Dispio anauncinata, Delgado-Blas, Víctor Hugo & Díaz-Díaz, Oscar, 2016

Delgado-Blas, Víctor Hugo & Díaz-Díaz, Oscar, 2016, Redescription of two species and five new species of Dispio Hartman, 1951 (Spionidae: Polychaeta) from the eastern Pacific Coast and Caribbean Sea, with a review of the genus, Zootaxa 4178 (2), pp. 151-181: 160-163

publication ID

http://doi.org/10.11646/zootaxa.4178.2.1

publication LSID

lsid:zoobank.org:pub:C533EE2A-5831-49A2-A4ED-2E7CD94EC663

persistent identifier

http://treatment.plazi.org/id/CA1187AD-CA41-E85A-FF30-A514D9B1FD79

treatment provided by

Plazi

scientific name

Dispio anauncinata
status

sp. nov.

Dispio anauncinata  sp. nov.

Figure 4View FIGURE 4 A –Z

Material examined. Northeastern Pacific , California, Southern California Bight, Santa Barbara County, Carpinteria , Carpinteria State Beach , 34.388ºN, 119.516ºW, low intertidal zone, sand, sand patches between rocks, oil slicks on sand and in tide pools, 15 cm diameter infaunal core, Sta. 315 CARPIN_4235QX, Rep 2, coll Marine Pollution Studies Lab-Moss Landing Marine Laboratories, 15 Jul 2007, holotype ( LACM-AFH POLY 6242)GoogleMaps  .— California, Southern California Bight, Los Angeles County, 34º10′15″N, 118º46′50″W, 28.8 m, very fine silty sand 1.65 miles bearing 051.5ºT (true north) from Point Dume, Van Veen grab, R/ V Vel ero IV Sta. 6749-59, coll. Allan Hancock Foundation, 7 Dec 1959, i.d. Olga Hartman, 3 paratypes (+ four fragments: two posterior fragments, one with 35 chaetigers and the other with 16 chaetigers and a pygidium, and two middle fragments, one with 15 chaetigers, and the other with 8 chaetigers) ( LACM-AFH POLY 6239)GoogleMaps  .

Description. Holotype broken into four fragments, totaling 128 chaetigers, 36 mm long, 1.5 mm wide. Color in alcohol off-white, opaque. Paratype incomplete with 76 chaetigers, 26 mm long, 1.8 mm wide. Paratypes incomplete with 23–28 chaetigers, 2.0–9.0 mm long, 0.4–1.4 mm wide. Color in alcohol light brown. Body without any other pigmentation. Prostomium peanut-shaped, pointed anteriorly, widest above eyes, slightly narrow at tip of peristomium ( Fig. 4View FIGURE 4 A), posteriorly tapering to a short, blunt caruncle forming a longitudinal nuchal ridge, extending to near end of chaetiger 1 ( Fig. 4View FIGURE 4 A). Two pairs of dark brown subdermal eyes: one pair of small, lateral kidney-shaped eyes, one pair of rounded, medial eyes (Holotype) ( Fig. 4View FIGURE 4 A); one small paratype with red eyes (0.4 mm wide); one paratype of medium size with black eyes (1.4 mm wide), eyes in nearly straight line between base of palps; one larger paratype without eyes. Palps long, extending to chaetigers 8–12; palps with a single band of transverse rows of cilia on one side of ventral ciliated groove; one paratype with slightly pigmented dark brown palps on anterior side ( Fig. 4View FIGURE 4 B); palpal sheath large, smooth ( Fig. 4View FIGURE 4 B); palps lost in holotype. Peristomium long, expanded laterally ( Fig. 4View FIGURE 4 A), partially enveloping prostomium and extending around base of palps, forming large lateral wings ( Fig. 4View FIGURE 4 A, E), separated from chaetiger 1.

