Alpheus takla Anker 2023, sp. nov.
Creators: name: Anker, Arthur
Publisher: name: Zenodo
Year: 2023
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Malacostraca
Decapoda
Alpheidae
Alpheus
Alpheus takla

description: Alpheus takla sp. nov.
(Figs. 2F, G, 29–33, 34B–E, 35A, B, D, E, 52A)
(?) Alpheus microrhynchus.— Johnson 1965: 9 (part.) [not A. microrhynchus De Man, 1897].
Alpheus euphrosyne euphrosyne. — Banner & Banner 1982: 232 (part.?), fig. 73 (part., not fig. 73i); Chace 1988: 27 (part.?) [not A. euphrosyne De Man, 1897].
(?) Alpheus euphrosyne. — Banner & Banner 1966: 130 (part.?, not fig. 49); Wada 2013: 184, fig. 5 [not A. euphrosyne De Man, 1897].
(?) Alpheus sp. cf. audouini.— Johnson 1962: 53 (part.).
Alpheus macellarius. — Aaron-Cabrillos 2019: 22, fig. 3 [not A. macellarius Chace, 1988].
Alpheus sp. — Baobao et al. 2015: 337.
Type material. Holotype, male (cl 25.5 mm, tl ~70.0 mm, chl 41.0 mm), NMCR 99110, Philippines, Bohol, from fishermen, leg. Y. Cai, 18.12.2000. Paratypes: 4 males (cl 24.1–27.0 mm), 1 female (cl 24.6 mm), 1 ov. female (cl 27.2 mm), ZRC 2014.0668, same collection data as for holotype; 2 males (cl 23.9, 25.0 mm), OUMNH. ZC. 2019.06.66, same collection data as for holotype; 2 males (cl 23.3, 24.4 mm), FLMNH UF 68697, same collection data as for holotype; 3 males (cl 24.0–25.0 mm), 1 female (cl 27.6 mm), MNHN-IU-2022-2939, same collection data as for holotype.
Additional material. Philippines: 1 female (cl 22.0 mm), OUMNH. ZC. 2019.06.67, Cebu, Cebu City, fish market, leg. P.K.L. Ng et al., 14.12.2000; 2 males (cl 23.5, 25.7 mm), 1 female (cl 23.0 mm), OUMNH. ZC. 2019.06.68, unknown locality, fisheries import, leg. K. Nomura, 01.1998; 1 female (cl 26.4 mm), CBM 17105, same collection data as for previous specimens [YMP-1667h]; 1 female (cl 19.3 mm, missing both chelipeds), NMCR 99111, Mindanao, mangrove forest along coastal road between Dipolog and Dapitan, leg. J.C.Y. Lai & N.K. Ng, 29.01.2005; 1 male (cl 22.6 mm), USNM 252030, Luzon, Manila, market, no further data, 04.01.1908; 1 male (cl 23.5 mm), 2 females (cl 21.9, 25.4 mm), USNM 128409, Mactan, Calawisan, sta. 20578, leg. Santos, 28.05.1968.
Singapore: 1 male (cl 24.7 mm), 1 female (cl 26.7 mm), ZRC 1979.4.4.7–8, Jurong, prawn ponds, sta. B26, leg. S. R.F. R.S., 29.06.1954 [J7225–7226]; 1 female (cl 21.7 mm, missing major cheliped), ZRC 1979.4.4.9, Jurong, prawn ponds, sta. B26, leg. S. R.F. R.S., 29.06.1954 [J7994]; 1 male (cl 20.7 mm), 4 females (cl 19.8–29.7 mm), ZRC 1979.4.4.1–5, Jurong, prawn ponds, sta. B17, leg. S. R.F. R.S., 1– 2.06.1954; 1 female (cl 15.9 mm) + 1 major cheliped, ZRC 2014.0680, Jurong prawn pond, no further data [J8049]; 1 male (cl 21.5 mm), 1 female (15.8 mm), ZRC 2014.0673, Singapore, no further data [ex cat. nr. 530, Nanyang University Department of Biology, det. “ Callianassidae, Alpheus bisincisus ”]; 1 male (cl 26.4 mm), NHM 1975.457.1, unknown locality, leg. Singapore Fisheries Research Station (det. A.H. Banner as A. euphrosyne).
Thailand: 1 ov. female (cl 32.5 mm, tl 86.0 mm, chl 52.0 mm), ZRC 1999.0850, Thailand, Ranong, 08.09.1929.
