Wolffogebia cangioensis Kolevatov & Marin 2022, sp. nov.
Creators: name: Kolevatov, Vasily
name: Marin, Ivan
Publisher: name: Zenodo
Year: 2022
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Malacostraca
Decapoda
Upogebiidae
Wolffogebia
Wolffogebia cangioensis

description: Wolffogebia cangioensis sp. nov.
(Figs 1–7)
Wolffogebia inermis.— Ngoc-Ho, 1994b: 213, figs 10e-f, 11.
Type material. Holotype, ♂ (cl. 5.5 mm, bl. 18 mm), ZMMU Ma-6222— VIETNAM, Ho Chi Minh District, Cần Gi ớ Mangrove Biosphere Reserve, 10°27’35.6”N 106°53’38.2”E, in burrows in the mud banks of canals deep in mangroves, yabby-pump sampling, coll. I. Marin & S. Sinelnikov, 25 April 2020. Paratypes: 1 ovigerous ♀ (dissected) (cl. 5.7 mm, bl. 18mm), ZMMU Ma-6223; 1 ♂ (dissected) (cl. 6.0 mm, bl. 18 mm), ZMMU Ma-6224— same locality as for holotype.
Additional material. 5 ovigerous ♀♀, 7 non-ovigerous ♀♀, 6 ♂♂, LEMMI — VIETNAM, Ho Chi Minh District, Cần Gi ớ Mangrove Biosphere Reserve, 10°27’35.6”N 106°53’38.2”E, inside manually excavated burrows and sampling with yabby-pump, coll. I. Marin & S. Sinelnikov, 27–30 April 2020.
Etymology. The new species is named after the Cần Giớ Mangrove Biosphere Reserve, where it was discovered.
Description. Rostrum (Fig. 2 a–c) relatively long, reaching the distal margin of article 3 or midlength of antennal peduncle article 4, about 2.3 times as long as broad at base, bluntly rounded distally in dorsal view, straight or slightly turned downward in lateral view; dorsal surface fringed with dense mat of short setae; ventral surface rounded, unarmed. Anterior carapace (Fig. 2 a–c) dorsally flattened, fringed with dense mat of short setae, without any groove, ridges or carinae; anterolateral border of carapace smooth and unarmed; lateral surface weakly concave. Posterior carapace (Fig. 1) with shoulder lateral to cervical groove unarmed; linea thalassinica reaching posterior margin of carapace.
Pleuron (Fig. 1) of pleomere 1 poorly developed, pleuras of pleomeres 2–5 rather well developed, ventrally smooth; tergum of pleomeres 2–5 smooth, unarmed; pleomeres 3–5 with dense fringe of short plumose setae. Pleomere 6 (Fig. 2 f, g) slightly broader than long, almost quadrate, lateral margins concave at midlength; tergum smooth, without grooves.
Telson (Fig. 2 g) subquadrate, slightly longer than broad, with shallow longitudinal median groove, reaching the distal margin; with pair of subcircular bulges armed with clusters of simples setae proximal to median groove; posterior margin slightly concave, with or without median triangular tooth.
Eyestalk (Fig. 2 a-c) stout, slightly upturned, unarmed; cornea terminal, darkly pigmented, narrower than diameter of eyestalk and directed anterolaterally.
Antennula (Fig. 2 d) with peduncle reaching distal margin of article 3 or midlength of article 4 of antennal peduncle; article 1 (basal) stout, about as long as wide, fringed with plumose setae; article 2 small, as long as wide, with several long plumose setae along inner lateral margin; article 3 long, slender, about 7 times as long as wide, equal in length to article 1 and article 2 together, with long simple setae along inner lateral margin.
Antenna (Fig. 2 e) with peduncle overreaching rostrum, with unarmed articles, proportion of articles is close to 1.0:2.0:3.0:1.5. Scale subtriangular, terminating in acute point.
Mandible (Fig. 3 a, b) with row of very smal1 sharp triangular teeth on cutting edge (mesial margin) of incisor process; palp composed of 3 broad articles, fringed with dense row of plumose marginal setae.
Maxillule (Fig. 3 c) with recurved endopod; coxal endite large, with somewhat produced distomesial angle and broadly rounded proximolateral lobe; basial endite broadened distally, with small corneous spines on mesial margin.
