Ogleus pilarae, Morales-Núñez, Andrés G. & Heard, Richard W., 2013
Morales-Núñez, Andrés G. & Heard, Richard W., 2013, Ogleus pilarae, a new genus and species of leptocheliid tanaidacean (Crustacea: Peracarida: Tanaidomorpha) from the tropical Northwest Atlantic with observations on the genus Pseudonototanais Lang, 1973, Zootaxa 3737 (4), pp. 454-472 : 459-467
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Ogleus pilarae , n. sp.
Material examined. Holotype: Adult male, length 2.0 mm, (USNM 1190199), 18 ˚ 16 ’ 21.81 ’’N, 65 ˚ 19 ’09.01’’W, 3.2 km Southwest of Culebra Island, Puerto Rico, depth 28 m, collected between October 2002 and October 2003. Paratypes (same collection data as for holotype): four females (USNM 1190200); one male and two females (GCRL 06524). Additional specimens from the type locality are in the collection of the authors.
Diagnosis. Male: antennule having six flagellar articles; article- 1 wider than long, much shorter than article- 2; articles 1 to 5 bearing aesthetascs, terminal article- 6 minute, not fused with last flagellar article, with simple setae. Uropod with endopod having five articles or incipient articles, article- 5 distinctly longer than article- 1; exopod appearing unarticulated, small, not reaching past article- 1 of endopod. Female: Maxilliped having distal margin of basis with three to four pairs of long, simple setae. Uropod similar to that of male.
Etymology. Genitive. Named in honor of senior author’s fiancée, Maria Del Pilar Sierra-Gómez, in appreciation for her support and encouragement in his study of the Tanaidacea .
Type locality. 18 ° 16 ’ 21.81 ’’N, 65 ° 19 ’09.01’’W, 3.2 km Southwest of Culebra Island, off eastern Puerto Rico, depth 28 m, soft substrata (sand).
Distribution. Puerto Rico, presently known only from the type locality.
Description. Adult Female.
Body ( Figs. 2 View FIGURE 2 A −B): Length about 2.7 mm, about 12.5 times width.
Cephalothorax (Fisg. 2 A −B): About 20 % of total body length, longer than first two pereonites combined, about 1.5 times width; ocular lobes with eyes having visual elements present (pigmented with 11–13 ommatidia). Lateral seta on mid-length ( Fig. 2 View FIGURE 2 B).
Pereon ( Figs. 2 View FIGURE 2 A −B): About 65 % of total body length; pereonites 1, 2, 3, 5 and 6 sub-rectangular, wider than long; pereonite- 4 rectangular, longer than wide.
Pleon ( Figs. 2 View FIGURE 2 A −B): About 10 % of total body length; combined length of pleonites 1 to 5 about equal to that of pereonite- 4; all pleonites subequal, much wider than long, with three simple epimeral setae ( Fig. 2 View FIGURE 2 B). Pleotelson ( Figs. 2 View FIGURE 2 A −B): 5 % of total body length, slightly shorter than pleonite- 1; pair of subapical simple setae and pair of simple setae on apical lobe.
Antennule ( Figs. 3 View FIGURE 3 A–B): Relatively long (slightly longer than 2 / 3 of total length of cephalothorax), with three distinct articles and minute terminal article. Article- 1 length about 1.25 times that of article- 2 and - 3 combined, with three clusters of three sensory setae along lateral margin and three simple setae along or near distal half of lateral margin, with simple seta on mid-ventral margin and small curved setae mediolaterally. Article- 2 about one third length of article- 1, with three simple setae, distally. Article- 3 almost half length article- 1 with three simple distal setae (unequal in length) and one aesthetasc. Article- 4 minute, with six simple setae, two twice as long as others, and one aesthetasc ( Fig. 3 View FIGURE 3 B).
Antenna ( Fig. 3 View FIGURE 3 C): Article- 1 short, asetose. Article- 2 with anteriorly directed, relatively long, distoventral thorn seta (as long as or longer than article- 2) and dorsally directed, long thorn setae on antero-dorsal margin; two small sensory setae on mid-lateral face. Article- 3 with straight, anteriorly directed, spinose process on dorsodistal margin. Article- 4 about equal in length to that of article- 2 and - 3 combined with five distal or sub-distal simple setae and simple seta on mid-dorsal margin. Article- 5 about half length of article- 4 with two simple setae distally. Article- 6 minute with five (two short and three long) simple setae.
