Alpheus djeddensis Coutière, 1897

Anker, Arthur, 2024, Preliminary revision of Alpheus djeddensis Coutière, 1897 species complex, with description of three new species of goby-associated snapping shrimps and taxonomic notes on A. macellarius Chace, 1988 and A. djiboutensis De Man, 1909 (Decapoda: Alpheidae), Zootaxa 5472 (1), pp. 1-63 : 7-19

publication ID	https://doi.org/ 10.11646/zootaxa.5472.1.1
publication LSID	lsid:zoobank.org:pub:7FA16A7A-7AE7-4081-941B-F797F92F513A
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scientific name	Alpheus djeddensis Coutière, 1897
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Alpheus djeddensis Coutière, 1897 View in CoL

Figs. 1A–C View FIGURE 1 , 2–10 View FIGURE 2 View FIGURE 3 View FIGURE 4 View FIGURE 5 View FIGURE 6 View FIGURE 7 View FIGURE 8 View FIGURE 9 View FIGURE 10

Alpheus djeddensis Coutière 1897: 202 View in CoL ; De Man, 1909: 160, pl. 8, figs. 25, 26; Fransen et al. 1997: 35 (type material); Banner

& Banner 1981: 17, fig. 1c–j (part.?). Alpheus Djeddensis. View in CoL — Coutière 1899: 54, 232 (varieté Djeddensis View in CoL ), figs. 285, 313. (?) Alpheus brevirostris View in CoL . — Ortmann 1890: 479 [not A. brevirostris ( Olivier, 1811) View in CoL , fide De Man (1909): 160, foot note]. Alpheus rapax View in CoL . — Debelius 2001: 151, colour photograph [not A. rapax Fabricius, 1798 View in CoL ]. Not Alpheus djeddensis. View in CoL — Vine 1986: 104, colour photograph [= A. karplusi Anker, 2022 ]; Debelius 1998: 273, colour photograph; Minemizu 2000: 84, colour photograph; Debelius 2001: 150; Thompson 2004: 106, fig. 1; Burns et al. 2019:

275 [all = A. berumeni sp. nov.]; Dehghani et al. 2019: 483, fig. 2C, D [= A. tigrinus sp. nov.]. Not Alpheus djeddensis sensu lato. — Anker & De Grave 2016: 350, fig. 8A, B [= A. cf. tigrinus sp. nov.; see text]. (?) Not Alpheus djeddensis. — Johnson 1976: 37; Banner & Banner 1983: 28; Banner & Banner 1984: 38; Miya 1984: 92;

Hayashi 1998: 214; Simões et al. 2001: 83 [identity cannot be confirmed without examination of material].

Type material. Lectotype: 1 female (cl 20.5 mm), RMNH. CRUS.D.1781, Saudi Arabia, Jeddah (spelled Djeddah), leg. J.A. Kruyt, 1880 . Paralectotypes: 1 male, 2 females (cl indet.), RMNH. CRUS.D.1781, same collection data as for lectotype (examined by C.H.J.M. Fransen) ; 1 male (cl 18.9 mm), MNHN-IU-2016-9011, same collection data as for lectotype .

Other material examined. 1 male (cl 19.3 mm), FLMNH UF 36913 , Red Sea , Saudi Arabia, Farasan Islands , Zahrat Durakah (Zahirah), 16°50’09.2”N / 42°18’22.7”E, fringing reef / slope, depth 2–6 m, possibly with Cryptocentrus caeruleopunctatus , leg. M.L. Berumen (A. Anker et al.), 11.03.2013 (BDJRS-2466) GoogleMaps ; 1 female (cl 11.3 mm, with bopyrid isopod, latter not detached), FLMNH UF 71917 , Red Sea , Saudi Arabia, Thuwal, KAUST, near King Abdullah Monument, 22°20’26.2”N / 39°05’15.1”E, sandflat with rubble and sparse seagrass, depth 1 m, suction pump, in burrow, leg. A. Anker et al., 10.01.23 (AA-22-462) GoogleMaps ; 1 male, 1 female (cl indet.), RSRC (specimens presently kept alive in aquarium), Red Sea , Saudi Arabia, Thuwal, KAUST, near King Abdullah Monument, 22°20’32.2”N / 39°05’03.1”E, sandflat with rubble and sparse seagrass near channel, depth 0.5–1 m, suction pump, in burrow, leg. V.N. Peinemann, 30.09.22 (AA-22-256); 1 major cheliped (20.0 mm) and 1 ambulatory pereiopod, RSRC, Red Sea, Saudi Arabia, Thuwal, KAUST, near Island Recreation Center, 22°18’52.6”N / 39°05’24.5”E, sandflat with sparse rubble, depth 0.5 m, suction pump, in burrow, leg. A. Anker, 09.12.22 (AA-22-378) GoogleMaps .