Maxilla (Fig. 3 e) with moderately broad scaphognathite, fringed with plumose setae; endopod is visible in ventral view, with rounded tip; coxal endite divided into unequal lobes, distal lobe large, widening distally, with sinuous line of medium plumose setae on ventral surface, proximal lobe narrow, tapering distally; basial endite is simple, distinctly broader than distal lobe of coxal endite.
Maxilliped 1 (Fig. 3 d) with large triangular epipod, blunt distally; exopod slightly expanded at distolateral angle, entire lateral margin fringed with row of long setae, with short entire flagellum; flagellum small, non-articulated, fused with basal part; endopod reaching base of exopodal flagellum (Fig. 4 a–d).
Maxilliped 2 (Fig. 3 f) with small epipod; exopod slender, without flagellum; endopod pediform, composed of 6 articles, basis and ischium fused; merus broad, fringed with dense row of marginal setae; dactylar article with dense tuft of strong submarginal setae (Fig. 4 e).
Maxilliped 3 (Fig. 3 g) moderately stout, lacking epipod; exopod short, reaching distal margin of ischium, flagellum small, non-articulated, fused with basal part (Fig. 4 f).
Pereopod 1 (cheliped) in males (Fig. 5) moderately stout, subchelate, all articles fringed with long setae along ventral margin; coxa unarmed, about 1.4 times as long as wide; basis short, unarmed (Fig. 5 a, d); ischium with 1 strong sharp spine distoventrally; merus about 1.5 times as long as wide, with 1 strong sharp spine on proximal ventral margin, dorsal margin slightly convex in its medial part, armed with slender sharp subdistal spine; carpus (Fig. 5 c, f) triangular, about as long as wide, without any groove or carina, with 1 strong spine at ventrodistal angle and 2 strong spines at dorsomesial margin; palm (propodus) about 2.2 times as long as high, dorsodistal margin with 2 large triangular spines, dactylar condyle on lateral face prominent, bluntly produced, lateral and mesial face smooth, unarmed, distoventral margin with 1 large spine arising ventromesialy beside large fixed finger (Fig. 5 b, e); dactylus slender, relatively long, about 0.8 of propodus (palm) length, distally slightly curved, smooth, dorsal (extensor) surface slightly concave fringed with a row of long simple setae, outer dorsoproximal part with 3–4 blunt tubercles, lateral and mesial face smooth, ventromesial part concave, cutting edge with mesial oblong protrusion. Pereopod 1 (cheliped) in females (Fig. 6) generally similar to those of males, but with more slender articles,; coxa unarmed, short; basis short, unarmed (Fig. 6 a, d); ischium with 1 relatively small spine distoventrally; merus about 3 times as long as wide, with 1 strong sharp spine on proximal ventral margin, dorsal margin slightly convex in its medial part, armed with slender subdistal spine; carpus (Fig. 6 c, f) triangular, about 2 times as long as wide, without any groove or carina, with 1 strong spine at ventrodistal angle and 2 strong spines at dorsomesial margin; palm (propodus) about 3.5 times as long as high, dorsodistal margin with 1 large triangular spine, dactylar condyle on lateral face feebly developed, lateral and mesial face smooth, unarmed, distoventral margin with 1 relatively small curved spine (Fig. 6 b, e); dactylus slender, relatively long, about 0.8 of propodus (palm) length, distally slightly curved, smooth, dorsal (extensor) surface slightly concave fringed with a row of long simple setae, lateral and mesial face smooth, ventral margin smooth and unarmed, ventromesial part concave.
Pereopod 2 similar both in males (Fig. 5 g, h) and females (Fig. 6 g, h), reaching base of dactylus of first pereopod; coxa and basis small, unarmed; ischium unarmed, about as long as wide; merus about 3 times as long as wide, with strong proximal spine on ventral margin and small subdistal spine on dorsal margin; carpus triangular, about as 1.5 times as long as wide, with small subdistal spine on dorsal margin; propodus about 1,8 times as long as high, unarmed; dactylus triangular, with oblique dorsolateral surface fringed with row of long simple setae.
Pereopod 3 (Figs 5 i, 6 i) with unarmed smooth coxa, gonopore situated at top of short projection in females, males rarely with small, gonopore-like structure on mesial face; basis short and unarmed; ischium unarmed, slightly longer than wide; merus unarmed on dorsal and ventral margins, about 3 times as long as wide; carpus subtriangular, about 2 times as long as wide, unarmed; propodus unarmed, about 2.5 times as long as wide; dactylus equal to propodus, twisted, ventral margin smooth, unarmed.