Indonesia: 1 male (cl 21.0 mm), OUMNH. ZC. 2019.06.69, Papua, Ajkwa Island, mangrove, leg. A. Darmawan et al., 20.07.2012; 1 female (cl 17.3 mm), MNHN-IU-2018-5596, Papua, Kamora, mangrove, leg. A. Darmawan et al., 07.08.2012; 1 female (cl indet., tl 85.0 mm), ZMA Crust.De. 202792, Sulawesi, Makassar, Siboga-Expedition sta. 71, mud, sand with mud, coral, depth: to 32 m (?), 10.05.1899 – 07.06.1899.
Papua New Guinea: 1 male (cl 15.7 mm), USNM 1172134, Madang Harbour, Naui Island, mangrove, poison station BBC1492, depth: 0–1 m, leg. B. Collette, 28.05.1970.
Australia: 1 male (cl 24.8 mm), 2 females (cl 27.2, 29.0 mm), NTM Cr. 002639, Queensland, Gladstone, Calliope River, sta. 151, leg. P. Saenger, 1982; 1 female (cl 31.0 mm), NTM Cr. 000865, Queensland, Townsville, mangrove swamp, don. P. Sammarco, 15.02.1984; 1 male (cl 27.4 mm, missing major cheliped), AM P 28129, Queensland, Mangrove Creek south of Ross River, 19°22’S 146°44E, leg. B. Campbell, 03.1962.
Tentative identification. Alpheus cf. takla sp. nov. Indonesia: 1 female (cl indet., tl 61.0 mm), ZMA Crust. De. 202791, eastern Java, Siboga-Expedition sta. 4, eastern Java, anchorage off Jangkar (= Djangkar), 7°42’S, 114°12.6’E, shore, 09.03.1899.
Description. See Figs. 2F, G, 29–31. Very large species of Alpheus (maximal cl 32.5 mm, tl 86.0 mm in present material, but see below). Carapace glabrous, without pubescence, with slight grooves. Rostrum short, subtriangular, distally acute, not reaching 0.3 length of first article of antennular peduncle; rostral carina present as faint elevation extending at most to eye level; rostro-orbital furrows poorly demarcated. Pterygostomial angle broadly rounded; cardiac notch deep.
Pleon smooth, without pubescence. Telson very broad, subrectangular, very slightly tapering towards posterior margin, about 1.7 times as long as maximal width near proximal margin; lateral margins almost straight; dorsal surface with shallow longitudinal median depression (sometimes barely distinct or absent) and two pairs of short spiniform setae inserted in deep pits at some distance from lateral margins, first pair near telson mid-length, second pair between 0.7 and 0.8 of telson length; posterior margin rounded, with two pairs of small spiniform setae at posterolateral angles, lateral shorter than mesial.
Antennular peduncle with stylocerite broad, markedly convex laterally, with acute tip, latter slightly overreaching distal margin of first article; ventromesial carina with low, blunt tooth; second article about 2.1–2.2 times as long as wide. Antennal peduncle with basicerite armed with stout, sharp tooth; carpocerite reaching distinctly beyond scaphocerite; scaphocerite with lateral margin nearly straight to slightly convex; blade very broad, separated from broad distolateral tooth by deep cleft; anterior margin of blade broadly rounded, greatly exceeding tip of distolateral tooth.
Third maxilliped with antepenultimate article not particularly broadened; penultimate article elongate, about 3.5 times as long as wide, slightly widening distally, with some elongate setae on ventral margin; ultimate article with dense transverse rows of short serrulate setae on mesial surface and longer setae on dorsal and lateral surfaces, especially near or on apex; coxal lateral plate bluntly protruding dorsally; exopod overreaching end of antepenultimate article.
Major cheliped of A. edwardsii - type. Merus stout, about twice as long as wide; ventromesial margin unarmed distally. Carpus very short, cup-shaped. Chela large, massive, with fingers about 0.6 length of palm. Mesial face of palm largely smooth, with slight mesial transverse ridge (or rather elevation) in proximal half, running obliquely from central area towards ventral surface of palm. Lateral face of palm smooth; lateral longitudinal groove deep, subrectangular; proximal half without clear transverse ridge. Dorsal shoulder smooth, gently sloping into broad transverse groove with angle of about 45°. Ventral shoulder pronounced, not protruding in lateral view, broadly rounded, smooth. Pollex with mesial face usually finely granulated, especially near distomesial angle, with well-developed subdistal mesial ridge near margin, marked by proximal protuberance; area ventral to mesial subdistal ridge deeply depressed; distomesial angle distinctly about 90°, blunt; lateral face smooth; distolateral angle superior to 90°. Dactylus with short, dorsally protruding dorsal ridge; mesial surface with barely detectable granulation; lateral surface smooth; dactylar plunger very stout, large, with anterior margin well delineated, separated from ventral margin of dactylus; distal surface of plunger rounded anteriorly, remaining area obliquely truncate.Adhesive discs small.
