Semiodera inflata ( Treadwell, 1914 ) Salazar-Vallejo, 2012

Salazar-Vallejo, Sergio I., 2012, 3562, Zootaxa 3562, pp. 1-62 : 23-27

Semiodera inflata ( Treadwell, 1914) n. comb.

Figures 7, 8

Trophonia inflata Treadwell 1914:213–214 , Pl. 12, Fig. 33.

Trophonia minuta Treadwell 1914:213 , Pl. 12, Fig. 32.

Stylarioides collarifer? Moore 1923:221 .

Stylarioides dimissus Hartman, 1936:31 pro S. minuta Treadwell, 1914 .

Stylarioides inflata: Hartman 1952:71–74 , Figs 1–2 (syn., redescr.).

Pherusa inflata: Hartman 1969:297–299 , Figs 1–4; McHuron 1976:D16–D18, Fig. D4 (boring details); Hobson & Banse 1981:58, Fig. 11f; Blake 2000:15–16, Fig. 1.6.

Type material. Eastern Pacific: California. Holotype of Trophonia inflata Treadwell, 1914 ( LACM-AHF- 524 ), Catalina Island , 23–30 Jun. 1893 . Paratype of Trophonia inflata Treadwell, 1914 ( AMNH 774 ), off San Diego , 17 Jul. 1901, R.V. Elsie, haul L-1 (32°36.9' N, 117°14.7' W), 39–51 m, rocks (15 mm long, 4 mm wide, cephalic cage 12 mm long) . Holotype of Trophonia minuta Treadwell, 1914 ( LACM-AHF-522 ), damaged, La Jolla , 27 Jun. 1906, R.V. Loma, haul 1147 (32°52' N, 117°15.9' W), 18 m, sand (data from Michael & McEwen 1915:196, 199) (complete, 13 mm long, 1.5 mm wide, cephalic cage 5 mm long, 54 chaetigers) . Paratypes of Trophonia minuta Treadwell, 1914 ( AMNH 773 , one; LACM-AHF-523 , 4 damaged and tube pieces), same data as holotype .

Additional material: Eastern Pacific: California. Fifty specimens ( LACM-AHF-4861 ), Velero IV Stat. 2217 (33º42'00" N, 118º14'02" W), 1.6 km from Los Angeles Light , 22– 0.6 m, mud grab, 27 Feb. 1953; rocks and grey sand, brittle stars dominant, many worms (used to evaluate variation). Seven specimens ( LACM-AHF- 4862 ), five complete, R.V. E.W. Scripps, off Point Loma , California, 71–77 m, 19 Apr. 1938. One specimen ( LACM-AHF-4863 ), Palos Verdes Peninsula, San Pedro, R /V VELERO IV Sta. 3051-55, 2.4 miles off Point Fermin Light (288.5°T, 33°43’01” N, 118°20’14” W 33°43’00” N, 118°20’28” W), 11-12.5 fm, mud, biological dredge, 21 May 1955. Two specimens ( USNM 23264 ), off Del Monte, Monterey Bay, 9 m, 12 Aug. 1932, G.E. MacGinitie, coll. (21.5–30 mm long, 3.5–4.5 mm wide, cephalic cage 4.5 (broken)–9.0 mm long, 64–66 chaetigers; dorsal shield mostly removed). Two specimens (USNM-1191190), dried out, Pacific Grove , Jul. 1895, G.O. Snyder coll. (dorsal shield over chaetigers 1–4). One anterior fragment (USNM-43822), driedout, 11.2 km south of Cape Arago, 59–64 m, shale and coral, 21 Jul. 1939, D. Henry, coll. (anterior margin of chaetiger 1 with two lateral, large sediment tubercles). Two specimens (USNM-1191191), Point White, San Pedro, 18 May 1919, E.P. Chace, coll. One specimen (USNM-1191192), San Pedro, shore, Dec. 1924, E.P. Chace, coll. (nephridial lobes in the anterior margin of chaetiger 5); one specimen among serpulid tubes (USNM-1191193), Smuggler’s Cove , Santa Cruz Island , dredged, 30–33 m, 30 Jun. 1951, sand-rock bottom, Feder-Roberts coll. (within a tube different from serpulids) . Northwestern Mexico. Eighty specimens ( UANL), 42 complete, some without tunic, dorsals shields and chaetae broken in several specimens, Cruise BIP II, Stat. 25 (N, W), m, sandstone, 6 Oct. 1998, E. Balart & E. Amador, coll. (12.5–25.0 mm long, 2.0–3.0 mm wide, cephalic cage 8–10 mm, 52–67 chaetigers). Four specimens ( ECOSUR 1772 ), three complete, one without posterior end, Punta Las Rosas , Bahía Todos Santos, Ensenada (31º51'28" N, 116º36'21" W), 1 m depth, in Phyllospadix root-mass, 5 Mar. 2004, S.A. Salazar & SISV, coll. (10.5–17.0 mm long, 1.8–2.0 mm wide, cephalic cage 5 mm, 46–57 chaetigers) .

