Heterospio catalinensis

Heterospio catalinensis (Hartman, 1944)

Figures 21–22

Longosoma catalinensis Hartman, 1944: 322, pl. 27, figs. 1–3; 1957: 336, pl. 43, fig. 8.

Heterospio catalinensis Hartman 1969: 205–206, figs. 1–4. Vargas et al. 1985: 335; Maurer et al. 1988: 47. Not Fauchald et al. 2009: 786.

Material examined. (44 specimens) Pacific Ocean, Allan Hancock Pacific Expeditions. Off California, Santa Catalina Island, off Long Point, R / V Velero III Sta. 900-38, coll. 18 Nov 1938, dredged, 33.41°N, 118.354°W, 73 m, rock, brachiopods, and sponges, det. Olga Hartman, holotype (LACM-AHF Poly 582).— Southern California Bight, off San Clemente Island, 1.8 miles from East End Light, R / V Velero IV Sta. 4045-56, coll. 05 Apr 1956, Hayward grab, 33.311°N, 118.281°W, 104 m, (2, LACM-AHF Poly 13295); off Santa Catalina Island, 4 miles from Long Point Light, R / V Velero IV Sta. 2144-52, coll. 07 Aug 1952, Orange peel grab, 33.403°N, 118.358°W, 82 m, fine black sand, (1, LACM-AHF Poly 13296); Orange County, off Newport Beach, 1 mile from end of Balboa Pier, R / V Velero IV Sta. 2745-54, coll. 15 May 1954, Campbell grab, 33.597°N, 117.901°W, 14.6 m, gray sand, (1, LACM-AHF Poly 13297); San Diego County, off Oceanside, 0.25 miles from Oceanside Pier, R / V Velero IV Sta. 4761-56 , coll. 08 Dec 1956, Hayward grab, 33.197°N, 117.392°W, 9.1 m, black silt, (6, LACM-AHF Poly 13298); San Diego County, off Del Mar, 1.95 miles from Del Mar Stack, R / V Velero IV Sta. 5772-58 , coll. 01 Aug 1958, Hayward grab, 32.987N, 117.291°W, 23.7 m, olive green silty sand (1, LACM-AHF Poly 13299); Orange County, off San Juan Capistrano, 0.75 miles from San Juan Capistrano Pier, R / V Velero IV Sta. 4774-56 , coll. 10 Dec. 1956, Hayward grab, 33.49°N, 117.663°W, 11.9 m, black & dark green very fine sand, oily & H 2 S (2, LACM-AHF Poly 13300); San Diego County, 0.7 miles from Cardiff by the Sea Tower, R / V Velero IV Sta. 4759-56, coll. 08 Dec 1956, Hayward grab, 33.031°N, 117.296°W, 36. 5 m, very fine green sand (16, LACM-AHF Poly 13302); Off Santa Catalina Island, 47 miles from Jewfish Point, R / V Velero IV Sta. 2122-52, coll. 19 Jun 1952, Orange peel grab, 33.318°N, 118.294°W, 87.8 m, (2, LACM-AHF Poly 13303); San Diego County, off Oceanside, 0.25 mile from Oceanside Pier, R / V Velero IV Sta. 4761- 56, coll. 08 Dec 1956, Hayward grab, 33.197°N, 117.392°W, 9.1 m, black silt, (3, LACM-AHF Poly 13304); S an Diego County, off Oceanside, 7.6 miles from Oceanside Pier, R / V Velero IV Sta. 4867-57 , coll. 20 Feb 1957, Hayward grab, 33.293° N, 117.482 W, 11.9 m (5, LACM-AHF Poly 13305).— Southern California Bight Survey, E Santa Barbara Channel, Santa Barbara County, Sta. Bight 03-4047, coll. ABC Laboratories, 24 Jul 2003, van Veen grab, 34.39548°N, 119.66218°W, 24.7 m, soft bottom (1, LACM-AHF Poly 13291); Los Angeles County, off Malibu, Nicholas Canyon Beach, Sta. Bight 03-4069, coll. City of Los Angeles Environmental Monitoring, 31 Jul 2003, van Veen grab, 34.036°N, 118.917°W, 15.5 m, soft bottom (1, LACM-AHF Poly13292); E Santa Barbara Channel, Ventura County, off Emma Wood State Beach, Sta. Bight 03-4043, coll. ABC Laboratories, 23 Jul 2003, van Veen grab, 34.284°N, 119.355°W, 18.2 m, soft bottom, (1, LACM-AHF Poly 13293); Ventura County, SE of San Miguel Island, Sta. Bight 03-4421, coll. Channel Islands National Marine Sanctuary, 21 Aug 2003, van Veen grab, 33.988°N, 120.38°W, 95 m, soft bottom, (1, LACM-AHF Poly 13294).