All notopodial postchaetal lamellae almost completely fused with branchiae with free and pointed tips on anterior chaetigers ( Fig. 4View FIGURE 4 C); partially fused on middle and posterior chaetigers ( Fig. 4View FIGURE 4 D); notopodial postchaetal lamellae of chaetigers 1–2 shifted dorsally and serrated. Lamellae of chaetiger 1 bearing 2–6/1–5 (holotype: 2 right, 1 left) digitiform lobes along distal margin, basal margin rounded ( Fig. 4View FIGURE 4 E); notopodial lamellae of chaetiger 2 with 0–2 / 1–3 (holotype: 0/1 right, left side) digitiform lobes along distal margin ( Fig. 4View FIGURE 4 F), middle margins ruffled, basal margin wider, rounded; lamellae of chaetigers 3–21/29 slender, long, with ruffled distal margin, basal margin rounded ( Fig. 4View FIGURE 4 F, G); subsequent lamellae entire, with narrow distal and middle margins, basal margin longer, narrower, rounded ( Fig. 4View FIGURE 4 C); becoming slightly ruffled again on chaetigers 36–61 giving appearance of a notch in middle of margin, ruffles gradually diminishing and lamellae becoming completely entire on posterior chaetigers (holotype); ventral margin of lamellae short, slender triangular from chaetigers 33–37 (37 in holotype); from chaetigers 39–40 middle lobe of lamellae becoming wider, with a long, pointed ventral edge ( Fig. 4View FIGURE 4 H); subsequent parapodia decreasing gradually in size, from chaetiger 83 middle lobe becoming narrower, smaller with short, triangular ventral edge ( Fig. 4View FIGURE 4 I). Posterior lamellae short, wider than those of middle chaetigers and pointed distally ( Fig. 4View FIGURE 4 J). Ventral and dorsal edges of notopodial and neuropodial lamellae overlapping on middle and posterior chaetigers ( Fig. 4View FIGURE 4 I). Anterior notopodial prechaetal lamellae larger, rounded ( Fig. 4View FIGURE 4 G), after chaetiger 45 becoming triangular ( Fig. 4View FIGURE 4 D) and reduced gradually in size; not fused basally with notopodial postchaetal lamellae. Each segment with a pair of dorsal C-shaped double bands of cilia with a transverse band of cilia between them ( Fig. 4View FIGURE 4 K). Lateral organs between notopodial and neuropodial postchaetal lamellae present from chaetigers 3–6 (3 in holotype), not observed on middle or posterior chaetigers.

Neuropodial postchaetal lamellae of chaetiger 1 shifted to dorsal side; neuropodial lamellae of chaetiger 1 rounded with a small papilla ( Fig. 4View FIGURE 4 E), (paratype with two papillae on right side, and one on left side of chaetiger 1 lamellae) ( Fig. 4View FIGURE 4 F); neuropodial lamellae of chaetiger 2 with a papilla ( Fig. 4View FIGURE 4 E, L); lamellae of chaetigers 3 – 10 rounded, wider ( Fig. 4View FIGURE 4 F –G), becoming more rectangular, wider with rounded edges from chaetigers 13 to 32/36, with upper border gradually elongating to form a point from around chaetigers 37–39 ( Fig. 4View FIGURE 4 H); subsequent parapodia becoming smaller with triangular upper and lower borders ( Fig. 4View FIGURE 4 I), neuropodia of posterior chaetiger triangular and shifted dorsally ( Fig. 4View FIGURE 4 M) with lower border rounded up to end of body. Neuropodial prechaetal lamellae small, rounded, wide ( Fig. 4View FIGURE 4 G); middle region smaller and decreasing gradually in size on posterior chaetigers, all lamellae not basally fused with neuropodial postchaetal lamellae.

Branchiae present from chaetiger 1, continuing to end of body; all branchiae tapered, long, smooth, almost completely fused to notopodial lamellae, branchial tips free, distally pointed on all chaetigers ( Fig. 4View FIGURE 4 C), longer than notopodial lamellae ( Fig. 4View FIGURE 4 K). Each branchia with a dense band of cilia along inner edge. Accessory branchiae present from chaetigers 11–21 (11 in holotype), initially as a simple long digitate lobe that arises from dorsolateral side of body behind notopodial base ( Fig. 4View FIGURE 4 H –I); number of lobes gradually increasing to 2 or 5 in middle and posterior chaetigers ( Fig. 4View FIGURE 4 C); arranged in one or two rows (4 or 5 on anterior row, 2 or 3 on posterior row). Last 16 segments without accessory branchiae.

Notochaetae of chaetiger 1 arranged in dorsal tuft and ventral fascicle; dorsal tuft with 20–30 long, smooth, alimbated, slender capillaries extending beyond margins of notopodial lamellae to between palps; ventral fascicle arranged in two rows: anterior row comprised of short, slender, alimbated, smooth capillaries; posterior row with same structure, but capillaries longer than in anterior row; ventral fascicle with fewer capillaries than dorsal tuft. Notochaetae of chaetiger 2 and subsequent chaetigers arranged in same way as those on chaetiger 1, except that capillaries of dorsal tuft long, slender, striated, unilimbated dorsal capillaries ( Fig. 4View FIGURE 4 N). Ventral fascicle with anterior row of unlimbated capillaries, stout, heavily reticulated in middle and at distal end of shaft, striated in middle and at basal end of shaft ( Fig. 4View FIGURE 4 O, O ´); sheathes of ventral chaetae thicker than dorsal chaetae ( Fig. 4View FIGURE 4 O ′); capillaries in posterior row slender, smooth, bilimbated distally and striated in middle and at basal end of capillary shafts ( Fig. 4View FIGURE 4 P); capillaries longer than those of anterior row; anterior chaetae on middle chaetigers with same structure except that anterior row comprised of reticulated, long, alimbate capillaries, and posterior row of slender, smooth, alimbated capillary chaetae; posterior chaetigers with dorsal tuft of long, slender, smooth, distally unilimbated capillaries ( Fig. 4View FIGURE 4 Q). Notopodial hooded hooks absent.