Redescription. Carapace conspicuously pitted, except along mid-dorsal line, and evenly covered with short setae ( Figs. 1B View FIGURE 1 , 3A View FIGURE 3 ). Rostrum well developed, moderately slender, about 1.5–1.7 times as long as wide at base, straight, subacute distally, not reaching distal margin of first article of antennular peduncle; rostral carina well demarcated, blunt, rising above orbital hoods, gently sloping into shallow adrostral furrows, continuing well beyond base of orbital hoods, only slightly widening posteriorly, fading well posterior to base of orbital hoods, not reaching mid-length of carapace ( Figs. 1B View FIGURE 1 , 2B View FIGURE 2 , 3A, B View FIGURE 3 , 4A, B View FIGURE 4 ). Rostro-orbital region moderately produced anteriorly ( Figs. 3A, B View FIGURE 3 , 4A, B View FIGURE 4 ). Orbital hoods swollen, slightly projecting anteriorly in lateral view, unarmed; frontal margin between rostrum and orbital hood shallowly concave ( Figs. 2B View FIGURE 2 , 3A, B View FIGURE 3 , 4A, B View FIGURE 4 ). Pterygostomial angle rounded; cardiac notch deep ( Figs. 2A View FIGURE 2 , 3B View FIGURE 3 , 4B View FIGURE 4 ).

Telson very broad, subrectangular, gently tapering distally, about 1.8 times as long as maximal width, with lateral margins slightly convex at about 0.7 of telson length, gently tapering in posterior third; dorsal surface faintly pitted, with two pairs of stout short spiniform setae both inserted at considerable distance from lateral margin, first pair near telson mid-length, second pair at about 0.7 of telson length; mid-dorsal groove usually discernible, but shallow; posterior margin broadly rounded, with row of slender spiniform setae above plumose setae; posterolateral angles each with one pair of spiniform setae, mesial ones stouter and almost three times as long as lateral ones ( Figs. 2I View FIGURE 2 , 3C View FIGURE 3 , 4C View FIGURE 4 ).

Eyes with large, well-pigmented cornea ( Figs. 3A View FIGURE 3 , 4A View FIGURE 4 ).Antennular peduncle moderately long and stout; stylocerite swollen laterally, ending in sharp point, latter falling short of distal margin of first article; ventromesial carina with broad, subtriangular tooth with anteroventrally directed, subacute tip; second article 2.2–2.3 times as long as wide; lateral antennular flagellum with secondary ramus fused to main ramus over most of its length, with numerous groups of aesthetascs distally, starting from 15th or so subdivision ( Figs. 2B View FIGURE 2 , 3A, B View FIGURE 3 , 4A, B, D View FIGURE 4 ). Antenna with basicerite moderately stout, armed with sharp tooth on distoventral margin; scaphocerite with lateral margin broadly shallowly concave; blade moderately wide, rounded, slightly or more significantly exceeded by stout, subacute distolateral tooth; scaphocerite slightly overreaching end of antennular peduncle and subequal in length to carpocerite ( Figs. 2B View FIGURE 2 , 3A, B, D View FIGURE 3 , 4A, B View FIGURE 4 ).

