Bruceopsis projectus, Anker, Arthur, 2010

Anker, Arthur, 2010, Description of a new genus and two new species of alpheid shrimps from Guam (Crustacea, Decapoda) *, Zootaxa 2372, pp. 389-404 : 392-399

publication ID	https://doi.org/ 10.5281/zenodo.275825
DOI	https://doi.org/10.5281/zenodo.6204662
persistent identifier	https://treatment.plazi.org/id/038E1764-FF9C-F427-FF5D-FDBCFFFA03D4
treatment provided by	Plazi
scientific name	Bruceopsis projectus
status	sp. nov.

Treatment

Bruceopsis projectus View in CoL sp. nov.

( Figs. 1 View FIGURE 1 A,B, 2–5)

Type material. Holotype: ovigerous female (cl 6.2 mm, tl 16.9 mm, dissected), FLMNH UF Arthropoda 10948 , Mariana Islands, Guam, Agat Bay north of Alutom Islet , under rocks, 3-7 m, coll. H.T. Conley, 2000- 2001 (exact date unknown) .

Description. Body not particularly slender, moderately compressed ( Figs. 1 View FIGURE 1 A –B). Carapace smooth, sparsely covered with stubby setae ( Figs. 1 View FIGURE 1 B, 2B); cardiac notch well developed ( Fig. 1 View FIGURE 1 B). Frontal margin with rostrum and orbital teeth; rostrum well developed, thickened, acuminate, longer than wide, tip reaching slightly beyond distal margin of first segment of antennular peduncle, with marked lateral ridge and convex lateral margin; orbital teeth strong, sharp, anteriorly directed, reaching 0.4 length of rostrum ( Figs. 2 View FIGURE 2 A –B). Pterygostomial margin rounded, not projecting ( Fig. 2 View FIGURE 2 B). Eyes partly covered by orbital hoods, anterior-most portion of cornea visible in dorsal view; cornea well pigmented, anteromesial surface with small sharp dorsal process ( Figs. 2 View FIGURE 2 A –B). Epistomial sclerites with sharp ventrally directed teeth ( Fig. 3 View FIGURE 3 L).

Abdomen with second pleomere conspicuously enlarged in female ( Fig. 1 View FIGURE 1 B); third pleomere with small acute point at posteroventral angle (visible in Fig. 1 View FIGURE 1 B); fourth pleomere rounded, with small inconspicuous blunt projection at posteroventral angle; fifth pleomere with posteroventral region angular, not projecting; sixth abdominal somite not elongate, with unusually elongate, laterally projecting articulated plate at posteroventral angle ( Figs. 1 View FIGURE 1 B, 2E–G); posterolateral angle sharply produced ( Fig. 2 View FIGURE 2 E). Telson subrectangular, tapering posteriorly, about 1.8 times as long as wide at base; dorsal surface with two pairs of strong dorsal spines inserted at about half-length and 0.75 length of telson, respectively ( Fig. 2 View FIGURE 2 I); posterior margin slightly convex, with two pairs of posterolateral spines, lateral much shorter and slenderer than mesial; margin between posterolateral spines with 10 plumose setae ( Fig. 2 View FIGURE 2 J); anal tubercles absent.

Antennular peduncle robust; first segment with strong acuminate stylocerite, reaching or nearly reaching distal margin of second segment ( Figs. 2 View FIGURE 2 A –B); mesioventral carina with strong compressed tooth ( Fig. 2 View FIGURE 2 C); second segment subquadrate in dorsal view, much shorter than first; third segment about the same length as second; lateral flagellum thicker than mesial, bifurcating at fifth segment, secondary ramus well developed, elongate, without visible segmentation; tufts of aesthetascs present on ventral margin from third segment to tip of secondary ramus ( Fig. 2 View FIGURE 2 D). Antenna with stout basicerite, armed with anteriorly projecting, sharp distolateral tooth ( Fig. 2 View FIGURE 2 B); carpocerite short, moderately stout, not exceeding scaphocerite; scaphocerite reaching far beyond distal end of antennular peduncle, ovate, with strong, acute distolateral tooth; blade broad, with strongly convex anterior margin, slightly exceeding distolateral tooth ( Fig. 2 View FIGURE 2 A); flagellum narrower than lateral antennular flagellum, but stouter than mesial antennular flagellum.

Mouthparts ( Figs. 3 View FIGURE 3 A –G) typical for family. Mandible with bisegmented palp; incisor process well developed, with nine teeth, centrally situated teeth stronger ( Fig. 3 View FIGURE 3 A); molar process well developed, with distal ridge, protuberances and dense rows of stiff setae ( Fig. 3 View FIGURE 3 A, B). Maxillule with bilobed palp, lower lobe with moderately stout seta; upper lobe with two slender setae ( Fig. 3 View FIGURE 3 C). Maxilla with small, unsegmented palp (endopod); basal endite with deep cleft; scaphognathite rather narrow ( Fig. 3 View FIGURE 3 D). First maxilliped ( Fig. 3 View FIGURE 3 E) with palp (endopod) bearing at least two segments, distally fringed with long plumose setae; caridean lobe of exopod poorly developed ( Fig. 3 View FIGURE 3 F); epipod bilobed. Second maxilliped with moderately elongate epipod ( Fig. 3 View FIGURE 3 G).

Third maxilliped pediform, slender ( Fig. 3 View FIGURE 3 H); coxa with small lateral plate adjacent to mastigobranch, furnished with setae ( Figs. 3 View FIGURE 3 J, K); exopod well developed, almost reaching distal end of antepenultimate segment, with long flexible setae basally; antepenultimate segment slender, compressed, somewhat depressed on ventral margin, setose; penultimate segment about 0.35 length of antepenultimate segment, more than three times as long as wide; ultimate segment elongate, tapering distally with rows of serrate setae, ending in subacute corneous tip, with two stout subdistal spines ( Fig. 3 View FIGURE 3 I); arthrobranch small.