Mouthparts: Labrum ( Fig. 3 View FIGURE 3 D): Broadly rounded and distal edge finely setose.
Mandibles ( Figs. 3 View FIGURE 3 E–G): Left mandible, incisor having upper margin just proximal to tip with four low denticles (distal and proximal-most larger than medial two); lacinia mobilis crenulate with four blunt denticles ( Fig. 3 View FIGURE 3 F). Right mandible with broad incisor with bifid tip and crenulate upper margin. Molar process with ridged, grinding surface ( Fig. 3 View FIGURE 3 G).
Labium ( Fig. 3 View FIGURE 3 H): Bilobed, setulate distally; outer distal margin of outer lobe with minute denticle.
Maxillule ( Figs. 3 View FIGURE 3 I–J): Endite with ten relatively stout distal spines ( Fig. 3 View FIGURE 3 J) and sub-distal cluster of small simple setae. Palp bearing two long terminal setae of unequal length.
Maxilla ( Fig. 3 View FIGURE 3 K): Irregularly sub-quadrate.
Maxilliped ( Figs. 4 View FIGURE 4 A–C): Basis having proximal third fused, distal margin with three, occasionally four, pairs of long simple setae ( Fig. 4 View FIGURE 4 A), finely setose lateral margin. Endites unfused with disto-lateral margins having cluster of setules and with strongly developed simple seta (reaching to distal region of palp article 2) curving medially; inner half of distal margins with two tooth-like, modified setae; inner distal margins each with stout, bidentate, denticle-like seta; inner sub-distal margin with three to four very small (apparently vestigial) coupling hooks ( Figs. 4 View FIGURE 4 B–C). Palp: Article- 1 asetose. Article- 2, outer margin having curved simple seta; inner sub-distal margin with four well-developed simple setae, three long and one short, and more proximal row of setules. Article- 3 outer margin asetose; inner margin with five strongly-developed simple setae and two smaller simple, subdistal setae. Article- 4 with seven strongly-developed, simple setae on inner and distal margin; simple seta medially on inner face.
Cheliped: Lateral view ( Fig. 4 View FIGURE 4 D): Coxal sclerite triangular, dorsally inserted, naked. Basis length about 1.6 times width, with simple seta on sub-distal, lateral face. Merus triangular, with three (2 short and 1 long) simple setae on posterior margin. Carpus length about 2.3 times width, anterior margin with small distal seta, posterior margin with three sub-distal simple setae. Propodus length about twice width; simple distal seta on margin of gap between fixed finger and dactylus; fixed finger with loose cluster of five simple setae medially. Dactylus and unguis nearly one third length of propodus. Inner face ( Fig. 4 View FIGURE 4 E): Propodus having five comb setae (anterior and posterior most longer than inner three) on anterodistal margin. Dactylus with simple seta near anteroproximal margin.
Pereopod - 1 ( Figs. 5 View FIGURE 5 A; 2 B): Distinctly larger and longer than other five pereopods. Coxa with simple seta on anterodistal margin ( Fig. 2 View FIGURE 2 B). Basis slender, length less than half that combined lengths of remaining articles, anteroproximal margin with small simple seta. Ischium wider than long with simple seta on posterior margin. Merus asetose, length about 1.5 times width, having oblique articulation with carpus. Carpus length about equal to that of merus; anterodistal margin with three simple setae, two short and one long; posterodistal margin with small simple seta. Propodus length slightly more than combined lengths of merus and carpus; width slightly less than one forth length; anterior margin with three sub-distal simple setae, two short and one long, and distal simple seta; posterior margin with two sub-distal simple setae. Dactylus elongate, styliform, longer than propodus Unguis weakly indicated, just longer than rest of dactylus.
