Rutiderma rostratum Juday 1907

Rutiderma rostratum Juday, 1907

Rutiderma rostrata Juday, 1907:147, pl. 20: figs. 8–13.

Not Rutiderma rostrata.—Hartmann, 1959:195, 196, 198, 199 [≠ R. hartmanni Poulsen, 1965:32].—Poulsen, 1965:18, figs. 2, 3.—McKenzie, 1965:62, fig. 2, pl. 1: fig. 3.

HOLOTYPE.—Female, length 1.2 mm, height 0.9 mm; unique specimen, not extant.

TYPE-LOCALITY.—Glorietta Bight, San Diego Bay, 30 Jun 1903.

MATERIAL.—USNM 158222 (BM 17), 1 adult female from off Oxnard, California, sta B1-C, Jun 1974, about 22 m; USNM 158228 (BM 17A), 1 adult male from same sample. USNM 158352, 6 specimens including 2 ovigerous females, from off Monticeito, California, sta C + D, Jan 1973, about 11 m (30–40 ft), sand substrate.

SUPPLEMENTARY DESCRIPTION OF ADULT FEMALE (Figures 1, 2).—Carapace more-or-less ovoid in lateral view with overhanging rostrum; caudal process narrow, not projecting posteriorly (Figure 1).

Ornamentation: Two faint horizontal ribs present, one dorsal and one ventral to central adductor muscle attachments (Figure 1); valve surface with abundant small oval fossae; anterior edge of rostrum with minute scallops (Figure 1).

Infold: Infold of rostrum with 7–9 bristles forming row parallel to anterior margin (Figure 2a); 2 short bristles present at inner edge of incisur; anteroventral infold and anterior end of infold of ventral margin with total of about 8 bristles paralleling valve edge; posteroventral infold including caudal process with about 19 bristles (about 12 of these on caudal infold) (Figure 2b); infold of caudal process of left and right valves similar.

Selvage: Wide lamellar prolongation fringed along anterior and ventral margins except along posterior end of latter; prolongation narrower and without fringe along edge of caudal process and posterior margin of valve; selvage divided at inner end of incisur and at minute bristle on edge of caudal process (Figure 2b).

Size: USNM 158222, length 1.32 mm, height 0.91 mm. USNM 158352, 2 specimens: length 1.40 mm, height 0.99 mm; length 1.33 mm, height 0.95 mm.

First Antenna (Figure 2d): 1st joint with few medial and lateral spines forming rows. 2nd joint with 2 spinous bristles (1 dorsal, 1 lateral); medial and lateral surfaces with long hairs forming 3 rows on dorsal margin proximal to dorsal bristle; lateral surface with short spines forming row near distal margin. 3rd joint small, fused to 4th, with 3 bristles (2 dorsal, 1 ventral); long 4th joint with 3 bristles (1 dorsal, 2 ventral; longer of ventral bristles with long hairs near middle). Sensory bristle of long 5th joint with 1 small proximal filament and minute process at tip; small lateral spines near base of bristle. Minute 6th joint with short spinous medial bristle. 7th joint: a-bristle spinous, about same length as bristle of 6th joint; b-bristle longer than a-bristle, with minute process at tip; c-bristle about same length as sensory bristle of 5th joint, with 1 small faint proximal filament and minute process at tip. 8th joint: d -and e-bristles bare with blunt tips not reaching tip of sensory bristle; f-bristle stout, almost same length as d-bristle, with minute process at tip; g-bristle slightly longer than c-bristle, with short proximal filament, a few faint spines near middle, and minute process at tip. [Juday (1907:148) stated that the dorsal margin of the 2nd joint bore 1 large and 2 small setae. His illustration of the limb (pl. 20: fig. 11) has on the dorsal margin of the 2nd joint 1 small proximal seta and 1 longer distal seta. I think it probable that the small seta is a group of hairs.]