Pereopod 4 (Figs 5 j, 6 j) with unarmed articles, without specific features; dactylus slender, longer that propodus, somewhat twisted, ventral margin smooth and unarmed.
Pereopod 5 (Figs 5 k, 6 k) subchelate, articles unarmed, without specific features; propodus subequal in length to carpus, without or with reduced fixed finger; dactylus somewhat curved, about 0.4 of propodus.
Pleopod 1 uniramous in females and absent in males; pleopods 2–5 with oval endopod, without specific features.
Uropod (Fig. 2 f, g) exceeding posterior margin of telson; protopod unarmed; exopod with 2 dorsal and 1 lateral carinae, lateral margin straight and smooth, posterior margin slightly concave, smooth; endopod with 1 lateral and 1 median carinae, anterolateral angle bluntly produced; posterior margin straight, smooth.
Gill formula is presented below (see Fig. 7).
Ovigerous females carrying relatively large, globular eggs of about 0.5–0.6 mm in diameter.
Size. Carapace length (cl.) is up to 8 mm in males and 5–6 mm in ovigerous females; maximal body length (bl.) is about 18–20 mm, males are usually larger than females.
Coloration in life. Coloration is as for other species of the genus and generally representatives of the family Upogebiidae. The body and appendages are translucent whitish, somewhat bluish on uropods and pereopods 1 (chelipeds); cornea is bright white; yellowish internal organs are visible through the translucent integuments of the carapace; eggs are yellow (Fig. 1).
GenBank accession numbers. OP381657, OP381658.
Habitat and ecology. The shrimps were collected during the day using a hand pump (yabby-pump) from small (5–7 cm depth) burrows in mud near the mangroves. At night, the shrimps go out into the water column, where their mass swarming occurs. At this moment, it is possible to catch them with a hand net in large numbers. Interestingly, in the water column at night, it is possible to find ovigerous females, and therefore such swarming is not related to mating, but rather feeding behavior. During the daytime, mud shrimps can only hide in short vertical burrows, which they probably dig immediately after settling on the bottom. We assume that it is impossible to create a flow of water for feeding in such small temporal burrows, which is characteristic for many representatives of the family Upogebiidae (e.g., Marin & Antokhina, 2020), and they are used only for shelter during the daytime.
Distribution. The species is currently known only from the delta of Soài Rạp River in the Cần Giớ Mangrove Biosphere Reserve, South Vietnam.
Taxonomical remarks. The genus Wolffogebia K. Sakai, 1982 presently includes six valid species (WoRMS, 2021), which can be divided into two taxonomic groups. The first group, namely W. phuketensis, W. nhatrangensis and W. giralia, includes the species with dorsal tubercles on rostrum and large fixed finger of pereopod 1 in females, while the second group, namely W. heterocheir, W. annandalei, W. inermis and Wolffogebia cangioensis sp. nov., includes the species with dorsally smooth rostrum and small or mostly reduced fixed finger of pereopod 1 (cheliped) in females. The phylogenetic monophyly of the second group of species is supported by molecular-genetic data (see Fig. 9).
The new species can be separated from W. inermis by 1) longer rostrum, which is about 2.5 times as long as wide in the new species (see Fig. 2 c) (vs. about as long as wide (Fig. 8 a, b; Sakai, 1982: fig. 17c; Sakai, 1993: fig. 12A)); 2) flagellum of exopod of maxillipeds 1 and 3 with fused articles in the new species (see Fig. 4 c–f) (vs. exopods with 2–4-articled flagellums on maxillipeds 1 and 3 (Sakai, 1993: Fig. 13)); and 3) the armature of propodus and dactylus of pereopod 1 (chelipeds) (see Figs 5, 6) (vs. Fig. 8 c–f; Sakai, 1993: Fig. 20). Propodus of pereopod 1 (cheliped) in males in the new species with 2 strong spines at dorsomesial margin in the new species (see Fig. 5 a–b) (vs. only 1 strong spine and a blunt projection (see Fig. 8 c–f; Sakai, 1982: Fig. 20 (for holotype)); distoventral margin with 1 spine beside fixed finger (see Fig. 5 e) (vs. only a large curved fixed finger (without additional spines) (Fig. 8 c, d, f; Sakai, 1982: 20)); dactylus of pereopod 1 (cheliped) in males without dorsoproximal blunt projection and mesial lateral spine (see Fig. 5 b, e) (vs. such structures present in W. inermis (Fig. 8 d, f )).