Description. Holotype of T. inflata (LACM-AHF-524), complete, dehydrated ( Fig. 7A); paratype incomplete posteriorly ( Fig. 7D). Body cylindrical, swollen anteriorly, tapering posteriorly; holotype 13 mm long, 4 mm wide, cephalic cage 13 mm long, 59 chaetigers; one paratype (AMNH 773) 10 mm long, 2 mm wide, cephalic cage 5 mm long, 40 chaetigers; another paratype (AMNH 774) 12 mm long, 3 mm wide, cephalic cage 12 mm long, 37 chaetigers. Tunic thin, with fine particles. Body papillae arranged in single rows with some additional, sparse larger ones; dorsal papillae larger, bottle-shaped, ventral papillae smaller, bottle-shaped or digitate.

Holotype with two palps ( Fig. 7C, only left palp remaining in AMNH 774). Other features observed in nontype specimens ( Fig. 8D). Cephalic hood short. Prostomium low cone, four large black eyes, anterior ones coalescent, posterior ones not fused. Caruncle not separating the branchiae into two lateral groups. Palps large, pale; palp keels rounded, low. Dorsal lip reduced, lateral lips larger, ventral lip reduced.

Branchiae cirriform, decreasing in size ventrally, about 16 per side, arranged in a continuous marginal row and two inner rows with smaller filaments. Nephridial lobes pale, resembling median-sized branchiae, placed below the marginal branchial row.

Cephalic cage chaetae 2.5–4.0 times as long as body width. Chaetigers 1–3 involved in the cephalic cage; chaetae arranged in transverse rows in chaetiger 1, become more lateral in chaetigers 2–3. Each chaetiger with 8–10 chaetae per bundle.

Anterior dorsal margin of first chaetiger with a projected dorsal lappet, papillated, with six cirriform papillae, two other long interramal ones; chaetiger 2 with a transverse row of larger triangular papillae, becoming very long close to notochaetal lobes. Chaetigers 1–2 of about the same size, chaetiger 3 slightly longer. Sand cemented anterior shield dorsal, mostly lost ( Fig. 7B, D, E), over chaetigers 1–5 (anteriorly projected in well preserved specimens, Fig. 8B, C). Posterior projection narrow in some specimens.

Chaetal transition from cephalic cage to body chaetae gradual; notochaetae of chaetiger 2 about 2/3 as long as those in chaetiger 1; those from chaetiger 3 half as long as those in chaetiger 2 (removed in holotype and in one paratype). Notochaetae in chaetiger 4 about one-third as long as those in chaetiger 3. Thereafter, mostly short. Neurochaetae multiarticulate capillaries in chaetigers 1–3, replaced by pseudocompound hooks from chaetiger 4, decreasing in size in chaetigers 5–6 ( Fig. 8E). Slightly falcate anchylosed neurohooks from chaetiger 7 ( Fig. 8F). Gonopodial slits in chaetiger 5 (in one paratype).