First pereiopods (chelipeds) unequal in size, asymmetrical in shape (Fg. 1B). Major cheliped moderately enlarged compared to other alpheid genera ( Fig. 4 View FIGURE 4 ); coxa with rounded dorsal protuberance near basis ( Figs. 4 View FIGURE 4 G–H), ischium small, unarmed; merus relatively slender, about five times as long as wide, unarmed, ventral margin depressed ( Fig. 4 View FIGURE 4 D), mesioventral margin distally with comb-like row of setae ( Fig 4 View FIGURE 4 F); carpus short, cup-shaped, slightly constricted dorsally, mesially with comb-like row of setae ( Fig. 4 View FIGURE 4 F); chela with palm smooth, slightly compressed, ovoid in cross-section; fingers about as long as palm, slightly curved ventrally in lateral view ( Fig. 4 View FIGURE 4 A); dactylus somewhat expanded laterally and shallowly excavated ventrally ( Figs. 4 View FIGURE 4 A –C), cutting edge with four rounded, regularly spaced teeth in distal half and one minute subdistal tooth near tip; pollex not particularly modified, cutting edge with seven rounded or subtriangular, regularly spaced teeth and two smaller subdistal teeth near tip ( Fig. 4 View FIGURE 4 E); both dactylus and pollex furnished with elongate setae ( Figs. 4 View FIGURE 4 B, E). Minor cheliped shorter than major cheliped, minor chela volume around 30–40% of that of major chela ( Fig. 1 View FIGURE 1 , cf. Figs. 4 View FIGURE 4 A, 5 A); coxa with rounded dorsal protuberance near basis ( Fig. 5 View FIGURE 5 A); ischium and merus similar to those of major chela except for size; merus with row of comb-like setae distomesially ( Figs. 5 View FIGURE 5 B–D); carpus more elongate compared to that of major cheliped, vase-shaped, slightly constricted distodorsally, mesially with comb-like row of setae ( Figs. 5 View FIGURE 5 B–D); minor chela with palm shorter than palm of major chela, smooth, slightly compressed, ovoid in cross-section; fingers somewhat shorter than palm, not curved ventrally; dactylus not especially modified, not expanded and not excavated ventrally, cutting edge with some rugosities rather than distinct teeth; pollex with cutting edge bearing four small rounded, regularly spaced teeth on proximal 0.65 of its length ( Fig. 5 View FIGURE 5 C); both dactylus and pollex furnished with fewer elongate setae or tufts of setae compared to major chela (cf. Fig. 5 View FIGURE 5 C and 4E).

Second pereiopod not elongate, slender, ischium slightly longer than merus; carpus five segmented, with ratio approximately equal to 3:1:1:1:1.7; chela longer than most-distal carpal segment, simple (Fig; 5E). Third pereiopod slender; ischium with two spines in sockets; merus almost seven times as long as wide, unarmed; carpus 0.6 times length of merus, distoventral margin with one stiff seta; propodus longer than merus, ventral margin with five slender spines in addition to distal spine adjacent to dactylus ( Fig. 5 View FIGURE 5 F); dactylus slender, conical, slightly curved, simple, dorsal margin with one slight notch distal to dactylus mid-length and one more conspicuous notch (almost forming a small tooth) at 0.65 length of dactylus ( Fig. 5 View FIGURE 5 G). Fourth pereiopod generally very similar to third. Fifth pereiopod with unarmed ischium; merus and carpus similar to those of third pereiopod, carpus without stiff seta distoventrally; propodus with at least seven spinules on ventral margin and ventrolateral brush consisting of about 11 short setal rows ( Fig. 5 View FIGURE 5 H, I); dactylus generally similar to that of third pereiopod, with two small notches on dorsal margin ( Fig. 5 View FIGURE 5 I).

First pleopod of female biramous, endopod about 0.3 length of exopod, very slender, margins fringed with setae. Second pleopod of female biramous; endopod with appendix interna. Uropod with ovate endopod, exopod ovate mesially, with straight lateral margin; protopod with strong sharp tooth on lateral lobe; diaeresis with large subtriangular tooth adjacent to distolateral tooth; distolateral spine strong, somewhat elongate ( Fig. 2 View FIGURE 2 H).

Gill/exopod formula as given for genus. Colour pattern unknown.

Size. Holotype, ovigerous female, cl 6.2 mm, tl 16.9 mm; egg diameter approximately 0.5 × 0.8 mm.

Etymology. The specific name projectus (projecting or prominent in Latin) refers to the peculiarly elongate and projecting articulated plate, a feature not observed in any other alpheid shrimp.

Ecology. The only available field notes indicate that the shrimp was collected “under rocks”, at a depth of 3–7 m, possibly on a fore reef or reef slope. However, the typical collecting style of H. T. Conley was to search for cryptic invertebrates on the extensive rubble beds of Guam, excavating piles of dead corals by hand (Dennis & Aldhous 2004), often reaching 1 m or deeper under the bed surface. This method resulted in the finding of several hitherto undescribed genera and species of crabs (e.g. Ng & Takeda 2003; Ng & Ng 2003), a ghost shrimp (Kensley 2001), and an unusual new species of shrimp from the genus Lysmata Risso, 1816 (Anker, unpubl.).

Distribution. Presently known only from the type locality, Agat Bay, north of Alutom Islet, Guam, Mariana Islands.

Remarks. See under the following species.