Second Antenna: Protopodite bare. Endopodite 1-jointed, with 4 small anterior bristles (Figure 2c). Exopodite: 1st joint elongate with minute medial bristle on distal margin; bristle of short 2nd joint reaching end of stem, with 2 faint spines followed by row of closely spaced blunt spines along ventral margin; bristles of joints 3–5 somewhat longer but with similar ventral spines, no hairs; bristles of joints 6–8 very long, with natatory hairs, no ventral spines; 9th joint with 6 bristles (3 long and 1 medium with natatory hairs, 2 minute, bare); joints 2–8 with spines forming row along distal margins. [The exopodite of the 2nd antenna described by Juday (1907:148) differs somewhat from that described here, but the differences could be the result of variability within the species or inaccurate observations.]

Mandible (Figure 2e): Coxale endite bifurcate, pectinate, with long hairs near base. Basale: medial side with 4 proximal bristles near ventral margin (2 pectinate, unringed; 2 slender, ringed), and 3 bristles near middle (1 small, 2 long, slender); dorsal margin with 3 bristles. 1st endopodial joint with 2 small ventral bristles and medial spines. 2nd endopodial joint with medial spines, 3 proximal dorsal bristles, 2 small distal ventral bristles, and a stout terminal claw with a small medial process at its base; the stout terminal claw with proximal dorsal tooth, a serrate dorsal flange, and a long produced tip. 3rd endopodial joint with stout claw with smoothly rounded dorsal margin and serrate ventral margin, 1 unringed flat bristle with ventral spines, 3 ringed medial bristles, and 2 ringed lateral bristles (the latter 2 bristles located lateral to base of stout claw of 2nd joint).

Maxilla (Figure 2f,g): Each of 3 endites with 2 or 3 stout pectinate bristles and 2 or 3 ringed spinous bristles (not all shown on illustrated limb). Precoxale with dorsal fringe. Coxale with short dorsal bristle with short marginal spines. Basale with 2 or 3 bristles with short marginal spines. Exopodite obscure on specimen examined but apparently with 1 short and 1 or 2 long bristles. Endopodite: 1st joint with 1 alpha-bristle, bare or with few spines, and 1 beta-bristle with short spines (endopodite is twisted on illustrated limb so that beta-bristle is in anterior position); end joint with 2 stout pectinate unringed bristles and 5 additional spinous bristles.

Fifth Limb (Figure 2h–j): Epipodial appendage with 44 bristles. Endite I with 2 bristles; endite II with 4 bristles; endite III with about 6 bristles. Expodite: 1st joint with 3 large teeth bearing secondary teeth, followed by a single pointed tooth, and then a ringed bristle; a ringed bristle present on outer margin proximal to teeth (Figure 2i); 2nd joint consisting of large flat tooth with 3 pointed lobes along inner margin; posterior side with 3 bristles (2 near proximal inner lobe, 1 near proximal outer corner of joint) (Figure 2j); 3rd joint with 2 bristles on inner lobe and 2 on outer lobe; 4th and 5th joints fused, with total of 4 bristles.

Sixth Limb (Figure 2k): 1 hirsute bristle in place of epipodial appendage. Endite I with 2 short and 1 long bristles; endite II with 1 bristle; endite III with 2 bristles; endite IV with 3 bristles. End joint with 3 anterior bristles on prominent projection, followed by 1 stout bristle with long proximal hairs and short distal spines and then 3 hirsute bristles.

Seventh Limb (Figure 2l): Each limb with 4 proximal bristles (2 on each side) and 6 distal bristles (3 on each side); each bristle with up to 6 bells and marginal spines. Terminus with opposing combs, one with about 11 teeth, other with about 6. [The 7th limb described by Juday (1907: 149) had 4 proximal and 5 distal bristles.]

Furca (Figure 2n): Each lamella with 4 stout claws followed by 2 weak secondary claws.

Bellonci Organ (Figure 2d,m): Elongate, broadening in middle part, tip broadly rounded (broadened middle part possibly with suture on each end, but could be wrinkles on specimen examined). Spines visible on organ when examined at high magnification (oil immersion, 100X objective).

Eyes (Figure 2d,m): Medial eye tapering anteriorly, lightly pigmented. Lateral eyes not observed.

Posterior of Body: Hirsute dorsal to furca.

Upper Lip (Figure 2m): Simple lobe with spines forming rows.

Y-Sclerite: Typical for genus.