Parapodia best developed on chaetigers 1–3; subsequent ones with low chaetal lobes, with long bottle-shaped interramal papillae posteriorly. Notochaetal lobes with three small postchaetal papillae. Neuropodial lobes with three small postchaetal papillae.

Median notochaetae arranged in short transverse rows; all multiarticulate capillaries, articles long; as long as one third body width, up to 3 per fascicle in first few chaetigers and subsequent ones mainly with two per fascicle. Median neuropodia lateral, close to notopodia. Neurochaetae multiarticulate capillaries in chaetigers 1–3; in chaetigers 4–6, 1–2 pseudocompound hooks in oblique series. Falcate anchylosed neurohooks from chaetiger 7, becoming markedly falcate in median and posterior chaetigers ( Fig. 8G).

Posterior end tapering; pygidium with anus terminal, slightly projected ventrally, without anal cirri.

Variation: California. Fifty five specimens ( LACM-AHF-4861 and LACM-AHF-4862 ) were employed to evaluate the variation. Data are based on different numbers of specimens and specified with (n=), then expressed as means with observed ranges following parenthesis. For stating the length of the dorsal shield, the transverse line of papillae was regarded as the limit between each chaetiger, so if the shield was projected beyond the line, it would imply the coverage of the following chaetiger. In counting the chaetigers in the swollen anterior region, a ventral or a lateral view was used because the difference is more marked in lateral view .

LACM-AHF-4861. Trunk length (n=35) was 14.7 mm (5–28 mm). Cephalic cage length (n=49) was 4.8 mm (3–7 mm). Body width at chaetiger 10 (n=50) was 2.1 mm (1.0– 3.5 mm). The proportion between cephalic cage length and body width (n=50) was 2.4 (1.7–4.0), becoming larger for smaller organisms. Cephalic hood appearing to be made of a single ring, anterior margin papillated. The size of median notochaetae in relation to body width (n=50) was 19% (14–33%), and results were related to amount of body contraction and chaetal wear. Mean number of chaetigers (n=33) was 53 (31–64). The body was tapering in 11 specimens and swollen anteriorly in 39; and in these the swollen portion consisted of 27 chaetigers (16–32). Dorsal shield extended over 5 chaetigers (4–7 chaetigers), increasing with body size; anterior horns often eroded. The dorsal surface of the dorsal shield was rugose but without any longitudinal depression. The anterior margin of the dorsal shield is projected in an articulated plate resting on chaetiger one, which is papillated over its anterior margin. The posterior margin of the dorsal shield was rounded in 22 specimens and projected towards the following chaetigers as a semicircular low plate in another 28 specimens. Neurohooks (n=50) start in chaetiger 4 (3–4) but smaller specimens (n=7; 5–9 mm trunk length) had them from chaetiger 3, there are 2 pseudocompound or anchylosed hooks; however, simple neurohooks started always in chaetiger 7. The number of neurohooks per parapodia in chaetiger 10 (n=50) was 3 (3–4) while in chaetiger 20 was 4(3–4), in general they tend to increase by one hook in chaetigers 15–19, and their numbers increase with body size.

Pygidium had one achaetigerous segment, anus terminal or dorsoterminal; no anal cirri but sometimes anal margins were swollen. Tube calcareous, dull, inner surface rough, not polished, in sponges, calcareous rocks or consolidated sediments.

LACM-AHF-4862 (n=7). Trunk length 27 mm (19–35 mm). Cephalic cage length 12 mm (11–15 mm). Body width at chaetiger 10 4 mm (3.0– 4.5 mm). The proportion between cephalic cage length and body width was 3.4 (3–4). The size of median notochaetae in relation to body width 17%. Mean number of chaetigers 63 (57–66). The anterior swollen region includes 32 chaetigers (30–34). The dorsal shield extends over 5 chaetigers (4–5 chaetigers) being rounded in one specimen and projected posteriorly in 4 others. Pseudocompound neurohooks start in chaetiger 4 (invariable), and first simple neurohook starts in chaetiger 7 (invariable). The number of hooks per neuropodia in chaetiger 10 is 3 (3–4) and in chaetiger 20 is 5 (4–5). Thus, the dorsal shield extension expressed in number of chaetigers as well as the first start of pseudocompound or simple hooks are stable features that could be employed to separate similar species.

