus about as long as peduncle, equal to inner ramus, with 1 spine on outer margin and 2 spines on inner margin, with 4 stout terminal spines; inner ramus with 2 spines on outer margin and 2 submarginal spine on inner margin, with 4 stout terminal spines.

Uropod 3 ( Fig. 11 j ): much enlarged, about 2.2–3 times longer than other uropods; peduncle about 1.9 times as long as wide, about 0.4 of the length of proximal article of outer ramus, with 2 pairs of small spines on outer margin and 1 submarginal pair on inner margin, 3 spines accompanied by small setae on outer distal corner, and 5 spines on inner distal corner; inner ramus small, scale-like, about 0.08 times as long as outer ramus, and twice smaller than peduncle, with 2 small spines distally; proximal article of outer ramus with 5 small spine-like setae on outer margin, 6 groups and 2 separate spines on inner margin, 2 groups of spines on facial surface, 3 spines and several long setae on outer distal corner, and 4 spines and several long setae on inner distal corner, terminal article of outer ramus sub-oval, about 5.3 times as long as wide, slightly shorter than proximal article, with 3 small spine-like setae on outer margin, 5 small spines accompanied by setae on inner margin, 1 group of submarginal facial setae and 16 long slender terminal setae apically.

Telson ( Fig. 11 d ): about 0.9 as long as wide, cleft almost reaching base; lobe subovate, with 1 large subdistal spine-like setae, accompanied with 1 small setae and 2 pairs of long penicillate setae on dorsal surface.

Coloration. Body coloration of alive animals varies from completely white to light yellow (see Fig. 2 c ).

Body size. The largest collected female has bl. 7.5 mm.

Habitat and ecology. The single specimen of the new species was collected when washing a heavily silted substrate from a small pond fenced off from a channel overgrown with mangroves.

Distribution. Presently known only from the type locality, the Cần Giớ Mangrove Biosphere Reserve, Soài Rạp River delta, South Việt Nam ( Fig. 1 ).

Taxonomic remarks. The new species, similar to Victoriopisa nhatrangensis sp. nov., is characterized by the presence of a weakly but developed eyes and deep excavation on dactylus of gnathopod 2, which also present only in V. chilkensis and V. bruneiensis (see above).

Among them, V. bruneiensis is characterized by the absence of a tuft of setae on distodorsal margin of article 2 of antenna I and significantly expanded distoventral margin of gnathopod I, which is also characteristic to Victoriopisa cangio sp. nov., showing that these species is obviously closely related. At the same time, it can be separated by longer accessory flagellum of antenna 1 reaching the distal margin of article 1 of the main flagellum (vs. not reaching in V. cangio sp. nov.), the presence of a dense facial setation of merus of gnathopod 1, which is absent in V. cangio sp. nov., different armature of ventral margin of propodus (palm) and deeply developed excavation on the dactylus of gnathopod 2, different proportions of pereopod 3–7, especially slender merus of pereopod 5 and less expanded basis of pereopod 7, stouter uropod 2 and less expanded proximal part of telson.

Victoriopisa nhatrangensis sp. nov. can be clearly separated from Victoriopisa cangio sp. nov. by the absence of a tuft of setae on distodorsal margin of article 2 of antenna 1, the presence of a dense facial setation of merus and not anteriorly expanded distoventral margin of propodus (palm) of gnathopod 1, different shape and armature epimeral plates and telson, proportion and armature of uropods 2–3.

Figures

FIGURE 1. The map of distribution of freshly collected species and Victoriopisa ovata (Dan & Le, 2005) (above) as well as the characteristic biotope in the Cần Giớ Mangrove Biosphere Reserve (below), where crustaceans were sampled.

FIGURE 2. General view (habitus) and live coloration of the described representatives of the genus Victoriopisa Karaman & Barnard, 1979: a—Victoriopisa nhatrangensis sp. nov., habitus, paratype ♀♀, ZMMU Mb-1218; b—head of Victoriopisa nhatrangensis sp. nov., c—live coloration of Victoriopisa cangio sp. nov., holotype, ZMMU Mb-1219, ovigerous ♀.

FIGURE 3. Victoriopisa nhatrangensis sp. nov., holotype ♀, ZMMU Mb-1217 (a–f), paratype ♀, ZMMU Mb-1218 (g): a— antenna 1; b—accessory flagellum of antenna 1; c—antenna 2; d—gnathopod 1; e—distoventral palmar margin of chela of Gn2; f—gnathopod 2; g—distoventral palmar margin of chela of Gn2.

FIGURE 4. Victoriopisa nhatrangensis sp. nov., holotype ♀, ZMMU Mb-1217: a—labrum (upper lip); b—labium (lower lip); c—left mandible; d—same, incisor process and pars incisiva; e—right mandible; f—same, incisor process and pars incisiva; g—maxilla 1; h—distal margin of inner plate of maxilla 1; i—maxilla 2; j—maxilliped.

FIGURE 6. Victoriopisa nhatrangensis sp. nov., holotype ♀, ZMMU Mb-1217: a—epimeral plate 1; b—epimeral plate 2; c—epimeral plate 3; d—telson; e—pleopod 2; f—hooks of retinacula of pleopod 1; g—uropod 1; h, i—uropod 2; j– uropod 3.

FIGURE 7. Victoriopisa nhatrangensis sp. nov., ♀ (dissected) (LEMMI): a—accessory flagellum of antenna 1; b—antenna 2; c—same distal segment; d—chela of gnathopod 1; e—chela of gnathopod 2; f—urosomal segments; g—coupling hooks of uropod 2. Sacle 0.2 mm.

FIGURE 8. Victoriopisa cangio sp. nov., holotype ♀, ZMMU Mb-1219: a—antenna 1; b—accessory flagellum of antenna 1; c—antenna 2; d—gnathopod 1; e—distoventral palmar margin of chela of Gn2; f—gnathopod 2; g—spines of distoventral palmar margin of chela of Gn2; h—ventral margin of dactylus of Gn2.

FIGURE 9. Victoriopisa cangio sp. nov., holotype ♀, ZMMU Mb-1219: a—labrum (upper lip); b—labium (lower lip); c—left mandible; d—same, incisor process and pars incisiva; e—right mandible; f—same, incisor process and pars incisiva; g—maxilla 1; h—distal margin of inner plate of maxilla 1; I—maxilla 2; j—maxilliped.

FIGURE 10. Victoriopisa cangio sp. nov., holotype ♀, ZMMU Mb-1219: a—pereopod 3; b—dactylus of P3; c—pereopod 4; d—dactylus of P4; e—pereopod 5; f—dactylus of P5; g—pereopod 6; h—pereopod 7; i—dactylus of P7.

FIGURE 11. Victoriopisa cangio sp. nov., holotype ♀, ZMMU Mb-1219: a—epimeral plate 1; b—epimeral plate 2; c—epimeral plate 3; d—telson; e—pleopod 1; f—hooks of retinacula of pleopod I; g—pleopod 3; h—uropod 1; i—uropod 2; j—uropod 3.

FIGURE 12. Distoventral (palmar) margins of propodus (palm) of pereopod 2 (cheliped): a—Victoriopisa nhatrangensis sp. nov., holotype ♀, ZMMU Mb-1217; b—Victoriopisa cangio sp. nov., holotype ♀, ZMMU Mb-1219.