Description. A moderately sized species, all specimens incomplete; however one posterior fragment available. Body elongate, anterior eight segments crowded, dorsoventrally flattened, each about three times as wide as long; setiger 9 first elongate segment (Fig. 21A), becoming more cylindrical; abdominal segments 10–13 long, narrow and cylindrical in cross section; one posterior fragment with an elongate bulbous posterior end. Holotype (LACMAHF Poly 582) an 11-setiger anterior fragment, 15 mm long, 1.2 mm wide across thoracic segments; a 12-setiger anterior fragment (LACM-AHF Poly 13294) 20.1 mm long, 0.9 mm wide across setiger 4 (Fig. 21A–B); a 13- setiger anterior fragment (LACM-AHF Poly 13298) 11 mm long, 1.2 mm wide across thorax (Fig. 22A). Color in alcohol light tan; pigment entirely absent.

Pre-setiger region triangular in shape, relatively short, about as long as first two thoracic setigers (Fig. 21A). Prostomium conical, tapering to narrow rounded tip, dorsally merging posteriorly with peristomium and continuing to border of setiger 1 (Fig. 21A); eyespots absent, nuchal organs narrow slits along posterior margin. Peristomium large, ventrally entire, dorsally separated into two rings by two curved grooves from which dorsal tentacles arise (Fig. 21A); one of two dorsal tentacles attached on one specimen (Fig. 22A: LACM-AHF Poly 13298); dorsal tentacles large, thick, with prominent folds and a deep ventral groove (Fig. 22A). Ventrally, mouth from margin of prostomium, consisting of narrow vertical slit between four large lateral lobes and single ventral row of 4–5 short lobes (Fig. 22B); proboscis everted on several specimens as a short inflated lobe.

Thoracic region defined by eight short crowded setigers followed by an elongate setiger 9 about four times as long as setigers 6–8 combined (Fig. 21A). Transition from thoracic segments with defined dorsolateral setal fascicles to abdominal segments denoted by setae arising from broad cincture-like rows mostly surrounding anterior margin of each segment occurs at setiger 10 (Fig. 21A).

Branchiae or their stubs present on setigers 2–9 (Fig. 21A); most branchiae when present long, thin, rounded in cross section, tapering to rounded tip; weakly moniliform (Figs. 21A, 22A).

All parapodia of thoracic and abdominal regions biramous with setae emerging from near anterior edge of each segment; two posteriormost setigers of posterior bulbous region with only notosetae. Thoracic notopodia reduced to low inconspicuous mounds with setae arising from notch; neuropodia with a low rounded postsetal lamella on setigers 1–8 (Fig. 21B). Thoracic setigers 1–9 with dense fascicles of capillary setae in dorsolateral locations on each segment; thoracic notosetae numerous capillaries in dense fascicles consisting of five or more curved rows; neurosetae of setiger 1 with about 6–10 curved elongate and narrow acicular spines preceded by at least two rows of capillaries (Figs. 21A–B, 22A); neurosetae of setigers 2–9 numerous capillaries. Hooks of setiger 1 unidentate, weakly sigmoid, with tip sharply curving to narrow blunted tip (Figs. 21D, 22C). Abdominal setigers from setiger 10 with parapodia as low ridges bearing setae arranged in long double rows almost entirely surrounding body; with small dorsal, ventral, and lateral gaps approximating separate noto- and neuropodia; setigers 10–12 with numerous capillaries in both rows. Setiger 13 with anterior row of subuluncinate spines tapering to tapering tip, some appearing aristate (Figs. 21E, 22D); posterior row of setae with numerous capillaries. Posterior fragment with three parapodia anterior to bulbous posterior section; these parapodia possibly representing setigers 18–20 have only two rows of capillaries without any spinous setae.