Male minor cheliped with chela strongly balaeniceps. Merus distinctly slenderer than that of major cheliped, about 2.5 times as long as wide; ventral margin with distomesial angle unarmed. Chela feebly swollen, slender in lateral view, with fingers about as long as palm. Palm subcylindrical, compressed, feebly swollen; all surfaces smooth, without granulation; both mesial and lateral longitudinal grooves well marked; dorsal shoulder and transverse groove poorly marked, former present only in form of slight, gently sloping elevation; ventral transverse groove poorly developed, marked by smooth ventral shoulder on lateral surface. Pollex with mesial surface bearing row of balaeniceps setae on low crest extending from base to mid-length of pollex or beyond it; lateral surface with similar row of balaeniceps setae as on mesial surface. Dactylus with conspicuous lateral expansion (balaeniceps expansion) in proximal half, about 1.7 as long as maximal width; lateral and mesial dactylar ridges each with dense rows of balaeniceps setae. Cutting edges of both fingers shallowly excavated on each side of sharp, blade-like ridge.
Female minor cheliped simple, not balaeniceps. Chela slender, not particularly swollen, with fingers slightly longer than palm. Palm with surface smooth, not granulated; mesial longitudinal groove not distinct; lateral longitudinal groove feebly developed, very shallow; dorsal and ventral transverse groove and shoulders not distinct, ventral shoulder indicated by very faint sinus laterally. Fingers simple, with sharp cutting edges, slightly gaping when closed; dactylus with low longitudinal ridge laterally; fingertips strongly curved and crossing.
Second pereiopod with ratio of carpal subarticles approximately equal to 4.3: 2: 1: 1: 1.5. Third pereiopod moderately robust; ischium unarmed or armed with very small spiniform seta on ventrolateral surface; merus about four times as long as maximal width, unarmed; propodus with six or so stout spiniform setae on ventral margin and at least one stout spiniform seta on distoventral margin adjacent to dactylus; dactylus about 0.4 length of propodus, spatulate, expanded, wider than propodus in dorsal view, with two rows of setae (or tufts of setae) along ridges. Fourth pereiopod generally similar to third pereiopod, shorter and slenderer. Fifth pereiopod much slenderer than third and fourth pereiopods; ischium usually unarmed; propodus with three small spiniform setae on ventral margin and one spiniform seta close to dactylus, and well-developed setal brush, latter extending to proximal half of propodus; dactylus subspatulate, less expanded compared to that of third or fourth pereiopod, about 0.35 length of propodus.
Male second pleopod with appendix masculina almost as long as appendix interna. Uropod with each protopodal lobe ending in subacute tooth distally; exopod and endopod broad, ovate; diaeresis of exopod complete, broadly concave towards posterior end, with broadly subtriangular lobe near small distolateral spiniform seta and adjacent distolateral tooth; lateral margin of exopod broadly convex.
Eggs numerous (> 100 in larger females), small; egg diameter about 0.6 mm.
Colour pattern. Body (carapace and pleon) ranging from uniform olive-brown to greenish blue, without transverse bands; orbital hoods conspicuously whitish translucent, contrasting with dark frontal area of carapace; antennules and antennae uniform brown to blue-green; flagella pale brownish to greenish; mesial face of major chela largely dark olive-brown or olive-green; lateral face of major chela palm whitish with blue markings, especially bright along lateral longitudinal depression, and with olive-brown area dorsally and orange area distally; distolateral portion of pollex orange; lateral face of dactylus orange with some olive tinge; distal portion of both fingers greypurplish; plunger bright red-orange; minor chela olive-brown or brown-green; second to fifth pereiopods reddish or reddish green; pleopods greenish; telson and uropods dark uniform olive-brown to greenish blue; uropodal exopod with dusky or dark blue area posterior to transverse suture (Figs. 32, 33, 35A).
Type locality. Bohol, Philippines (collection locality of the holotype and several paratypes).
Distribution. Tropical Indo-West Pacific from Thailand to northern Australia (Fig. 52A); specific localities include the Philippines (e.g., Bohol, Panglao, Cebu, Luzon, Mindanao, Mactan), Singapore (Jurong), Thailand (Ranong), Indonesia (Sulawesi, Papua, record of A. cf. takla sp. nov. from Java), Papua New Guinea (Madang), Australia (Northern Territory, Queensland).
Etymology. The specific epithet refers to “takla”—the local Tagalog name of this large and conspicuous snapping shrimp harvested for food in rural areas of Bohol, the type locality of the new species. Used as a noun in apposition.
