Periclimenaeus nielbrucei, Bruce, A. J., 2006

Bruce, A. J., 2006, Periclimenaeus nielbrucei sp. nov. (Crustacea: Decapoda: Pontoniinae), a new sponge associate from the Capricorn Islands, Queensland, with notes on related Periclimenaeus species, Zootaxa 1224, pp. 1-22 : 2-12

publication ID	https://doi.org/ 10.5281/zenodo.172627
DOI	https://doi.org/10.5281/zenodo.6258726
persistent identifier	https://treatment.plazi.org/id/727A87E6-FF8C-7B2C-D535-FBCDFBF5FC2F
treatment provided by	Plazi
scientific name	Periclimenaeus nielbrucei
status	sp. nov.

Treatment

Periclimenaeus nielbrucei View in CoL sp. nov.

( Figs 1–6 View FIGURE 1 View FIGURE 2 View FIGURE 3 View FIGURE 4 View FIGURE 5 View FIGURE 6 )

Material examined.

(1) 1 ovig. Ψ, holotype (dissected), QM W27987; 1ɗ allotype, QM W27988; 1Ψ paratype, unregistered, AJB #2670, Wreck Island, Capricorn Islands, Queensland, stn. NLB7, 6 July 1978, coll. N.L. Bruce, from unidentified sponge, unregistered. (2) 1Ψ, paratype, AJB #2727, Heron Island, Capricorn Islands, Queensland, reef flat pool at low water, 14 August 1978, coll. D. Fisk, from unidentified sponge, RMNH D.51672. Diagnosis

(2) Rostral dentition 11/0, with distal dorsal rostral teeth diverging irregularly alternatively to left and right.

Description

Holotype female ( Fig. 1 View FIGURE 1 ). Rostrum ( Fig. 2 View FIGURE 2 C) well developed, straight, slightly depressed, about 0.45 of CL, dorsal carina well developed with11 large acute teeth, first tooth preorbital, first, second, fourth and sixth teeth in median plane, other teeth diverging to left and right ( Fig. 5 View FIGURE 5 A), teeth increasing in size to seventh tooth, anterior teeth decreasing in size, tip acute, teeth with posterior border sparsely setose, lateral carinae feebly developed, ventral carina obsolete, ventral margin straight, unarmed, nonsetose.

Carapace ( Fig. 2 View FIGURE 2 A,B) smooth, with small postorbital tubercles, hepatic spine lacking, antennal spine well developed, slender, acute, marginal, with small rounded inferior orbital angle medially, anterolateral branchiostegite slightly produced, broadly rounded.

Abdomen without special features; first segment without anterodorsal lobe; sixth ( Fig. 2 View FIGURE 2 H) segment about 0.3 of CL, 1.2 times length of fifth segment, broadened, depressed, posterolateral angle small, acute, posterolateral large, strongly produced, acute.

Telson ( Fig. 2 View FIGURE 2 I) about 0.6 of CL, about 1.6 times longer than anterior width, lateral margins moderately convex, posteriorly convergent, with two pairs of subequal, submarginal dorsal spines, about 0.18 of telson length, at 0.18 and 0.5 of telson length, posterior margin ( Fig. 2 View FIGURE 2 J) broadly convex, without median point, about 0.5 of anterior margin width, lateral telson spines small, about 0.25 of dorsal spine length, intermediate spines similar to dorsal spines, about 1.35 times dorsal spine length, submedian spines more slender, setulose, longer than intermediate spines.

Antennule ( Fig. 2 View FIGURE 2 D) with proximal segment about 1.6 times central width, medial margin straight with well developed acute ventromedial tooth at 0.5 of length, distolateral angle produced, with acute distolateral tooth reaching about 0.6 of intermediate segment length, lateral margin expanded proximally, rounded, stylocerite acute, gaping, reaching about 0.5 of medial margin length, statocyst normal; intermediate and distal segments short, subequal in length, combined length about 0.6 of medial margin length, upper flagellum biramous, proximal 3 segments fused, shorter free ramua with 3 segments, about 11 groups of aesthetascs, longer ramus with 6 segments; lower ramus filiform, with 11 segments.

