Loimia armata, Carrerette, Orlemir & Nogueira, João Miguel De Matos, 2015

Carrerette, Orlemir & Nogueira, João Miguel De Matos, 2015, The genus Loimia Malmgren, 1866 (Annelida: Terebellidae) off the Brazilian coast, with description of three new species and notes on some morphological characters of the genus, Zootaxa 3999 (1), pp. 1-31 : 16-22

Loimia armata sp. nov.

( Figures 7–9 ; Table 3)

Loimia grubei .— Blankensteyn 1988: 62 –65, fig. 13. Loimia cf. grubei .— Alves 2008: 59 –64, figs 17–18.

Type series. Holotype MZUSP 0 2367 (coll. 21º9'5"S 40º16'13"W, 101 m, 07.Mar.2009). Paratypes 1 MZUSP 0 2368 (22º19'27"S 40º37'25"W, 73 m, 04.Jul.2009). Paratype 2 MZUSP 0 2369 (coll. 22º59'43"S 41º21'13"W, 77 m, 02.Jul.2009). Paratype 3 MZUSP 0 2370 (coll. 22º12'48"S 40º51'18"W, 52 m, 26.Feb.2009). Paratype 4 AM W.47667 (coll. 22º59'42"S 41º21'13"W, 78 m, 21.Feb.2009). Paratype 5 AM W.47668 (coll. 22º1'4"S 40º32'1"W, 49 m, 24.Jul.2009). Paratype 6 USNM 1273438 (coll. 22º37'27"S 41º21'57"W, 53 m, 27.Feb.2009). Paratype 7 USNM 1273439 (coll. 22º37'30"S 41º21'57"W, 53 m, 27.Feb.2009). Paratypes 8 MZUSP 0 2371 (coll. 22º17'21"S 40º6'42"W, 143 m, 17.Aug.2009): paratype 9 ZUEC 16677 (coll. 22º7'38"S 40º18'52"W, 73 m, 24.Feb.2009), paratype 10 ZUEC 16678 (coll. 22º37'27"S 41º21'57"W, 53 m, 27.Feb.2009).

Material examined. Project HABITATS/PETROBRAS: State of Rio de Janeiro—Campos Basin, mouth of Rio Paraíba do Sul— 21º10'11"S 40º46'4"W, 21 m, 1 spec., 22.Jul.2009; 22º1'4"S 40º32'1"W, 49 m, 1 spec., 24.Jul.2009; 21º57'11"S 40º38'5"W, 26 m, 1 spec., 26.Feb.2009; 21º49'50"S 40º44'40"W, 28 m, 1 spec., 25.Feb.2009; 22º45'44"S 41º45'39"W, 53 m, 1 spec., 16.Jul.2009; 22º45'44"S 41º45'39"W, 53 m, 2 specs, 16.Jul.2009; 22º45'44"S 41º45'39"W, 53 m, 5 specs, 16.Jul.2009; 22º37'27"S 41º21'58"W, 54 m, 1 spec., 16.Jul.2009; 22º7'38"S 40º18'52"W, 73 m, 2 specs, 24.Feb.2009; 22º59'42"S 41º21'13"W, 77 m, 1 spec., 21.Feb.2009; 22º59'42"S 41º21'13"W, 78 m, 1 spec., 21.Feb.2009; 23º1'42"S 41º58'34"W, 80 m, 2 specs, 16.Mar.2009; 22º17'37"S 40º27'6"W, 103 m, 2 specs, 04.Jul.2009; 22º23'17"S 40º35'3"W, 110 m, 1 spec., 25.Jul.2009. Project BIOTA-FAPESP, Bentos Marinho –Ubatuba: 23º25'S 44º46'W, 35 m, 1 spec., 17.Mar.2001; 23º23'S 44º50'W, 15.2 m, 1 spec., 17.Mar.2001; 23º31'S 5º07'W, 11.2 m, 1 spec., 23.Mar.2002; 23º32'S 45º09'W, 10.3 m, 2 specs, 14.Apr.2002. São Sebastião: 23º41'S 45º16'W, 15.4 m, 2 specs, 13.Feb.2001; 23º58'S 45º31'W, 33.6 m, 2 specs, 27.Jun.2002.