Common names proposed. Takla; giant snapping shrimp.
Ecology and biology. Alpheus takla sp. nov. lives in spacious, deep burrows built in very soft, soggy mud among mangrove roots (Fig. 35B–F). Each burrow is typically occupied by a male-female pair. The species appears to be adapted to marine to slightly brackish conditions, which are typical for mangrove forests and creeks. The large number of eggs and their small diameter suggest an extended larval development in A. takla sp. nov.
Alpheus takla sp. nov. appears to be the largest snapping shrimp in the world, with most specimens examined in this study exceeding 60 mm tl and largest individuals reaching almost 90 mm tl (Figs. 32H, 33). In the largest specimens, the impressive major chela typically exceeds 45 mm in length (palm + fingers) and in one ovigerous female from Thail and (86 mm tl, ZRC 2014.0723), its length reaches 52 mm. The species also has an unusually large, stout, strongly calcified ocellar beak (bec ocellaire), protruding between the eyestalks.
Using quadrat sampling in the mangroves of Bohol, Philippines, Baobao et al. (2015) determined the mean density of A. takla sp. nov. (as Alpheus sp.) at seven individuals per m 2; the body weight of the shrimps ranged from 3.87 g to 12.86 g; and the total length from 47.8 mm to 74.4 mm (although, as noted above, the maximal total length of the species is closer to 90 mm). In dense mangroves of northern Queensland, Australia, the burrows of A. takla sp. nov. and A. malabaricus (sensu lato, see below) are sometimes inhabited by small gobies (Fig. 35E).
In Bohol, Panglao and probably some other parts of the Philippines, A. takla sp. nov. is known as “takla” (see etymology) and is harvested for consumption by local fishermen or “gatherers” (Baobao et al. 2015; Aaron-Cabrillos 2019, misidentified as A. macellarius Chace, 1988; see also Fig. 32). Many gatherers use small crabs known in Bohol as “asan” [Parasesarma cf. eumolpe (De Man, 1895), Sesarmidae] as bait to lure the taklas from their burrows (M. Gabe, pers. comm.). The usual technique is to remove all crab’s appendages, tie it to an abaca (Musa textilis Née) fiber, drop the bait on the fiber into the takla’s burrow (filled with water), wait until the shrimp comes up and grasps the bait and then pull quickly and with force and try to secure the shrimp with the hands. Trying to defend itself, the takla may deliver a powerful and painful snap. The harvested taklas are then cooked in Sinigang broth with vegetables or in coconut cream sauce (Fig. 32C–E); see also links to two videos showing the takla harvest and preparation in Calape, Bohol, at the end of the reference section). According to Aaron-Cabrillos (2019), the bait used for collecting taklas in Clarin, Bohol, is a “hermit crab”. In 2014, the average daily catch per gatherer in Bohol was 75 shrimps, which is significantly lower compared to the average catch in the 1980–1990s, ranging from 150 to 300 shrimps per day (Baobao et al. 2015). The possible causes of the population decline of A. takla sp. nov. in Bohol identified by Baobao et al. (2015) are the unregulated gathering of snapping shrimps and general loss of mangrove swamps due to fishpond conversion and commercial firewood production. It is possible that the ecologically and morphologically very similar A. eurydactylus is also harvested for food in the Philippines, together with A. takla sp. nov.
Taxonomic remarks. The Singaporean material reported as A. microrhynchus by Johnson (1962, 1965) contained at least two species: the larger specimens (tl> 60 mm) were reidentified as A. takla sp. nov., whereas the smaller ones were A. eurydactylus. At least some of the previous records of A. euphrosyne or A. euphrosyne euphrosyne (e.g., Banner & Banner 1966, 1982; Chace 1988) may be referable to A. takla sp. nov. For instance, the illustrations of a 78 mm male of A. euphrosyne euphrosyne from Australia in Banner & Banner (1982: fig. 73, except 73i) probably represents A. takla sp. nov., although the entire Australian material examined by these authors may also contain A. eurydactylus and possibly other species. Therefore, three large specimens from Gladstone (Queensland, Australia, NTM Cr-002639) identified by A.H. Banner & D.M. Banner as A. euphrosyne euphrosyne were reexamined by the present author and confirmed as A. takla sp. nov. (see also Fig. 35A).