Antenna ( Fig. 2 View FIGURE 2 E) with basicerite laterally unarmed, with well developed antennal gland tubercle medially; carpocerite subcylindrical, flattened, about 3.2 times longer than wide, reaching to about 0.85 of scaphocerite length, merocerite and ischiocerite normal, short; scaphocerite ( Fig. 2 View FIGURE 2 F) well developed, reaching to distal margin of intermediate antennular segment, lamella broad, rounded distally, about 2.0 times longer than wide, lateral margin straight, with well developed, slender acute tooth distally, about 0.15 of scaphocerite length, at 0.85 of lateral margin length, reaching to level of distal margin of lamella.

Ophthalmic somite without small median pigment spot.

Eye ( Fig. 2 View FIGURE 2 G) with well pigmented hemispherical cornea, without accessory pigment spot, diameter about 0.16 of CL, stalk about as wide as long, width subequal to corneal diameter.

Mandible ( Fig. 3 View FIGURE 3 A) slender, without palp, molar process ( Fig. 3 View FIGURE 3 B) subcylindrical, distally oblique with pair of acute teeth posteriorly, separated by tuft of short setae, incisor process slender tapering distally, with five small acute distal teeth.

Maxillula ( Fig. 3 View FIGURE 3 C) with feebly bilobed palp ( Fig. 3 View FIGURE 3 D), upper lobe much smaller than lower, nonsetose, lower lobe with small simple terminal seta, upper lacinia short, broad, distal and ventral margins confluent, with seven short simple spines and sparse setae distally, lower lacinia slender, tapering, with four long spiniform setae distally, several slender setae ventrally.

Maxilla ( Fig. 3 View FIGURE 3 E) with simple flattened nonsetose palp, about 4.0 times longer than basal width, basal endite bilobed, lobes robust, distal lobe with about 11 simple setae distally, proximal lobe smaller and shorter, with about 8 distal setae, coxal endite obsolete, margin broadly convex, scaphognathite narrow, anterior lobe about 1.5 times longer than basal width, posterior lobe about 1.5 times longer than anterior, 3.5 times longer than basal width.

First maxilliped ( Fig. 3 View FIGURE 3 F) with palp similar to that of maxilla, basal endite fully fused with coxal, distal margin rounded, medial border straight, sparsely setose with serrulate spiniform setae, exopod normal, with slender flagellum with four plumose terminal setae, caridean lobe well developed, narrow, epipod well developed, bilobed, lobes rounded.

Second maxilliped ( Fig. 3 View FIGURE 3 G) of normal form, dactylar segment about 3.5 times longer than broad, with serrulate medial spines, propodal segment slightly produced anteromedially, sparsely setose, carpus, merus and ischiobasis without special features, exopod normal, with four plumose terminal setae, epipod small rounded, without podobranch.

Third maxilliped ( Fig. 3 View FIGURE 3 H) reaching to about end of carpocerite, with ischiomerus fully fused to basis, combined segment about 3.4 times longer than basal width, proximal medial margin expanded, convex, nonsetose, distal two thirds tapering with long simple setae medially, penultimate segment 0.5 of antepenultimate segment length, subcylindrical, 3.4 times longer than wide, sparse finely serrulate spiniform setae medially, terminal segment about 0.6 of penultimate segment length, 3.0 times longer than basal width, tapering distally, with serrulate spiniform setae, exopod with four plumose terminal setae, coxa not produced medially, with low rounded lateral plate, without arthrobranch. Thoracic sternites narrow, unarmed.

First pereiopod ( Fig. 4 View FIGURE 4 A) moderately robust, exceeding carpocerite by half carpus and chela length, chela ( Fig. 4 View FIGURE 4 B) with palm about 2.0 times as long as deep, slightly compressed, fingers ( Fig. 5 View FIGURE 5 B) about 0.65 of palm length, stout, with rounded bidentate tips ( Fig. 5 View FIGURE 5 C), cutting edges lateral, mainly entire, distally feebly denticulate ( Fig. 5 View FIGURE 5 D); carpus about 1.2 times chela length, 4.2 times longer than distal width, tapering slightly proximally; merus 1.2 times carpal length, 6.2 times longer than central width, uniform; ischium subequal to chela length; basis and coxa without special features, coxa without ventromedial process.