Pereopod- 2 ( Figs. 5 View FIGURE 5 B; 2 B): Modified for constructing tube. Coxa with simple setae on anterodistal margin ( Fig. 2 View FIGURE 2 B). Basis slender, length about four fifths that of other articles combined and about five times width, simple seta on anteroproximal margin. Ischium wider than long with simple seta on posterior margin. Merus with length about 2.3 times width, small, simple spiniform seta on posterodistal margin. Carpus length about equal to that of merus, small spiniform seta sub-distally on posterior margin. Propodus length slightly more than that of carpus; anterior margin with two sub-distal simple setae, one short and one long. Dactylus and unguis together relatively short, length about 60 % that of propodus; anterior margin with simple seta medially and simple seta at junction with unguis. Unguis not curved, about half length of rest of dactylus, with minute duct opening at tip.
Pereopod- 3 ( Fig. 5 View FIGURE 5 C): Similar in form and function to pereopod- 2, except by basis having two broom setae on anteroproximal margin. Carpus with simple seta on posterodistal margin.
Pereopod- 4 ( Figs. 5 View FIGURE 5 D; 5 G −J): Slightly shorter than other five pereopods. Basis expanded and asetose, length about 1.3 times that of combined length of ischium-merus-carpus. Ischium wider than long with simple seta on posterior margin. Merus slightly longer than carpus, with two posterodistal small stout spiniform setae. Carpus with length about 1.2 times width; anterodistal margin bearing simple seta; posterodistal margin with three stout spiniform setae each having small outer setule ( Fig. 5 View FIGURE 5 G). Propodus length slightly less than that of merus; anterior margin with small spiniform seta distally, one simple seta about as long as dactylus and unguis combined, and two pectinate spiniform setae (1 short and stout) of varying length on anterodistal margin ( Figs. 5 View FIGURE 5 H −I, respectively); posterior margin with two short, stout pectinate, spiniform seta sub-distally ( Fig. 5 View FIGURE 5 J). Dactylus almost half length of propodus; unguis, curved and partially fused, about half length dactylus.
Pereopod- 5 ( Fig. 5 View FIGURE 5 E): Similar to pereopod- 4, except about 1.1 times longer.
Pereopod- 6 ( Fig. 5 View FIGURE 5 F): Basis broad, length slightly more than two thirds that of combined lengths of remaining articles, two simple setae on margin. Ischium wider than long, with two mid-anterior simple setae. Merus about same length as carpus with two subdistal spiniform setae near posterior margin. Carpus with length about 1.3 times width; posterodistal margin having three stout spiniform setae, with row of setules on distal half of posterior margin. Propodus length about same as that of merus; anterior margin with four simple setae and three pectinate spiniform terminal or sub-terminal setae; posterior margin with two short, stout pectinate, spiniform seta subdistally. Dactylus smaller than those of pereopods 4 and 5, short, about one third length of propodus, unguis, curved and fused
Pleopods ( Fig. 5 View FIGURE 5 K): Five similar, well-developed, biramous pairs. Basal article broad, asetose. Rami lengths slightly more than twice width, both with inflated plumose seta on proximal inner margin adjacent to articulation with basis. Endopod with inner and distal margins usually bearing nine long plumose setae, distalmost seta modified, greatly attenuated and filament-like distally; with strongly developed plumose seta on mid-lateral margin. Exopod with inner and distal margins bearing about 18 long plumose setae, outer margin asetose.
Uropod ( Fig. 5 View FIGURE 5 L): Biramous. Basis with simple seta on sub-distal outer margin. Exopod unarticulated, slightly shorter than first article of endopod, with simple seta on outer proximal margin, two distal simple setae (outer seta longest, about equal to combined lengths of basis and exopod; inner seta about one third length of outer). Endopod with five articles or incipient articles. Article- 1 with length about 2.3 times width, with inner and outer, small simple setae distally. Article- 2 length about 2.0 times width, with two, one outer and one inner, simple setae distally. Article- 3 length about 4.0 times width, with two long simple setae and two sensory setae on sub-distal margin. Article- 4 length about 2.4 times width, with one long simple seta on inner sub-distal margin. Article- 5 length about 4.2 times width, with three simple setae (2 long and 1 short) and two sensory setae on distal margin, last article distinctly longer than first.
Male. Body ( Figs. 6 View FIGURE 6 A − B) smaller than female, length 2.0 to 2.2 mm, slender, about 12 times width.