The two females from Jangkar, Java, and Makassar, Indonesia, reported by De Man (1911) under A.microrhynchus (deposited in RMNH under ZMA.Crus.D.202791 and ZMA Crus.D.202792, respectively), were photographed and briefly examined at the author’s request by Charles H.J.M. Fransen (RMNH). The smaller female from Jangkar (ZMA.Crus.D.202791) is generally similar to A. takla sp. nov., but differs from it mainly by the unarmed antennal basicerite, as noted by De Man (1911), and the presence of a distinct mesial transverse ridge on the major chela palm, similar to that of A. cyanoteles and A. paludicola (Yeo & Ng 1996). In addition, in this specimen, the dorsal surface of the telson is smooth, without a trace of median depression; the mesial surface of the major chela, including the distomesial angle of the pollex, presents no granulation; and the rostrum is longer than the rostrum of the syntype of A. microrhynchus (Fig. 2A) and more similar to that of A. takla sp. nov. (Fig. 30A). The proportions of the carpal subarticles of the second pereiopod and the broadened spatulate dactylus of the third and fourth pereiopods do not allow to identify this specimen as A. microrhynchus sensu De Man (1897), whereas the absence of granulation on the major chela excludes it from A. eurydactylus. Therefore, it is here tentatively assigned to A. cf. takla sp. nov., awaiting collection of fresh specimens throughout central Indonesia, especially males.
On the other hand, the larger female from Makassar (ZMA Crus.D.202792) can be more reliably assigned to A. takla sp. nov., based on the well-developed rostrum (with a blunt carina); the shallow but distinct adrostral furrows; the presence of a sharp tooth on the antennal basicerite; the general shape of the telson, including the presence of a very shallow median depression on the dorsal surface (although barely distinct, and present only in some specimens of A. takla sp. nov.) and relative position of the dorsal spiniform setae; the generally smooth surfaces of the major and minor chela (except for some fine granulation on the mesial face of the pollex); the dorsal shoulder of the major chela gently sloping into the transverse groove; the proportions of the carpal subarticles of the second pereiopod; the spatulate dactyli of the third to fifth pereiopods; and finally, the very large size of the specimen (tl 85.0 mm). The very vague collection data for the Makassar specimen (mud, sand, corals, up to 32 m) does not exclude the possibility that it could have been collected on mud bottoms in a mangrove area (sampling at the Siboga Expedition station 71 lasted almost for one month, cf. De Man 1911: 413).
Considering all characters combined, including the colour pattern, A. takla sp. nov. appears to be closest to A. eurydactylus, A. microrhynchus and A. cyanoteles. In A. takla sp. nov., most of the surface of the major chela and the entire surface of the minor chela are perfectly smooth, with a small field of small and rather inconspicuous granules present only near the distomesial angle of the pollex (Fig. 31B). In contrast, the granulation is very conspicuous on the chelae of A. eurydactylus, especially on the distomesial surface of the major chela (Fig. 15C). All specimens of A. takla sp. nov. have a small, sharp tooth on the antennal basicerite (Fig. 30D), which is unarmed in A. eurydactylus (Fig. 14D). In addition, the plunger of the major chela is bright orange-red in A. takla sp. nov. (Figs. 32A, F, 34A) vs. whitish with a bluish base and orange distally in A. eurydactylus (Fig. 16C). The other two species, i.e., A. microrhynchus and A. cyanoteles, can be separated from A. takla sp. nov. by the less expanded, sub-balaeniceps to almost conical dactyli of the walking legs; the distinctly shorter rostrum (A. microrhynchus); the more angular orbital hoods (A. cyanoteles); the ovigerous females carrying a small number of very large eggs (which are more numerous and much smaller in the new species, see above); and several features of the colour pattern (cf. Figs. 21, 22, 24, 32, 33, 35A). The uniform colour pattern with a bright orange dactylar plunger of the major chela is present in both A. microrhynchus and A. takla sp. nov.; however, in A. microrhynchus, the posterior third of the uropodal exopod is marked by a much brighter blue area (cf. Fig. 21C, 22E, 32B, 33, 35A; see also Table 1).
The remaining of the above-treated species of the A. euphrosyne — A. microrhynchus complex, viz. A. euphrosyne, A. richardsoni and A. nomurai sp. nov., differ from A. takla sp. nov. by a greater number of morphological characters (see Table 1) and very different colour patterns (cf. Figs. 8, 9, 17, 18, 28, 32, 33, 35A), and are therefore more distantly related to the new species.
description: Published as part of Anker, Arthur, 2023, Revision of Alpheus euphrosyne De Man, 1897 and A. microrhynchus De Man, 1897, with description of three new species and taxonomic remarks on several other morphologically and ecologically similar snapping shrimps (Malacostraca: Decapoda: Alpheidae), pp. 1-115 in Zootaxa 5282 (1) on pages 57-67, DOI: 10.11646/zootaxa.5282.1.1, http://zenodo.org/record/7912292