Additional material examined for comparison. Loimia grubei sensu Blankensteyn (1988) — ZUEC 6131 (coll. 24°53'00"S 46°46'07"W, 47 m, 1 spec.); ZUEC 6043 (coll. 24°16'00"S 46°01'02"W, 50 m, 1 spec.). L. medusa sensu Blankensteyn (1988) — ZUEC 6044 (coll. 26°29'05"S 48°21'04"W, 38 m, 1 spec.). Loimia bandera Hutchings, 1990 : holotype, AM W.201924 (coll. 6 km S.S.E off Port Island, New Territories, 24 m, S/edge, coll. 5.Apr.1986); paratypes AM W.201926–7 (coll. Hong Kong, Tap Mun, 22°29'N 114°22'E, Apr.1986). Loimia batilla Hutchings & Glasby, 1988 : holotype, AM W.5162 (coll. Moreton Bay, 20°26'S 147°05'E, Queensland, Australia, coll. 1971); paratype AM W.7097 (coll. Middle Banks off Tangalooma, 27°12'S 153°21'E, Queensland, Australia, coll. 1972); paratype AM W.7106 (coll. Middle Banks off Tangalooma, 27°12'S 153°21'E, Queensland, Australia, coll. 1972); paratype AM W.7107 (coll. Moreton Bay, 20°26'S 147°05'E, Queensland, Australia, coll. 1970). Loimia triloba Hutchings & Glasby, 1988 : paratype AM W. 200558 (coll. Australia, Queensland, Low Isles, Great Barrier Reef, 16°23'S 145°34'E). Loimia medusa (Savigny in Lamark, 1818): neotype, LACM-AHF Poly 1656 (coll. Upper Persian Gulf, coll. Tetra Tech, Apr.1982, shallow shelf).