Mouthparts not dissected, typical for genus in external observation. Third maxilliped moderately stout; coxa with subacutely projecting lateral plate; antepenultimate article flattened on ventrolateral surface, with smooth longitudinal ridge running parallel to dorsal margin on lateral surface and strongly crenulate ventromesial margin, about six times as long as high; penultimate article 1.8 times as long as wide distally, not bulging ventrally, distoventral margin with tuft of moderately long setae, latter barely reaching half-length of ultimate article, dorsal margin with long setae; ultimate article covered with rows of elongate setae, dorsal and apical ones longest; arthrobranch large ( Figs. 3E View FIGURE 3 , 4E, F View FIGURE 4 ).

Major cheliped robust; ischium stout, smooth; merus moderately stout, trigonal in cross-section, about 2.6–2.8 times as long as maximal width, distodorsal margin ending bluntly, ventrolateral margin slightly crenulated distally, ventromesial margin somewhat rugose, armed with two or three short spiniform setae inserted on low bumps, without distal tooth; carpus short, wide, cup-shaped, with groove on mesial surface; chela somewhat elongate, with rows of long setae along dorsal and ventral margins; palm compressed, subrectangular in cross-section, length / maximum height ratio around 2.0; mesial surface faintly granulated; dorsal margin flattened, with very low, smooth, longitudinal ridges fringed with long setae, and well-marked transverse groove subdistally, slightly extending to mesial and lateral surfaces; ventral margin feebly concave; fingers somewhat unequal in length, with dactylus slightly longer than pollex and about 0.6–0.7 length of palm, not twisted or significantly deviating from chela axis; dactylus distally rounded, with plunger in form of broad bulge, more or less well demarcated from anterior cutting edge; adhesive disks small ( Figs. 2C–E View FIGURE 2 , 3F–H View FIGURE 3 , 5A, B View FIGURE 5 ).

Minor cheliped relatively robust; ischium short, smooth; merus not noticeably more slender than that of major cheliped,trigonal in cross-section,about2.8–2.9times as long as maximum width,distodorsal angle blunt,ventrolateral margin faintly crenulated, ventromesial margin slightly rugose, armed with few short spiniform setae, without distal tooth; carpus longer than that of major chela, distally widening, cup-shaped; chela not particularly elongate or swollen, slender, fringed with long setae along dorsal and ventral margins; palm compressed, subrectangular-oval in cross-section, length / maximum height ratio about 2.0 in both sexes; mesial surface slightly granulated; dorsal margin without transverse groove; ventral margin straight or with faint sinus distally; fingers subequal in length, about 1.2 times longer than palm, somewhat gaping when closed, with rows of densely grouped, thick, balaenicepstype setae on each side of dactylus and pollex, in both sexes; adhesive disks reduced ( Figs. 2F–H View FIGURE 2 , 3I–K View FIGURE 3 , 5C–E View FIGURE 5 ).

Second pereiopod moderately slender; ischium and merus subequal in length; carpus with five subarticles, first much longer than second, ratio of carpal subarticles approximately equal to 3.0/2.5/1.0/1.0/1.5; chela slightly longer than distal-most carpal subarticle ( Figs. 3L View FIGURE 3 , 4G View FIGURE 4 ). Third pereiopod moderately slender; ischium with stout spiniform seta on ventrolateral surface; merus almost five times as long as maximal width, ventromesial margin unarmed distally; carpus slightly more than half-length of merus, much more slender than merus, unarmed; propodus slightly longer than carpus, with five stout spiniform setae along ventral margin and one distal pair of longer spiniform setae near base of dactylus; dactylus about 0.45 length of propodus, gradually curving distally, spatulate, with longitudinal keel fringed by several tufts of setae ( Figs. 2G–I View FIGURE 2 , 3M–O View FIGURE 3 , 4H–J View FIGURE 4 ). Fourth pereiopod generally similar to third pereiopod, somewhat more slender; propodus occasionally with more (up to seven) spiniform setae along ventral margin, in addition to distal pair of spiniform setae near base of dactytus ( Fig. 3P, Q View FIGURE 3 ). Fifth pereiopod much more slender than third and fourth pereiopods; ischium with spiniform seta on ventrolateral surface; merus somewhat curved, at least six times as long as wide; carpus more slender than merus, about 0.8 length of merus; propodus subequal to carpus in length, with well-developed cleaning brush on distal half of ventrolateral surface composed of dozen or so of transverse rows of microserrulate setae, and eight stout spiniform setae along ventromesial margin, including distal spiniform seta adjacent to base of dactylus; dactylus subspatulate, only slightly broadened ( Fig. 4K, L View FIGURE 4 ).

