Meiodorvillea hartmanae, Bonaldo & Steiner & Amaral, 2022

Bonaldo, Rafael de Oliveira, Steiner, Tatiana Menchini & Amaral, Antônia Cecília Zacagnini, 2022, Revision of Meiodorvillea Jumars, 1974 (Annelida: Dorvilleidae) including descriptions of three new species from the Southwestern Atlantic Ocean, PLoS ONE (e 0264081) 1974 (3), pp. 1-27 : 17-21

publication ID	https://doi.org/ 10.1371/journal.pone.0264081
DOI	https://doi.org/10.5281/zenodo.12630857
persistent identifier	https://treatment.plazi.org/id/039F6D46-2C7F-FFEF-4111-771BFA7A223A
treatment provided by	Felipe
scientific name	Meiodorvillea hartmanae
status	sp. nov.

Treatment

Meiodorvillea hartmanae View in CoL sp. nov.

( Figs 13–17 View Fig 13 View Fig 14 View Fig 15 View Fig 16 View Fig 17 , Table 1 View Table 1 )

urn:lsid:zoobank.org:act:9DC54BE0-27ED-44E2-AD4D-2CB22E05D830

Type locality. Southwest Atlantic Ocean , 23˚15’11,480"S, 40˚53’53,304"W, off Rio de Janeiro State, Brazil, 1,228.5 m depth.

Type material examined. Holotype: State of Rio de Janeiro – ZUEC-POL 21406 23˚ 15’11.480"S 40˚53’53.304"W, 1,228.5 m, 14 Jan 2009 GoogleMaps . Paratypes: State of Rio de Janeiro – ZUEC-POL 21407 (2 spec) 23˚15’10.577"S 40˚53’54.586"W, 1,300.7 m, 15 Jan 2009 GoogleMaps ; ZUEC-POL 21408 (1 spec) 23˚13’46.474"S 40˚55’56.178"W, 986.4 m, 08 May 2008 GoogleMaps ; ZUEC-POL 21409 (1 spec) 23˚13’48.724"S 40˚55’53.562"W, 1,001.4 m, 16 Jan 2009 ; ZUEC-POL 21410 (1 spec) 23˚13’47.452"S 40˚55’56.256"W, 986.4 m, 08 May 2008 GoogleMaps ; ZUEC-POL 21411 (2 spec) 23˚ 13’48.742"S 40˚55’55.134"W, 986.4 m, 08 May 2008 GoogleMaps ; ZUEC-POL 21412 (1 spec) 23˚41’9.142"S 41˚16’7.032"W, 1,001.5 m, 13 Jan 2009 GoogleMaps . (m = meters depth).

Other material examined. State of Rio de Janeiro – ZUEC-POL 21413 (1 spec) 21˚ 45’54.702"S 39˚59’27.418"W, 1,030 m, 06 Feb 2009; ZUEC-POL 21414 (1 spec) 23˚13’48.868"S 40˚55’54.397"W, 1,010.8 m, 16 Jan 2009; ZUEC-POL 21415 (1 spec) 23˚15’11.480"S 40˚ 53’53.304"W, 1,228.5 m, 14 Jan 2009; ZUEC-POL 21416 (1 spec) 21˚55’7.018"S 39˚ 54’31.298"W, 996.9 m, 07 Feb 2009. State of Espírito Santo – ZUEC-POL 21417 (1 spec) 21˚ 4’37.64"S 40˚8’32.68"W, 1,015 m, mud, 08 Jun 2013; ZUEC-POL 21418 (1 spec) 20˚15’36.86"S 39˚46’15.05"W, 1,040 m, sandy mud, 09 Jan 2012. (m = meters depth).

SEM material. State of Rio de Janeiro – ZUEC-POL 21419 (3 spec): 23˚1’30.862"S 40˚ 45’22.948"W, 964.8 m, 16 Jan 2009; 21˚55’6.677"S 39˚54’32.810"W, 997 m, 28 May 2008; 23˚ 13’48.868"S 40˚55’54.397"W, 1,010.8, 16 Jan 2009 (m = meters depth).

Diagnosis. One pair of antennae and one pair of palps. Dorsal cirri absent. Ventral cirrus papilliform, absent in the first chaetiger. Chaetae capillary, furcate asymmetrical, dorsalmost compound spiniger or falciger, median and ventralmost falcigers, and cultriform in last chaetigers in some specimens, replacing the ventralmost compound. Two pairs of pygidial cirri.