Major second pereiopod ( Fig. 4 View FIGURE 4 C) well developed, about 1.8 times CL, palm ( Fig. 4 View FIGURE 4 D) finely covered with small acute denticles, numerous long setae distomedially, about 1.8 times longer than maximal depth, slightly swollen proximally, oval in section, fingers ( Fig. 4 View FIGURE 4 E,F) 0.43 of palm length, sparsely setose; dactyl semicircular, 1.9 times longer than maximal depth, dorsal margin strongly convex, with stout acute hooked tip, cutting edge with well developed molar process proximally, distal cutting edge strongly concave, entire; carpus short, about 0.2 of palm length, narrow proximally, broadly expanded distally, unarmed; merus ( Fig. 5 View FIGURE 5 E) about 0.37 of palm length, robust, 1.8 times longer than central depth, about 11 acute denticles ventrally; ischium 0.75 of meral length 1.75 times longer than distal width, tapering proximally, without ventral denticles; basis and coxa normal, without special features.

Minor second pereiopod ( Fig. 4 View FIGURE 4 G) smaller than major, about 0.75 of major chela palm length, subequal to CL, palm compressed, covered with small denticles, numerous long setae distomedially, about 1.4 times longer than maximal depth, tapering strongly distally, fingers ( Fig. 4 View FIGURE 4 H,I) 0.5 of palm length, dactylus semicircular, compressed, 2.0 tomes longer than maximal depth, with strong acute hooked tip, cutting edge straight, entire, fixed finger, 1.3 times longer than deep, ventrally with numerous short setae, with small acute hooked tip, cutting edge grooved, medial edge with small blunt tooth proximally, lateral edge unarmed; carpus 0.4 of palm length, distally expanded, unarmed; merus 0.5 of palm length, 1.8 times longer than central width, ventrally unarmed; ischium 1.2 times meral length, 2.5 times longer than distal width, ischium, basis and coxa without special features.

Third pereiopod ( Fig. 4 View FIGURE 4 I) robust, exceeding scaphocerite by about half propod length; Dactylus ( Fig. 5 View FIGURE 5 F) compressed, with well demarcated unguis, curved, about 3.0 times longer than basal width, 0.5 of length of dorsal margin of corpus, ventral margin concave with six small Acute denticles, corpus about 2.1 times longer than maximal depth, nonsetose, dorsal margin feebly convex, ventral margin with small acute triangular distal accessory tooth, distal two thirds concave with 6 acute denticles, central pair larger than anterior or posterior denticles, anteroverted, posterior third convex, unarmed; propod ( Fig. 4 View FIGURE 4 J) about 0.4 of CL, about 3.8 times longer than maximal depth, tapering distally, sparsely setose, with pair of short stout distoventral spines, 7 similar spines spaced along ventral border; carpus 0.78 of propod length, 2.7 times longer than distal width, tapering slightly proximally, unarmed; merus 1.1 times propod length, 3.0 times longer than wide, slightly broadened centrally, ventral margin with several small acute denticles distally; ischium about 0.9 of propod length, 3.0 times longer than distal width, tapering proximally, with single small acute ventral denticle distally; basis and coxa without special features.

Fourth pereiopod generally similar to third; dactyl more elongate( Fig. 5 View FIGURE 5 G), about 0.5 of propod length, unguis similar to third pereiopod, with 10 denticles, corpus 3.0 times longer than proximal width, with small acute distal accessory tooth, ventral margin mainly concave, unarmed, convex proximally with several small denticles proximally; propod about 1.1 times third propod length, 4.8 times longer than proximal width, tapering slightly distally, with single distoventral spine, 2 slender ventral spines at about 0.3 and 0.66 of propod length; merus ventrally unarmed.

Fifth pereiopod with dactylus ( Fig. 5 View FIGURE 5 I) more elongate, 1.2 times fourth dactylus length and 1.6 times third, 0.46 of propod length, unguis ( Fig. 5 View FIGURE 5 J) well demarcated, 4.5 times longer than basal width, 0.37 of corpus length, with 9 small ventral denticles, mainly distally, corpus slender, 33.3 times longer than basal width, with small acute distal accessory tooth, ventral margin sinuous, without`denticles; propod ( Fig. 5 View FIGURE 5 H) about 1.25 times length of third propod, slightly bowed, 6.5 times longer than wide, with single distoventral spine, 2 slender spines distally; merus ventrally unarmed.. Pleopods without special features.

Uropod ( Fig. 2 View FIGURE 2 K) with protopod unarmed, exopod 1.8 times longer than broad, with lateral margin slightly convex, unarmed, with well developed acute distolateral tooth ( Fig. 2 View FIGURE 2 L) with large mobile spine medially, about 3.0 times tooth length, extending well beyond posterior margin of lamella, endopod about 0.95 of exopod length, 2.0 times longer than broad.