Male second pleopod with appendix masculina about 0.9 length of appendix interna, densely covered with long stiff setae ( Fig. 4M View FIGURE 4 ). Uropod without specific features; mesial and lateral lobes of protopod each ending in sharp distal tooth; exopod and endopod broad, oval; diaeresis straight for most part, except for blunt lobe adjacent to small but stout spiniform seta; endopod narrower than exopod, with row of small spiniform setae above plumose setae on distal margin ( Fig. 8B View FIGURE 8 ).

Colour pattern. Somewhat variable ( Figs. 6–10 View FIGURE 6 View FIGURE 7 View FIGURE 8 View FIGURE 9 View FIGURE 10 ). Background colour ranging from pale bluish to pale yellow or pale greenish. Carapace with several transverse (dorsally) and more oblique (laterally), greenish brown or greenish blue bands composed of red chromatophores on blue or bluish brown background; most bands with irregular edges and smaller pale patches within; anterolateral bands on each side of orbital hoods darker; post-rostral area typically with small white patch or streak between eyes. Pleon with conspicuous transverse banding consisting of one complete posterior band running across each pleonite and one incomplete anterior band occupying only anterodorsal section of each pleonite; band on fifth somite not closing, i.e., not forming ring; saddle on first pleonite more or less conspicuous, whitish or yellow. Bands on carapace and pleon more diffuse, in form of patchy network, in very large individuals ( Fig. 6 View FIGURE 6 ). Telson with green-brown or blue-brown patches on pale bluish or yellowish background on proximal half, mostly blue distally, typically with transverse, whitish or yellowish stripe. Antennular peduncles pale bluish or yellow with large bluish or brownish areas speckled with red chromatophores; stylocerite largely blue, except for whitish yellow tip and proximal quarter (area above statocyst) ( Figs. 6A View FIGURE 6 , 8A View FIGURE 8 , 9B View FIGURE 9 ); antennal carpocerite and scaphocerite largely blue with red chromatophores and some pale or yellowish areas; antennular and antennal flagella deep blue ( Figs. 6 View FIGURE 6 , 7 View FIGURE 7 , 8A View FIGURE 8 , 9A, B View FIGURE 9 , 10 View FIGURE 10 ). Chelipeds with pale blue or yellowish background and with variously shaped and sized patches of bluish brown or greenish brown, occupying parts of merus, most of carpus and large areas on mesial face of palm of chela; patches on chela large, irregular, and mostly interconnecting; pollex and dactylus greenish blue proximally, calcified distal portion pink or orange; lateral face of chelae with similar patches as on mesial face, however, with less vivid colours. Second to fifth pereiopods largely blue with red chromatophores and bright reddish pink or orange pink articulations. Uropods dominated by blue colour, with some brownish-greenish and yellow areas.

Common names. Jeddah goby shrimp; Red Sea goby shrimp.

Type locality. Jeddah , Saudi Arabia .

Distribution. Western Indian Ocean: presently known only from the Red Sea, with confirmed records from Saudi Arabia and photographic records from Egypt; a record from Eritrea ( Ortmann 1890; De Man 1909) needs verification. The species is most likely present in suitable habitats across the entire Red Sea.

Ecology. Most abundant on near-shore sandflats with silty or muddy component, often close to reef channels or mangroves, from the intertidal to about 10 m; often associated with the gobies Cryptocentrus caeruleopunctatus (Rüppell) and possibly C. cryptocentrus (Valenciennes) ( Figs. 10 View FIGURE 10 , 38A View FIGURE 38 ; Karplus et al. 1972a, 1972b; Ryanskiy 2022; see also below).