Description. Stout, anteriorly expanded then cylindrical ( Figs 7 A–H; 9A–D), chaetigers progressively longer on segments 12–20. Complete specimens with 93–95 (93) segments, 34–40.2 (40.2) mm long, 3.2–3.5 (3.2) mm wide (Table 3). Preserved body whitish, without distinct patterns of pigmentation ( Fig. 7 A–H). Prostomium at base of dorsal side of upper lip, basal part without eyespots, distal part as V-shaped crest ( Fig. 7 A–C, F–G), buccal tentacles distinctly short, not reaching beyond chaetigers 1–2 (segments 4–5), if directed posteriorly. Peristomium restricted to lips; relatively short, nearly circular upper lip, projecting anteriorly ( Figs 7 A–G; 9A–C); lower lip short, button-like to rectangular, almost completely covered by membrane connecting lobes of segment 1 ( Fig. 9 A– C). Segment 1 visible entirely, dorsally short, with large paired lobes, originating abruptly, ventro-laterally, with straight dorsal margin aligned with dorsal edge of neuropodia; lobes high, distally straight, almost reaching tip of upper lip ( Figs 7 A–G; 9A–C). Segment 2 dorsally and laterally short, hidden by lobes of segment 3, fused to segment 3 ventrally ( Figs 7 A–G; 9A–C); segment 3 longer than previous segments, with large paired lobes nearly of same size as those of segment 1; lobes high, distally rounded, covering at least basal halves of lobes of segment 1; oblique lobes, with wide base, originating laterally along entire extension of segment 3, from anterior to posterior margins of segment, dorsal edges aligned to base of notopodia of segment 4, terminating ventrally at each superior corner of partially fused mid-ventral shield of segments 2–4 ( Figs 7 A, D–G; 9A–C); dorsal margins of lobes pointed, tip extending dorsally in relation to base, reaching bases of branchiae ( Figs 7 A, E–G; 9A–C); segment 4 conspicuous all around, partially fused to segments 2–3 mid-ventrally in single mid-ventral shield, lobes absent; following segments all about same size. Three pairs of branching branchiae on segments 2–4, with long basal stem, first pair vertically aligned to following pairs ( Fig. 7 B–C). Smooth to slightly crenulate mid-ventral shields on segments 2–12, partially fused on segments 2–4; rectangular shields, those from segments 2–5 wider, then all about same size until segment 11, last shield narrower than preceding ones, swollen and divided in two parts by transverse line at mid-length; after segment 12 shields replaced by mid-ventral groove extending posteriorly ( Figs 7 A, D–G; 9A–B). Cylindrical, short notopodia, on segments 4–20, bearing narrowly-winged chaetae in both rows, those from posterior row longer, with wings along most extension of chaetae, except for basal third ( Figs 8 A–D; 9F–G). Neuropodia beginning from segment 5, as low rectangular ridges slightly raised from surface of body until segment on which notopodia terminate, thereafter as elongate, prominent pinnules ( Figs 7 A, D–G; 9A–B, D); neuropodia bearing uncini in double rows on segments 11–20, tori aligned ventro-laterally from segment 5 to termination of notopodia, uncini in crest to crest arrangement, rows almost completely separate, only uncinial crests intercalating sometimes ( Figs 8 F–G; 9E). Uncini pectinate, higher than long, with concave base, short and triangular heel directed backwards, rounded prow downwardly directed, prow connected to long ligament ( Fig. 8 E–J); on segments 5–10, uncini with 5–6 teeth, teeth progressively shorter upwards, basal tooth distinctly stouter than following teeth, aligned with the prow; from segment 11, uncini with 6–7 teeth; after notopodia terminate, uncini with up to 8 teeth, frequently varying within torus ( Figs 8 E–J; 9E, H–I). Genital papillae posterior to base of notopodia of segments 6–8 ( Figs 7 A, E–G; 9A); some mature specimens with gametes visible through body wall between the anterior notopodia. Pygidial papillae not observed.

Remarks. Five other species of Loimia share with L. armata sp. nov., the presence of mid-ventral shields until segment 12, L. bandera , L. batilla , L. bermudensis , L. medusa , and L. megaoculata . Of these, L. bandera , L. batilla , L. medusa and L. megaoculata have the number of uncinial teeth similar to L. armata sp. nov. (see Table 2), however none of them have either uncini with more than 6 teeth, as those of posterior segments of L. armata sp. nov., or, except for L. megaoculata , variation on the number of uncinial teeth within tori, as occurs in L. armata sp. nov. As described above, L. megaoculata differs from L. armata sp. nov., in the morphology of the lobes of the anterior segments and in having large eyespots at the base of prostomium.

In addition to similar number of ventral shields, L. bandera shares with L. armata sp. nov., a similar V-shaped structure of the distal part of prostomium and the presence of genital papillae on segments 6–8. On the other hand, L. bandera differs from L. armata sp. nov., in having shorter uncinial teeth, with little difference in size along the row, while in L. armata sp. nov., uncinial teeth are longer and they vary in size along the row. In addition, the lobes of segment 1 of L. bandera originate dorso-laterally, at level of first pair of branchiae, while in L. armata sp. nov., TABLE 3. Morphological variation within the type-series of Loimia armata sp. nov.