Neurochaetae of chaetiger 1 arranged in two rows: anterior row comprised of slender, slightly reticulated, granulated, unilimbate capillaries, striated in middle and at basal end of shaft ( Fig. 4View FIGURE 4 R); posterior row of long, smooth, slightly striated, alimbate capillary chaetae ( Fig. 4View FIGURE 4 S); capillaries in anterior row shorter than those in posterior row; in addition, a ventral tuft of four slender, shorter, smooth alimbated capillaries ( Fig. 4View FIGURE 4 T) is located in position of sabre chaetae. Neurochaetae of chaetiger 2 and subsequent chaetigers similar to those of chaetiger 1, except that chaetae in anterior row stout, heavily reticulated; ventral tuft with 2–3 longer, stouter, heavily reticulated, granulated, unilimbated sabre chaetae ( Fig. 4View FIGURE 4 U). Sabre chaetae longer from chaetiger 11. Chaetae on middle chaetigers arranged in two rows: an anterior row of hooded hooks ( Fig. 4View FIGURE 4 V, V ′) and a posterior row of long, smooth, unilimbated, wide capillary chaetae ( Fig. 4View FIGURE 4 W). Uni-bidentate neuropodial hooded hooks from chaetigers 17 – 25 (24 in holotype), up to 5 – 7 present per neuropodium, accompanied by very slender, small, smooth, alimbated capillary chaetae. Unidentate hooks ( Fig. 4View FIGURE 4 V) on anterior chaetigers and uni- or bidentate hooks on middle and posterior chaetigers ( Fig. 4View FIGURE 4 V, V ′) (same chaetiger); hooded hooks opened distally ( Fig. 4View FIGURE 4 V, V ′), shaft almost straight ( Fig. 4View FIGURE 4 V, V ′). In small paratypes almost all hooks bidentate ( Fig. 4View FIGURE 4 V ′).

Pygidium with pigmented dark-brown midventral flap and two pairs of long cirri ( Fig. 4View FIGURE 4 X).

Remarks. Dispio anauncinata  sp. nov. is similar to D. uncinata  in that the first two notopodial and neuropodial postchaetal lamellae are deeply serrated with digitiform papillae. Dispio anauncinata  sp. nov. is also similar to Dispio longibranchiata  sp. nov. in having a short, blunt caruncle, eyes with the same shape and arrangement, and the first notopodial postchaetal lamellae with digitiform papillae. However, Dispio anauncinata  sp. nov. can be distinguished from D. uncinata  and Dispio longibranchiata  sp. nov. in that it has a peanut-shaped prostomium, the ventral and dorsal edges of the notopodial and neuropodial lamellae overlap on the middle and posterior chaetigers, and the neuropodial lamellae are rounded on chaetiger 3; with, Dispio anauncinata  sp. nov. can also be distinguished from D. uncinata  in that the former has a blunt caruncle, the notopodial lamellae of chaetiger 3 have ruffled distal margins, the notopodial lamellae gradually become slightly notched on the middle edge of lamellae on chaetigers 36–61, the pygidium is pigmentated dark-brown with a midventral flap and two pairs of long cirri, and other differences are provided in the Table 1 and key; with, Dispio anauncinata  sp. nov. can also be distinguished from D. longibranchiata  sp. nov. in that it has a larger peristomium and lateral wings, notopodial lamellae of chaetiger 2 with papillae, notopodial lamellae on chaetigers 39 – 40 with a pointed ventral border, neuropodial lamellae of chaetigers 1 – 2 with papillae, branchiae that do not overlap, notochaetae of anterior and middle chaetigers with stout capillaries heavily reticulated in the middle and distal end of the shaft and striated in the middle and basal end of the shaft, and unilimbated capillaries on the anterior row. Dispio anauncinata  sp. nov. is similar to D. panamensis  in having the first two notopodial and neuropodial postchaetal lamellae deeply serrated with digitiform papillae. However, D. anauncinata  differs from D. panamensis  in that the former has a peanut-shaped prostomium, a short, blunt caruncle, notopodial lamellae of chaetiger 3 with ruffled margins, rounded and smooth neuropodial lamellae on chaetiger 3, notopodial and neuropodial lamellae without overlapping or touching edges on anterior chaetigers, branchiae that do not overlap each other on anterior chaetigers, and distally pointed branchial tips on all chaetigers. Further differences between this new species and the other species examined are provided in the key and Table 1.

Ecology. Dispio anauncinata  sp. nov. was found in low intertidal zones, sand, sand patches between rocks, oil slicks on sand and in tide pools, collected with a 15 cm diameter infaunal core.

Geographical distribution. North Pacific , USA, California, Southern California Bight, Santa Barbara County, Carpinteria , Carpinteria State Beach , 34.388ºN, 119.516ºWGoogleMaps  .

Etymology. The specific name is from the Greek ana - meaning similar to D. uncinata  .

Kingdom

Animalia

Phylum

Annelida

Class

Polychaeta

Order

Spionida

Family

Spionidae

Genus

Dispio