Remarks. De Man (1909) was able to compare side by side his two type specimens of A. djiboutensis with Coutière’s type series of A. djeddensis and used several characters to distinguish these two species. He noted that in both species, the carapace has a short pubescence and is conspicuously pitted, except for the mid-dorsal area. The main distinguishing features between A. djeddensis and A. djiboutensis according to De Man (1909) are: (1) rostro-orbital region slightly protruding beyond anterolateral margin of the carapace in A. djeddensis vs. more strongly protruding in A. djiboutensis ( Fig. 1B, D View FIGURE 1 ); (2) antennal scaphocerite with blade much broader and being only very slightly exceeded by the distolateral tooth in A. djeddensis vs. with blade relatively narrower and being distinctly exceeded by the distolateral tooth in A. djiboutensis ( Fig. 1B, C–E View FIGURE 1 ); (3) major cheliped relatively more slender, with merus and chela each about 3.0 times as long as wide/high in A. djeddensis vs. 2.5 times as long as wide/high in A. djiboutensis ( Fig. 1G View FIGURE 1 ); (4) minor chela similarly more slender in A. djeddensis compared to that of A. djiboutensis ( Fig. 1A, H View FIGURE 1 ); (5) distomesial margin of the major and minor cheliped meri ending in blunt tooth in A. djeddensis [“dent obtuse” in Coutière (1897)] vs. ending in a sharp tooth in A. djiboutensis [“dent aiguë beaucoup plus large” for the major cheliped and “dent aiguë” for the minor cheliped, although neither of these teeth was clearly illustrated by De Man (1909)]. Neither Coutière (1897) nor De Man (1909) described in detail the second to fifth pereiopods of A. djeddensis , although the latter author stated that the ambulatory pereiopods of A. djiboutensis are very similar to those of A. djeddensis . Furthermore, it can be added that the telson of the larger type specimen of A. djiboutensis ( Fig. 1F View FIGURE 1 ) is noticeably narrower than in A. djeddensis ( Figs. 2I View FIGURE 2 , 3C View FIGURE 3 , 4C View FIGURE 4 , 8B View FIGURE 8 ).

De Man’s (1909) relatively detailed account and the accompanying illustrations of A. djiboutensis ( Fig. 1C–K View FIGURE 1 ) provide sufficient evidence to treat A. djiboutensis as a species distinct from A. djeddensis . In particular, the more protruding orbito-rostral region and the distomesially armed meri of the chelipeds are considered as two most important characters that are not or to a lesser degree affected by age, sexual dimorphism and frequent regenerations, the latter being especially problematic while comparing the relative proportions of the chelipeds.Among the Red Sea material examined in this study, only three specimens agree reasonably well with the De Man’s (1909) description of A. djiboutensis (see below). In all other specimens from the Red Sea available for this study (including those assigned to the below-described new species), the orbito-rostral region is moderately protruding and the cheliped meri have at most a blunt tooth or protuberance at the distomesial end, not a sharp tooth as descried by De Man (1909).