Genitalia: Small oval process on each side of body anterior to furca.

Eggs: USNM 158222 with 2 large unextruded eggs.

DESCRIPTION OF ADULT MALE (Figures 3, 4).—Carapace elongate with greatest height posterior to middle; convex ventral margin and fairly linear dorsal margin except for truncate posterodorsal corner; rostrum well developed; incisur forming right or slightly obtuse angle; posteroventral corner evenly rounded with very narrow caudal process (Figure 3).

Ornamentation (Figure 3): Carapace with 2 low but distinct bulges near posterior margin but without horizontal ribs; anterior edge of rostrum with minute scallops.

Infold: Rostral infold with 7 to 9 bristles forming row parallel to anterior margin of rostrum (not all shown in Figure 4a); 2 minute bristles present at inner corner of incisur; anteroventral infold with 7 bristles forming row. Infold with well-defined inner edge but without ridge (list); infold of posterior end of ventral margin and narrow caudal process with about 22 small bristles, about 9 of these on caudal process (not all bristles shown in Figure 4b); caudal process of left and right valves similar.

Selvage (see detail in Figure 4b): Similar to that of adult female.

Size: USNM 158228, length 1.29 mm, height 0.82 mm.

First Antenna (Figure 4c): 1st joint with few spines. 2nd joint spinous on all surfaces, with 2 bristles (1 dorsal, 1 lateral). 3rd joint short, with 3 bristles (2 dorsal, 1 ventral). 4th joint about twice length of 5th joint, with medial spines and 4 bristles (1 dorsal, 3 ventral). 5th joint minute, wedged ventrally between 5th and 6th joint; sensory bristle with numerous filaments at distal end of stout proximal part (not shown on illustrated limb), and minute filament with spine at tip at base of stem just distal to stout proximal part of bristle. Long 6th joint with 1 medial bristle near distal dorsal corner. 7th joint: a-bristle smaller than, or about same size as, bristle of 6th joint; b-bristle stout, about 3 times length of a-bristle, with 2 proximal filaments with 1 or 2 spines at tip; c-bristle very long with 11 filaments; tips of filament and stem with 2 minute spines. 8th joint: d- and e-bristles bare with blunt tips, both slightly longer than b-bristle; f-bristle very long with 10 filaments; both tips of filaments and stem with 2 minute spines; g-bristle stouter and longer than b-bristle, with proximal filament with spine at tip. Tips of sensory bristle of 5th joint and b- and g-bristles with minute process.

Second Antenna: Protopodite bare. Endopodite 3-jointed (Figure 4d): 1st joint short with 5 short bristles (4 proximal, 1 distal); 2nd joint elongate with 2 slender ventral bristles (with faint marginal spines) near middle; 3rd joint elongate, reflexed on 2nd joint, with 1 short proximal bristle, 2 short slender distal bristles, and tip with about 4 ridges. Exopodite: 1st joint elongate, with spines forming rows, and with small medial bristle on distal margin; bristle of short 2nd joint reaching 6th joint, with few proximal long hairs on ventral and dorsal margin followed by short slender spines along ventral margin (spines forming groups and becoming shorter distally along bristle); 3rd joint about twice length of 2nd joint; 4th joint about three-fourths length of 2nd joint; remaining joints decreasing in size distally; bristles of joints long, with natatory hairs but no spines; 9th joint with 5 bristles (3 long and 1 medium with natatory hairs; 1 minute, bare); joint 2 with long spines forming rows along distal margin; joints 3–8 with shorter spines forming rows along distal margins.

Mandible (Figure 4e): Coxale endite represented by 2 minute spines. Basale: medial surface and ventral margin spinous; medial side with 6 bristles near ventral margin (1 long and 2 small proximal, 2 proximal to middle, 1 long near middle); dorsal margin with 3 bristles. 1st endopodial joint with medial spines and 2 ventral bristles. 2nd endopodial joint: medial surface and ventral margin spinous; ventral margin with 6 distal bristles; dorsal margin with 3 long proximal bristles. 3rd endopodial joint with long stout spinous claw and 5 short bristles. Exopodite elongate, hirsute.