Holotype Paratype 1 Paratype 2 Paratype 3 Paratype 4 Paratype 5 Paratype 6 Paratype 7 Paratype 8 Paratype 9 Paratype 10 (MZUSP (MZUSP (MZUSP (MZUSP (AM (AM (USMN (USNM (MZUSP (ZUEC (ZUEC 02367) 02368) 02369) 02370) W.47667) W.47668) 1273438) 1273439) 02371) 16677) 16678)

(length x 40.2 x 3.2 20.1 x 3.2 20.3 x 3.0 20.2 x 3.2 19.2 x 2.9 9.0 x 0.5 27.0 x 3.1 18 x 2.2 18 x 3.0 10.3 x 2.1 34 x 3.5 width (mm))

Number of Two 29 segments 39 33 32 45 41 40 22 18 95 segments fragments:1st

– 33 segs; 2nd

– 60 segs

Ventral 12 12 12 12 12 12 12 12 12 12 12 shields

segments)

Genital Not visible; Not visible; 6–8 Not visible; Not visible; Not visible Not visible Not visible 6–8 Not visible; Not visible; papillae anterior anterior anterior anterior anterior anterior

segments) segments segments segments segments segments with segments with mass of with mass of with mass of with mass of mass of with mass of gametes gametes gametes gametes gametes gametes

Number of 5– 6 x 6–8 5– 6 x 7 6 x 7–8 6 x 6–7 6 x 6–8 5– 6 x 7 5– 6 x 7 5– 6 x 7 6 x 7–8 5– 6 x 6–8 6 x 6–7 teeth: anterior

posterior

uncini

the lobes of segment 1 are only ventral, beginning at the level of the dorsal edge of neuropodia. Loimi batilla is very similar to L. bandera , in all characters discussed above, thus it also differs from L. armata sp. nov., in the same features (see Table 2).

Loimia medusa differs from L. armata sp. nov., in having eyespots present laterally at basal part of prostomium, and uncini with 4–5 teeth ( Fig. 2 C, G–H), while in L. armata sp. nov., eyespots are absent and the uncini have 5–8 teeth, depending on body region (Tables 2 and 3). In addition, L. medusa has lobes of segment 1 originating dorso-laterally, aligned with the notopodia of segment 4 ( Fig. 1 D, J), with oblique dorsal edges and distally rounded, only reaching around half length of the upper lip ( Fig. 1 D); and lobes of segment 3 rounded, with narrow base, extending from ventral to dorsal edges of neuropodia, separate from fused mid-ventral shield of segments 2–3, and also with expanded dorsal edge distally, reaching beyond bases of branchiae of segment 3 ( Fig.

1D, J). On the other hand, L. armata sp. nov., has lobes originating ventro-laterally, with straight dorsal margin aligned with dorsal edge of neuropodia, lobes high, distally straight, almost reaching tip of upper lip ( Figs 7 A–G; 9A–C); segment 3 with lobes of nearly the same size as those of segment 1, larger than those of L. medusa , and oblique, originating from both anterior and posterior margins of segment 3, aligned to bases of notopodia of segment 4, terminating ventrally at each superior corner of partially fused mid-ventral shield of segments 2–4.

Loimia grubei was recorded for the Brazilian coast by Blankensteyn (1988) and Alves (2008), however we believe these records may be misidentifications, considering the distance between Brazil and the type locality, which is Philippines. Attempts to locate the type material or material from the type locality were unsuccessful. This species was originally described as Terebella montagui by Grube (1878) and was posteriorly transferred to L. grubei by Holthe (1986a), replacing Terebella montagui Grube, 1878 , primary homonym of Terebella montagui Quatrefages, 1865 , and secondary homonym in combination with Loimia by Hartman (1959) ( Holthe 1986a). Since Holthe (1986a) did not include a description of this species, we used for comparison with L. armata sp. nov., the brief description given by Hartman (1959), as L. montagui (Table 2). According to Hartman (1959), the species has paired, rounded lateral lobes on segment 1, lobes of segment 3 slightly shorter and distally rounded, mid-ventral shields extending to segment 14, and uncini with 5–6 teeth. In contrast, L. armata sp. nov., has large ventro-lateral lobes on segment 1, with straight dorsal margins, nearly rectangular, segment 3 with pair of well developed lobes, nearly the same size as those present on segment 1, mid-ventral shields on segments 2–12, and uncini with 5–8 teeth.