Other features. Anterior end observed by dissection. Branchiae sessile cirriform filaments arranged in two series dorsally, rolling laterally in two rolls; dorsal branchiae longer, becoming smaller laterally. Up to 20 branchiae per side. Prostomium with four equal-sized eyes, anterior eyes often more pigmented than posterior ones. Palp keels present, rounded. Some specimens were still in tubes; they were heterogeneous with partially broken, compacted or hard particles ( Fig. 8A) and the specimen apparently moved in it after sampling, so the inner calcareous lining was not confirmed in all cases. The tube in another specimen (LACNHM-AHF-4863) was not calcareous, but similar to Lanice , in the sense that it incorporated foraminiferans, small shell fragments and stones, but it was rather brittle instead of flexible, and with a thin inner layer, which was strong and apparently proteinaceous. Other details can be found in McHuron (1976).

Remarks. The name Trophonia minuta Treadwell, 1914 , has priority over its junior synonym T. inflata Treadwell, 1914 , by half a page. Hartman (1936:31) regarded both species as members of Stylarioides , and consequently the first species would become a junior homonym to “ Pherusa minuta de Quatrefages, 1865 ” implying that both belong in the same genus. However, de Quatrefages (1866:480–481) listed Pherusa minuta but unlike some other species, he gave no reference for this particular species, giving the impression that it was newly described but no illustrations were provided. The species had been described as Siphostoma minutum Blanchard in Gay, 1849: 36, and it has been transferred to Trophoniella Hartman, 1959 ( Salazar-Vallejo 2012b). Therefore, there is no real homonymy and Trophonia minuta Treadwell, 1914 would have priority over the more commonly employed T. inflata Treadwell, 1914 .

Further, the relationships between Trophonia and Stylarioides are treated in some detail in a review of Stylaroides ( Salazar-Vallejo 2011b) . S iphostoma and its spelling variants have been regarded as junior synonyms of Flabelligera Sars, 1829 and not of Stylarioides by Salazar-Vallejo (2012a).

Therefore, the replacement name Stylarioides dimissus Hartman, 1936 , anticipated a formal revision of the genera, and is incorrect. Berkeley & Berkeley (1941:46) regarded that Trophonia inflata should belong in Stylarioides , and Hartman (1951, 1952) agreed on this generic placement, overlooking that Støp-Bowitz (1948:13) had stated that both Stylarioides and Trophonia should be regarded as junior synonyms of Pherusa . This was later corrected by Hartman herself by introducing the combination ( Hartman 1963:56) that has been employed since. Even though it would be correct to reinstate the name P. minuta , because it has simple precedence, it would be inappropriate because that name has not been used during the last 50 years, and even if the replaced name is not so frequently employed in ecological papers, it should be conserved.

On the other hand, S. inflata ( Treadwell, 1914) n. comb., S. cinari n. sp. and S. mezianei n. sp. belong in the group of species characterised by a single series of dorsal papillae and falcate neurohooks from chaetiger 7. As stated above, S. cinari differs from the other two species because its chaetal lobes have a single papilla, or it may be absent (as opposed to having three papillae per lobe), and its median chaetigers have papillae which can be as long as ¼–⅓ the corresponding segment length. Thus, S. inflata and S. mezianei are closely allied; however, they differ because in S. inflata the papillae are shorter (¼–⅓ as long as segment length) and its chaetal lobes papillae are smaller, whereas in S. mezianei the body papillae are larger (as long as ½–⅔ segment length), and chaetal lobes have larger papillae.

Distribution. Western coast of North America, from California to northwestern Mexico, in shallow depths, boring in compact or calcareous substrates. The records from Atlantic Ocean localities require confirmation (cf. Hartman 1951, Milligan 1984).