Maxilla (Figure 4f): Limb reduced. Precoxale and coxale with fringe of long dorsal hairs; coxale with spinous dorsal bristle. 3 endites present, each with several weakly developed bare or spinous bristles, many without rings. Basale with 1 long and 2 short bristles (only 1 shown on illustrated limb). Exopodite with 2 long hirsute bristles. 1st endopodial joint with 1 slender hirsute alpha-bristle and 1 stouter more hirsute beta-bristle (the latter observed only on right limb, but shown as dashed bristle on illustrated left limb). End joint with 7 bristles, some unringed, all weakly developed.

Fifth Limb (Figure 4g): Endite I with 2 bristles, endites II and III each with 4 bristles. Exopodite: 1st joint with 1 proximal ringed bristle and 4 weak flat unringed bristles; 2nd joint with 3 flat unringed bristles and 2 or 3 faintly ringed bristles; inner lobe of 3rd joint with 3 bristles; outer lobe with 2 long stout hirsute bristles; fused 4th and 5th joints with 4 ringed bristles.

Sixth Limb (Figure 4h): Endite I with 3 bristles, endite II with 1 bristle, endites III and IV each with 3 bristles. End joint with 3 bristles on anterior projection followed by 4 stout hirsute bristles. 1 bristle in place of epipodial appendage.

Seventh Limb (Figure 4i): Each limb with 4 bristles in proximal group and 4 in distal group (2 bristles on each side in both groups); each bristle with up to 5 bells and marginal spines. Terminus with opposing combs with 2 or 3 bristles on each side.

Furca (Figure 4j): Each lamella with 4 strong claws followed by 2 weak claws.

Bellonci Organ (Figure 4k): Similar to that of adult female.

Eyes: Medial eye tapering distally, lightly pigmented (Figure 4k). Lateral eye well developed with dark brown or black pigment and about 11 ommatidia (exact number difficult to ascertain because of dark pigment).

Y-Sclerite (Figure 4l): Typical for genus.

Rutiderma rostratum Juday, 1907

Rutiderma rostrata Juday, 1907:142, 147–149, pl. 20: figs. 8–13 [female holotype: unique specimen, probably not extant; type-locality: “Catch 612, Glorietta Bight, San Diego Bay, June 30, 1903” (32°40.6′N, 117° 10.5′W, 0 m, locality given in Michaels and McEwen, 1915:133, 143)].—Müller 1912:35.—Lucas, 1931:399 [mentions].—Poulsen, 1965:6–9, 17, 18, 22, 31–35, 43 [Juday specimens only].

Rutiderma (Rutiderma) rostrata.—Kornicker, 1958:236, 237 [compares to R. dinochelata].

[?]Rutiderma rostrata.—Lie, 1968:274, 288, 550 [specimens not available; identification needs verification].—Lie and Kisker, 1970:2279.

Rutiderma rostratum.—Kornicker and Myers, 1981:1–10, figs. 1–4.—Kornicker, 1984:127–130, fig. 3b,d [compares to R. pax].

Not Rutiderma rostrata.—Hartmann, 1959:195, 196, 198, 199 [= R. pax Kornicker, 1983]; 1965:328 [mentions].—Poulsen, 1965:8, 11, 14, 17–22, 31–35, 38, 41, 43, figs. 2, 3 [= R. species].—McKenzie, 1965:58, 62–64, fig. 2; pl. 1: fig. 3, [= R. species].—Cohen and Kornicker, 1975:21, 26.—Kornicker, 1975b:70, 80, 678.—Kornicker and Cohen, 1981:740.

DISTRIBUTION.—Northeast Pacific: off California, U.S.A.: San Diego, Oxnard, Monticeito. [?]Northeast Pacific: Washington, U.S.A.: Puget Sound and off northern coast about 125°W between 47°N and 48°N.

HABITAT.—Benthic: 11–22 m; sand. [?]Benthic; 15–317 m; sand, sand and mud, mud, mud and gravel, fine sand mixed with shell fragments.

LIFE HISTORY AND ONTOGENY.—Female, male, 2 eggs.

ECOLOGY.—[?]Community (Lie, 1968).