From W. heterocheir, the new species can be separated by 1) unarmed articles of antennal peduncle (Fig. 2 e) (vs. armed articles 2 and 3 (see Kemp, 1915: 22 b)); 2) the length of uropodal exopod significantly exceeding that of endopod (see Fig. 2 f, g) (vs. endopod and exopod are equal in length (see Kemp, 1915: pl. XIII, 7)); and 3) the armature of pereopod 1 (chelipeds): the propodus of cheliped in males of the new species armed with 1 strong large lateral spine distoventrally, which is equal to fixed finger (Fig. 5 e) (vs. 1 small lateral spine (see Kemp, 1915: Fig. 23)); dorsal margin of the propodus in the new species with 2 large subdistal spines (Fig. 5 a–b) (vs. 2 or 3 small mesial and submesial spines (see Kemp, 1915: Fig. 23)); carpus of pereopod 1 with 2 dorsomesial and 1 distoventral spines in the new species (vs. 1 dorsomesial and 1 distoventral spines (Kemp, 1915: Fig. 22d)); merus with only 1 proximal ventral spine in the new species (see Fig. 5) (vs. 2–6 ventral spines (see Kemp, 1915: Fig. 22d)).
From W. annandalei, the new species is separated by 1) a non-articulated flagellum of exopod of maxilliped 3 (see Fig. 4 f) (vs. an articulated (see Sakai & Lheknim, 2014: 4 C)); 2) a well-developed long spines on carpus of pereopod 1 (cheliped) (Figs 5, 6) (vs. a feebly developed (see Sakai & Lheknim, 2014: 4 E)); 3) 2 a well-developed large distoventral spines on propodus of pereopod 1 (cheliped) in males (Figs 5, 6) (vs. 1 large and 1 smaller spines (Sakai & Lheknim, 2014: 4 D, E)); and 4) a well-marked proximal spine on ventral margin of merus of pereopod 1 (Figs 5, 6) (vs. merus unarmed (Sakai & Lheknim, 2014: 4 D, E)).
From W. nhatrangensis, the new species is separated by 1) the absence of dorsal tubercles on rostrum (see Fig. 2 a–c) (vs. present in W. nhatrangensis (see Ngoc-Ho et al., 2001: Fig. 1A, B)); 2) a longer rostrum, which is about 2.5 times as long as wide (see Fig. 2 c) (see Fig. 2) (vs. about as long as wide (Ngoc-Ho et al., 2001: Fig. 1B)); 3) the presence of 1 large spine arising ventromesially beside the fixed finger on distoventral margin of pereopod 1 (cheliped) in males (see Figs 5, 6) (vs. only fixed finger (Ngoc-Ho et al., 2001: Fig. 1D, E)); 4) the absence of a series of oblique crests on lower anterior half of propodus of pereopod 1 (cheliped) in males (see Figs 5, 6) (vs. with a series of well-marked oblique crests on lower anterior half of propodus of pereopod 1 (cheliped) (Ngoc-Ho et al., 2001: Fig. 1D, E)); 5) the presence of 1 distodorsal spine on propodus and 1 large mesial spine on carpus of pereopod 1 (cheliped) in females (see Figs 5, 6) (vs. absent (Ngoc-Ho et al., 2001: Fig. 1D, E)); and 6) telson is slightly longer than broad (see Fig. 2 g) (vs. broader than longer in W. nhatrangensis (Ngoc-Ho et al., 2001: Fig. 1C)).
description: Published as part of Kolevatov, Vasily & Marin, Ivan, 2022, Mud shrimps of the genus Wolffogebia Sakai, 1982 (Decapoda: Gebiidea Upogebiidae) with the description of a new species from the C ần Gi ớ Mangrove Biosphere Reserve, South Vietnam, pp. 51-72 in Zootaxa 5195 (1) on pages 53-62, DOI: 10.11646/zootaxa.5195.1.3, http://zenodo.org/record/7180559