Cephalothorax ( Figs. 6 View FIGURE 6 A −B): Narrower than that of female anteriorly, about 25 % of total body length, over twice as long as wide, slightly longer than combined lengths of pereonites 4 and 5, sub-rectangular with simple seta on each mid-lateral face. Ocular lobes with well-developed, pigmented eyes, with visual elements present.
Pereon ( Figs. 6 View FIGURE 6 A −B): About 60 % of total body length; 1, 2, 3 and 6 sub-rectangular, wider than long; pereonite- 5 quadrate, about as long as wide; pereonite- 1 with simple seta distally on each lateral margin.
Pleon ( Figs. 6 View FIGURE 6 A −B): About 15 % of total body length; combined lengths of pleonites 1 to 5 equal to combined lengths pereonites- 1 and - 2; all pleonites sub-equal, much wider than long, with two short epimeral simple seta ( Fig. 6 View FIGURE 6 B).
Pleotelson ( Figs. 6 View FIGURE 6 A −B): About same length as pleonite- 5, with four apical simple setae, and single lateral small on each side; about 2 to 3 % of total body length.
Antennule ( Figs. 7 View FIGURE 7 A–B): Peduncle with three distinct, unfused articles. Article- 1 with length slightly more than 2.5 times width, with two dorsal unequal simple setae distally; with sensory seta on middle lateral margin and three unequal simple setae on distal margin. Article 2 -with length about 2.5 times width, with two dorsal simple setae distally; with two simple setae on distal margin. Article- 3 about half length of article- 2, with two dorsal simple setae distally. Flagellum with six articles. Articles 1 to 5 each bearing distal row of aesthetascs; articles 1–4 with seven to eight and article- 5 with two aesthetascs. Article- 1 reduced, wider than long, distinctly shorter than articles 2, 3 or 4. Article- 4 with length about equal to that of articles- 5 and - 6 combined. Article- 5 small, but distinctly larger than article- 6. Article- 6 minute with three simple setae of varying length ( Fig. 7 View FIGURE 7 B).
Mouth parts: Vestigial, appearing non-functional.
Maxilliped: Reduced, apparently non-functional, Remnants of endites with one or two setae; palps fused, forming attenuated lobe ( Fig. 7 View FIGURE 7 C).
Cheliped: Lateral aspect ( Fig. 7 View FIGURE 7 D): Coxal sclerite triangular. Basis with length about 1.6 times width, one simple seta on mid-lateral margin. Merus sub-rectangular with anterior lobe, margin with two simple setae, anterior-most longest. Carpus with broad lateral face, width about four-fifths length. Chela forcipate; fixed finger directed downward, nearly at right angle to posterior (ventral) margin of propodus; dactylus reaching to or beyond tip of fixed finger. Propodus, excluding fixed finger, with length about twice width, margin with acute process distally, and simple setae near base of dactylus; fixed finger with low dentate tooth midway along incisive margin, weak cluster of four simple setae between tooth and sclerotized tip. Dactylus with unguis forming small subacute tip, posterior margin with row of three or four simple setae along incisive margin. Inner aspect ( Fig. 7 View FIGURE 7 E): Palm of propodus with comb of 13 setae, anterior and posterior-most setae distinctly longer than inner setae, on sub-distal margin near base of dactylus.
Pereopods- 1 ( Fig. 7 View FIGURE 7 F): Similar to female, except by minor differences in setation and proportions of articles. Pereopods 2 − 6 (not figured): Generally similar to those of female.
Pleopods (not figured): Similar to those of female, but more strongly developed for swimming. Uropod (not figured): Similar to that of female.
Remarks As discussed under the Remarks for Ogleus n. gen., the male cheliped is more or less shares characters with those of Pseudonototanais werthi , Heterotanais oerstedii and Makassaritanais angustus , the type species for their respective genera and for which females are known. Ogleus pilarae can be distinguished from these and the other leptocheliid species by a combination of characters including a male antennule having three unfused peduncular articles, five flagellar articles with the first being greatly reduced in size and ring-like with a single cluster of aesthetascs, the morphology of the male chela , uropods of both sexes having elongate endopods with five articles or incipient articles, the distal-most being about as long as or longer than other articles. A key is provided below to separate the leptocheliid males with atypical chelae.
No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.