Coutière’s (1897) original type series of A. djeddensis contained, according to the author, three males and two females. However , the RMNH type series contains only the female lectotype ( Fig. 2 View FIGURE 2 ) , and three paralectotypes, one male and two females (all part of the lot RMNH Crus. D.1781). A large male of A. djeddensis collected in Jeddah by J.A. Kruyt and examined by the present author more than 20 years ago ( Anker 2001, under MNHN Na 2358) was found again in 2019 and reexamined. The label accompanying this specimen (now MNHN-IU-2016-9011) leaves no doubt that this is the fifth male specimen, i.e., the second male paralectotype ( Fig. 3 View FIGURE 3 ) . The MNHN male paralectotype presents two noticeable differences with the RMNH female lectotype , upon which Coutière’s (1899) and De Man’s illustrations were possibly based (e.g., Fig. 2B, C View FIGURE 2 ). Firstly , in the lectotype , the distolateral tooth of the scaphocerite is reaching only slightly beyond the anterior margin of the blade ( Figs. 1C View FIGURE 1 , 2B View FIGURE 2 ), whereas this tooth distinctly overreaches the blade in the MNHN paralectotype ( Fig. 3D View FIGURE 3 ) . Secondly, in the lectotype, the telson is somewhat broader and slightly constricted near 0.7 of its length, being generally similar to the telson of the large male from the Farasan Islands ( Fig. 4C View FIGURE 4 ), whereas in the MNHN paralectotype , the telson is somewhat narrower, distally not constricted, gently tapering, and with a faintly marked, shallow, dorsal groove on its mid-line ( Fig. 3C View FIGURE 3 ). The MNHN paralectotype also has a somewhat stouter minor chela, with distally stronger curved fingers ( Figs. 2F–H View FIGURE 2 , 3J, K View FIGURE 3 ), which, however, is likely due to the genus-typical sexual dimorphism of the minor cheliped. Considering the variation in the development of the distolateral tooth relative to the blade observed in the Saudi Arabian material herein assigned to A. djeddensis based on colour pattern and/or molecular analyses ( Figs. 4A View FIGURE 4 , 8A View FIGURE 8 , 9B View FIGURE 9 ), the difference in this character between the lectotype and the MNHN paralectotype seems to fall within the normal intraspecific variation for the species (see also Banner & Banner 1981: fig. 1c–j). It is also possible that in some larger individuals, such as the lectotype , the distolateral tooth gets blunter with age, i.e., its tip erodes at each moult ( Figs. 1B View FIGURE 1 , 2B View FIGURE 2 ). Whatever the case may be, all future morphological comparisons involving A. djeddensis should be made based on the RMNH lectotype .

Alpheus djeddensis also appears to be variable in the colour pattern ( Figs. 6–10 View FIGURE 6 View FIGURE 7 View FIGURE 8 View FIGURE 9 View FIGURE 10 ). Of particular interest is the variation in the general colour of the banding on the carapace and pleon, ranging from olive-brown ( Figs. 6 View FIGURE 6 , 7 View FIGURE 7 ) to dusky blue ( Fig. 9 View FIGURE 9 ), and in the form of banding, much more contrasting in younger individuals ( Figs. 7–9 View FIGURE 7 View FIGURE 8 View FIGURE 9 ) and more diffuse, with smaller or more interrupted bands, in larger adults ( Figs. 6 View FIGURE 6 , 10A View FIGURE 10 ). Nonetheless, the main diagnostic features of the colour pattern of A. djeddensis can be summarised as following: (1) carapace and pleon with transverse banding, on pleon with two bands per pleonite, fifth pleonite not forming a closed circle dorsally; (2) carapace flanks without large dark patch; (3) antennular stylocerite mostly blue, except for small proximal area; (4) antennular and antennal flagella intense dark blue; and (5) second to fifth pereiopods blue with bright pink or red-orange markings near articulations ( Figs. 6–10 View FIGURE 6 View FIGURE 7 View FIGURE 8 View FIGURE 9 View FIGURE 10 ).

The goby partner specificity of A. djeddensis remains to be clarified, although based on the presently available evidence and personal field observations in Thuwal, Saudi Arabia, the preferred goby partner appears to be Cryptocentrus caeruleopunctatus ( Fig. 10 View FIGURE 10 ). Associations of A. djeddensis with C. cryptocentrus are also likely as this goby was frequently observed (and collected on a few occasions) at the collection sites of A. djeddensis near Thuwal (see also Ryanskiy 2022: 103, colour photograph of C. cryptocentrus in Egypt). Associations of A. djeddensis with C. lutheri Klausewitz cannot be confirmed at this stage as none of the snapping shrimps associated with C. lutheri , e.g., the species listed under the name “ A. djiboutensis ” in Karplus et al. (1972a, 1981), can be reliably referred to A. djeddensis , as defined in the present study (see also below).