Posterior region an elongate bulbous section, about 3.5 times longer than wide, distinctly set off from elongate abdominal segments (Figs. 21C, 22B); with six setigers, each with a pair of curved hooks with pointed tips (Figs. 21F–I, 22D–F); first four of these posterior setigers with noto- and neuropodial spines, last two with only notopodial spines.

Methyl Green staining. Stain concentrated dorsolaterally on peristomial rings, and laterally anterior and posterior to each set of noto- neuropodial setal fascicles from setiger 1 to at least setiger 12; branchiae and neuropodial lamellae not retaining stain.

Remarks. Heterospio catalinensis (as Longosoma) was the second species of the genus to be described after Ehlers (1874, 1875) described H. longissima and the first reported to have acicular spines in the neuropodia of setiger 1 (Hartman 1944). To date, including the present study, four species of Heterospio have been reported with neuropodial spines on setiger 1: H. catalinensis (Hartman 1944, 1957; Southern California), H. sp. A (Uebelacker 1984; Gulf of Mexico), H. alata n. sp. (South China Sea), and H. bidentata n. sp. (Coral Sea off E. Australia). Of these H. catalinensis and H. sp. A from shallow shelf depths have unidentate spines in setiger 1, whereas H. alata n. sp. and H. bidentata n. sp. have bidentate spines on setiger 1 and are both deep-water species.

Despite H. catalinensis having been described relatively early in Heterospio history by Hartman (1944), and from southern California where numerous surveys have taken place, there have been few subsequent reports of the species, apart from Hartman herself in 1957 and 1969. The reports of the species from Costa Rica by Vargas et al. (1985) and Maurer et al. (1988) did not provide any additional morphological observations. The present account, therefore, is the first to include updated morphological observations for the species in the 65 years since Hartman (1957).

Fauchald et al. (2009) referred Uebelacker’s 1984 report of Heterospio sp. A from the Gulf of Mexico to H. catalinensis; however, we disagree with this assignment. Heterospio catalinensis and H. sp. A are similar, but differ in the following respects: H. catalinensis has branchiae on setigers 2–9, low, rounded neuropodial postsetal lamellae occur on setigers 1–8, setiger 9 is the first elongate setiger, about four times as long as setiger 8, and the modified neuropodial hooks on setiger 1 are long and have a sharply curved tip; H. sp. A in contrast, has branchiae on setigers 2–6 (or 7), neuropodial postsetal lamellae are not reported, setiger 8 is the first elongate setiger and about twice as long as setiger 7, and the modified neuropodial spines of setiger 1 are hirsute with a bluntly rounded apex rather than sharply curved. Based on the present study of H. catalinensis and Uebelacker’s (1984) description of H. sp. A, both species have only capillaries on abdominal setigers 10–12 with spines first present from setiger 13. Hartman (1957) was the first to report subuluncini in H. catalinensis but did not indicate on which abdominal setigers they occurred. Here we report the presence of subuluncini on setiger 13 in H. catalinensis, while Uebelacker (1984) reported both acicular and subuluncinate spines, also from setiger 13, on H. sp. A. Given the morphological differences and disjunct geographic locations between H. catalinensis and H. sp. A, the Gulf of Mexico specimens most likely represent a separate undescribed species rather than H. catalinensis as listed by Fauchald et al. (2009).

Records of H. catalinensis from the Gulf of California in 1550–1590 m by Mendez (2006, 2007) are likely not this species because of their much greater collection depth.

Biology. Heterospio catalinensis is widely distributed offshore southern California and although the original collection reports it being dredged from bottoms with rock, brachiopods, and sponges (Hartman 1944) other more recent records from grab samples are from soft bottoms consisting of fine sands.

Distribution. Southern California, 9–104 m; Costa Rica, Gulf of Nicoya, 20– 46 m.