Ova normal, 2 only.

Allotype male. Generally similar to holotype, slightly smaller.

Rostrum with dentition of 11/0, with similarly divergent dorsal teeth. Second pereiopods are also similar but relatively larger and more robust.

Ambulatory pereiopods similar to holotype. Third pereiopod dactyl ( Fig. 6 View FIGURE 6 B) 3.5 times longer than proximal depth, 0.35 of propod length, unguis ( Fig. 6 View FIGURE 6 C) 0.45 of corpus length, with 8 small acute ventral denticles, corpus with well developed acute distal tooth, 8 well developed anteroverted ventral denticles, propod ( Fig. 6 View FIGURE 6 A) 4.5 times longer than proximal depth, with well developed pair of distoventral spines, smaller pair of preterminal ventral spines, six single ventral spines, smaller, except distinctly larger third spine. Fifth pereiopod dactyl ( Fig. 6 View FIGURE 6 E) 5.0 times longer than proximal depth, about 0.45 of propod length, unguis ( Fig. 6 View FIGURE 6 F) 0.31 of corpus length, with 10 small acute ventral denticles, corpus with small acute distal tooth, ventral margin concave with 2 minute proximal denticles, propod ( Fig. 6 View FIGURE 6 D) bowed, about 7.3 times longer than proximal depth, with single small slender distoventral spine, 1 smaller preterminal ventral spine, rest of ventral margin unarmed.

First pleopod ( Fig. 6 View FIGURE 6 G) with exopod subequal to basipodite length; endopod ( Fig. 6 View FIGURE 6 H) half basipod length, 3.3 times longer than width, medial margin straight, with 7 short slender spinules, lateral margin convex with single short subterminal plumose seta.

Second pleopod ( Fig. 6 View FIGURE 6 I) similar, slightly larger, endopod ( Fig. 6 View FIGURE 6 J) about 0.8 of basipodite length, 4.0 times longer than wide, with appendices ( Fig. 6 View FIGURE 6 K) at 0.3 of medial margin length, appendix interna far exceeding corpus of appendix masculina, about 0.33 of endopod length, with few distomedial cincinnuli, corpus of appendix masculina short, about 0.4 of appendix masculina length, 3.5 times longer than width, with long stout setulose terminal spiniform seta, about 2.2 times corpus length, single more slender preterminal distomedial spiniform seta, about 0.8 of terminal spine length.

Paratype female. No significant differences from holotype. Rostral dentition 11/0, fifth pereiopod dactyl with single minute, almost indiscernible denticle proximally on corpus, distal accessory tooth smaller, unguis with 7 small ventral denticles.

Measurements (mms)

(1) Female holotype, CL, 2.4; carapace and rostrum, 3.2; total body length (approx.), 9.0; major second pereiopod chela, 3.2; minor second pereiopod chela, 2.15; length of ovum, 0.5. Male, allotype, CL, 1.7; carapace and rostrum, 2.6; total body length (approx.), 7.0; major second pereiopod chela, 3.2; minor second pereiopod chela, 2.0. (2) female paratype, CL 1.7.

Host

Unidentified sponges [Porifera].. Etymology

Named after my son, Dr Niel L Bruce, in appreciation of his help over many decades.

Systematic position

Periclimenaeus nielbrucei is most closely related to P. holthuisi Bruce (see Bruce, 1969). It shares with this species the following characters: supraorbital tubercles present, first abdominal segment lacking anterodorsal lobe, second pereiopods with cutting edges of fingers distally entire, minor second pereiopod with fixed finger not grooved along cutting edge, ambulatory dactyl biunguiculate, with denticulate unguis and corpus ventrally denticulate. It differs in the following characters: dorsal rostral teeth divergent, not linear, dentition 11/0, not 7/1; dactyl of third pereiopod with simple accessory tooth, not strongly compressed, multidenticulate; dactyls of fourth and fifth pereiopods increasingly elongate with strong reduction of ventral denticles of corpus, versus dactyls of third to fifth pereiopods all generally similar.

Remarks

The characteristic rostrum that immediately identifies this species might have been considered to be the result of abnormal regeneration after trauma or a genetic abnormality if based on a single specimen. Its occurrence in four specimens in two localities clearly indicated that it is a normal morphological feature of this species.