After examination of the material studied by Blankensteyn (1988) and Alves (2008), we attribute these records of Loimia grubei and L. cf. grubei for the Brazilian coast to L. armata sp. nov., just described.

Etymology: We attribute the epithet “ armata ” to this taxon in reference to the large lobes on segment 1, directed anteriorly and encasing the mouth, as a shield or a helmet.

Type locality and distribution: States of Rio de Janeiro (Campos Basin) and São Paulo.

Figures

FIGURE 1. Loimia batilla (Holotype, AM W. 5162): (A). Anterior part, ventral view; (I). Anterior part, lateral view. L. triloba (Paratype, AM W. 200558): (B). Anterior part, ventral view; (G). Anterior part, dorsal view. L. bandera (Holotype, AM W. 201924): (C). Anterior part, ventral view; (F). Anterior part, dorsal view. L. medusa (Neotype, LACM-AHF Poly 1656): (D). Anterior part, ventral view; (J). Anterior part, lateral view. L. armata sp. nov. (Paratype, MZUSP 02368): (E). Anterior part, ventral view; (H). Anterior part, ventro-lateral view. Numbers refer to the segments; P = Prostomium; ul = upper lip. Scale bars: A – B = 1 mm; C – G = 500 µm; H – J = 400 µm.

FIGURE 2. Loimia bandera (Paratype, AM W. 201927): (A). Anterior uncini, segment 5; (E). Uncini of the segment 11; (H). Posterior uncini, segment 25. L. batilla (Paratype, AM W. 7100): (B). Anterior uncini, segment 5; (I). Posterior uncini, segment 25. L. medusa (Neotype, LACM-AHF Poly 1656): (C). Anterior uncini, segment 5; (G). Uncini of the segment 11; (J). Posterior uncini, segment 25. L. triloba (Paratype, AM W. 200558): (D). Anterior uncini, segment 5; (F). Uncini of the segment 11; (K). Posterior uncini, segment 25; (L). Posterior uncini, segment 34. Scale bars: A, C – D, G = 50 µm; B = 30 µm; E = 3 µm; F = 5 µm; H – L = 20 µm.

FIGURE 7. Loimia armata sp. nov. (Holotype, MZUSP 02367): (A). Anterior part, ventral view; (B). Anterior part, dorsal view; (C). Detail of anterior part, dorsal view; (D). Detail of anterior part, lobes on anterior segments, ventral view; (E – F). Anterior part, left ventro-lateral view; (G). Anterior part, right ventro-lateral view. Numbers refer to segments; II = lower lip; P = prostomium; ul = upper lip. Scale bars: A = 200 µm; B – C = 400 µm; D – G = 500 µm.

FIGURE 8. Loimia armata sp. nov. (Holotype, MZUSP 02367): (A). Notochaetae from segment 5; (B). Notochaetae from segment 8; (C). Notochaetae from segment 15; (D). Notochaetae from segment 19; (E). Uncini from segment 7; (F). Uncini from segment 18; (G). Uncini from segment 19; (H). Uncini from segment 31; (I). Uncini from segment 26; (J). Uncini from segment 35. Scale bars: A – D = 20 µm; E – I = 20 µm; J = 5 µm.

FIGURE 9. Loimia armata sp. nov. (Paratype, MZUSP 02371): (A). Anterior part, ventral view; (B). Detail of the anterior part, ventral view; (C). Detail of the anterior part, lobes on segments 1 and 3, lateral view; (D). Detail of the transition, between region with biramous parapodia and only with neuropodia; arrows point to anterior (white) and posterior (black) tori; (E). Uncini from the anterior part, double rows of uncini; (F). Notopodium from the anterior part; (G). Detail of the notochaetae from anterior part; (H). Uncini from segment 24; (I). Detail of uncini from anterior segment, segment 14. Numbers refer to segments; II = lower lip; P = prostomium; ul = upper lip. Scale bars: A = 300 µm; B – C = 200 µm; D = 100 µm; E, G – I = 5 µm F = 50 µm.