Description of the holotype. Complete specimen, 37 chaetigers, 1.9 mm long, anterior region 0.17 mm wide, excluding parapodia; body width uniform ( Fig 13A View Fig 13 ), anterior region slightly wider. Color in ethanol pale yellow.

Prostomium pear-shaped, as long as wide, anterior half depressed and rounded, posterior half wider and globular ( Figs 13A, 13B View Fig 13 and 14A–14C View Fig 14 ). Eyes absent. One pair of clavate antennae inserted dorsolaterally on middle posterior half of prostomium, 1/3 of prostomium length ( Figs 13B, 13C View Fig 13 and 14A–14C View Fig 14 ). One pair of very small and clavate palps inserted laterally at prostomium base, difficult to see in dorsal view ( Figs 13C View Fig 13 and 14C View Fig 14 ).

Two peristomial rings, half as long as prostomium, posterior wider than anterior ( Figs 13B View Fig 13 and 14 View Fig 14 A-14C).

Cylindrical, long and stout parapodia, gradually tapering posteriorly ( Fig 15 View Fig 15 ). Dorsal cirrus absent. Small and papilliform ventral cirrus, inserted medially in the parapodium ( Fig 15 View Fig 15 ), absent in the first one.

Supra-acicular chaetae: (1) one long and serrated capillary; (2) one elongated and thin furcate, asymmetrical prongs in shape and size and serrated base ( Fig 16A–16D View Fig 16 ). Sub-acicular chaetae: (3) three compound heterogomphs, dorsalmost longest with falcigerous or spinigerous blade, median falcigerous, ventralmost falcigerous and shortest; blades unidentate with serrated cutting edge ( Fig 16E–16G View Fig 16 ); (4) one cultriform with serrated margin replacing the ventralmost compound in last chaetigers ( Fig 16H View Fig 16 ). Chaetae gradually slender and longer along body. One internal thick acicula ( Fig 15B and 15D View Fig 15 ).

Pygidium rounded and narrower than previous chaetigers. Two pairs of clavate pygidial cirri, dorsal pair twice as long as ventral pair ( Figs 13E View Fig 13 , 14D and 14E View Fig 14 ).

Jaw apparatus from additional non-type material with ventral and medially fused mandibles, anterior region enlarged with smooth margins without free or fused teeth, posterior region slender and curved ( Fig 17A View Fig 17 ). Basal plates of maxillae with smooth inner margin, two subsymmetrical rows with 10–12 pairs of free rectangular and denticulate maxillary plates, each one with one posterior main fang and usually four anterior teeth last and anteriormost plates larger and rounded, with small and more numerous teeth. ( Fig 17A–17C View Fig 17 ).

Variation. Complete specimens 1.5–2.9 mm long, maximum width 0.28 mm, 28–48 chaetigers; some with posterior moniliform segments (width equal to length). Palps visible only ventrally in some specimens. Most specimens with cultriform chaetae, with serrated cutting edge, in last 9–13 chaetigers, or randomly ( Fig 16H View Fig 16 ). Maxillary plates varying from 10 to 13 pairs.

Remarks. Meiodorvillea hartmanae sp. nov. resembles M. apalpata and M. penhae in having papilliform ventral cirrus in all parapodia (except the 1 st), but differs having furcate and lacking geniculate chaetae. On the other hand, M. minuta differs in having dorsal cirri on anterior chaetigers and a different shape of furcate.

Meiodorvillea hartmanae sp. nov. has smaller palps than all other species of the genus. In some specimens the palps are very difficult to see in dorsal view; in others, only ventrally. The species also has remnants of ciliary bands in the prostomium, peristomium, and chaetigers, as M. penhae and M. minuta . This character may possibly be shared by all species of Meiodorvillea .

Geographic distribution and bathymetric range. Southwestern Atlantic Ocean, States of Espírito Santo and Rio de Janeiro ( Brazil), 964.8 to 1,300.7 m; mud, muddy sand, sandy mud. Etymology. The specific epithet “ hartmanae ” honors Olga Hartman for her insight contributions to the taxonomy of Polychaeta and for describing the type species of Meiodorvillea .