Loimia minuta Treadwell, 1929

Londoño-Mesa, Mario H., 2009, Terebellidae (Polychaeta: Terebellida) from the Grand Caribbean region 2320, Zootaxa 2320 (1), pp. 1-93: 39

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http://doi.org/ 10.11646/zootaxa.2320.1.1



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Loimia minuta Treadwell, 1929


Loimia minuta Treadwell, 1929  

Figures 10 View FIGURE 10 A-J

Loimia minuta, Treadwell, 1929:10–11   , Figs 28–30.— Londoño-Mesa & Carrera-Parra, 2005:21–22 View Cited Treatment , Figs 5 View FIGURE 5 H-N, reinstated.

Type material: Holotype AMNH 1992 View Materials (1) Dry Tortugas, Florida, 1910.  

Additional material: Mexican Caribbean   : Quintana Roo State: ECOSUR TERE-11 E2 (1) Leeward of Contoy Island (21°30'8.4"N 86°47'45.3"W), X.1983 GoogleMaps   , by trawling. TERE-11 (1) Majahual (18°40'9.6"N 87°43'1.4"W), 22.III.2000 GoogleMaps   . TERE-11 (1) Paraiso Beach, Cozumel Island , 5.VI.1995   . TERE-11 (1) Leeward of Contoy Island (21°30'8.4"N 86°47'45.3"W), 3.III.2001; 2m. GoogleMaps  

Diagnosis: Holotype incomplete, with 43 segments, 11mm long, thorax 7mm long, 2.5mm wide ( Figs 10 View FIGURE 10 A-C). Body brown. Abdomen thinner than thorax, with visible segmentation. Tentacular membrane short, narrow, rounded edge visible on ventral side; eyespots absent; tentacles missing. Upper lip short, narrow, semi-circular, projecting forwards ( Fig. 10D View FIGURE 10 ). Lower lip short, swollen and somewhat hidden by segment 1 ( Fig. 10E View FIGURE 10 ). First pair of lateral lappets projecting forwards, laterally surrounding tentacular membrane, and lower lip ventrally; second pair with short base, not connected to ventral shield, and with dorsal edge slightly developed, not covering base of branchiae. Sixteen ventral shields from segment 2; first three shields shorter and wider; next 9 shields swollen but decreasing in size posteriorly; last 4 shields divided transversally in two parts; abdomen with mid-ventral longitudinal groove. Nephridial papillae not seen. Notopodial glandular tissue absent. Branchiae branched, spiralled, slightly decreasing in length posteriorly; branchiae on dorsal left side and second right one absent. Notochaetae of two lengths, asymmetrically bilimbate, pointed; chaetae with some longitudinal striations ( Fig. 10G View FIGURE 10 ). Neuropodia with uncini avicular, with five aligned teeth; uncini from segment 5–10 ( Fig. 10H View FIGURE 10 ) PP developed, angular; PF absent; Oc long, concave; Cp with 1 vertical row of five teeth, decreasing in size in proportions of 3/4 the above; USr concave; SrP well-developed, rounded and directed anteriorly; LSr concave; AP with AF thin, projected downward; Bs slightly concave. Uncini from segments 11–20 ( Fig. 10I View FIGURE 10 ) with four aligned teeth; abdominal uncini smaller, with five aligned teeth, distal tooth small ( Fig. 10J View FIGURE 10 ). Abdominal neuropodia well developed, as swollen lappets with short rows of uncini, straight or semi-curved. Pygidium missing.

Staining pattern: Lateral lappets, first four segments, dorsally, and notopodia, also dorsally, stain deeply. Small longitudinal lateral bands to last two ventral shields and ventral gap between thoracic neuropodia stain lightly. Ventral shields and rest of structures remain pale.

Variation: Complete specimens from the Mexican Caribbean   have 102–105 segments, 62mm long, thorax 13mm long and 3mm wide, tentacles small, smooth, posterior ventral shields trisected, and pygidium with 6 long digitate papillae.

Discussion: This species was synonymized with Loimia medusa   (Savigny in Lamarck, 1822) by Fauvel (1914) because of the then current belief in wide (cosmopolitan) distribution of L. medusa   in warm seas. Hartman (1956) followed this concept since the species apparently matched with Savigny’s description. Nevertheless, some important differences were also found in the uncini of the present material, additional to those presented by Hutchings & Glasby (1995); L. minuta   has anterior thoracic uncini with 5 teeth, posterior thoracic uncini with 4 teeth and abdominal uncini with 5 teeth, all uncini with thin AF in this species, while L. medusa   has posterior thoracic uncini and abdominal ones with 4 teeth. On the other hand, L. bermudensis   is a similar species too, but it differs from L. minuta   in having all uncini with 5 teeth. Thus, according to this character, it is a distinct species and should be regarded as valid.

Type locality: Dry Tortugas, Florida. Intertidal   .

Distribution: Florida to the Mexican Caribbean   coast.


El Colegio de la Frontera Sur (Mexico)














Loimia minuta Treadwell, 1929

Londoño-Mesa, Mario H. 2009

Loimia minuta, Treadwell, 1929:10–11

Londono-Mesa, M. H. & Carrera-Parra, L. F. 2005: 21
Treadwell, A. L. 1929: 11