Marphysa birgeri, Molina-Acevedo & Idris, 2020

Molina-Acevedo, Isabel C. & Idris, Izwandy, 2020, Reinstatement of species belonging Marphysa sanguinea complex (Annelida Eunicidae) and description of new species from the mid-Pacific Ocean and the Adriatic Sea, Zootaxa 4816 (1), pp. 1-48 : 10-12

publication ID	https://doi.org/ 10.11646/zootaxa.4816.1.1
publication LSID	lsid:zoobank.org:pub:0475E09C-792F-4F55-9F1F-C85B8A6E44AD
persistent identifier	https://treatment.plazi.org/id/E3069005-FFAD-FFDB-46D6-FF7B7D75F8A9
treatment provided by	Plazi
scientific name	Marphysa birgeri
status	sp. nov.

Treatment

Marphysa birgeri View in CoL n. sp.

Figures 3 View FIGURE 3 , 9C View FIGURE 9 , Table 1

Eunice sanguinea . — Grube 1864: 79 (non Montagu, 1813)

Material examined. Type material: Holotype ZMB F.2021 and four Paratypes ZMB 12273, Trieste and Cres Island , Adriatic Sea, Mediterranean Sea, coll. A.E. Grube.

Additional material: ZMBQ.2265 (1 specimen), Lussingrande , Croatia, Adriatic Sea , Mediterranean Sea, August, or September 1861, coll. A.E. Grube. ZMB 7596 View Materials (1 specimen), Rovinj, Croatia, Adriatic Sea, Mediterranean Sea, coll. S. Heider.

Description. Holotype complete, with 113 chaetigers, L10 = 5.7 mm, W10 = 2.5 mm TL = 43 mm. Anterior region of the body with dorsum convex and flat ventrum; body depressed from chaetiger 10, widest at chaetiger 15, tapering after chaetiger 44.

Prostomium bilobed, 1 mm long, 1.6 mm wide; lobes frontally rounded; median sulcus shallow anteriorly and deep ventrally ( Fig. 3 View FIGURE 3 A–B). Prostomial appendages in a semicircle, median antenna isolated by a gap. Palps reaching middle of second peristomial ring; lateral antennae reaching first chaetiger; median antenna reaching middle of first chaetiger. Palpophores and ceratophores ring-shaped, short, slender; palpostyles and ceratostyles tapering, slender. Eyes ovate, brown, between palps, and lateral antennae.

Peristomium (1.2 mm long, 2.3 mm wide) larger and wider than prostomium, first ring two times longer than second ring, separation between rings distinct on all sides ( Fig. 3 View FIGURE 3 A–C). Ventral lip with a slight central anterior depression, with a pair of shallow wrinkles ( Fig. 3B View FIGURE 3 ).

Maxillary apparatus with MF = 1 + 1, 3 + 4, 5 + 0, 4 + 7, 1 + 1 ( Fig. 3D View FIGURE 3 ). MI 3 times longer than length of Maxillary carriers. MI forceps-like, MI 4.3 times longer than length of closing system ( Fig. 3D View FIGURE 3 ); ligament between MI and MII, strongly sclerotized. MII with recurved triangular teeth; MII 3.6 times longer than length of cavity opening ( Fig. 3D View FIGURE 3 ); ligament between MII and MIII and right MIV, sclerotized. MIII with triangular teeth; with irregular attachment lamella, situated in center of the right edge of the plate, slightly sclerotized ( Fig. 3D View FIGURE 3 ). Left MIV with two lateral teeth larger than rest; attachment lamella rectangular, wide, better developed in right side, situated along anterior edge of maxilla, sclerotized. Right MIV with three lateral teeth larger than rest; attachment lamella semicircle, wide, better developed in right side, situated 2/3 along anterior edge of maxilla, sclerotized ( Fig. 3D View FIGURE 3 ). MV square, with a short, rounded tooth. Mandibles amber; calcareous cutting plates absent, sclerotized cutting plates amber, with 14 growth rings ( Fig. 3E View FIGURE 3 ).

Pectinate branchiae with up to two long filaments, present from chaetigers 17L–18R to 97 ( Fig. 3I View FIGURE 3 ). One filament in chaetigers 17L to 41L; two filaments in chaetigers 42L to 75L; one filament in chaetigers 76L to 97L ( Fig. 9C View FIGURE 9 ). Branchial filaments longer than dorsal cirri except in first three chaetigers.

First three parapodia smaller, best developed in chaetigers 4–26, following ones becoming gradually smaller. Dorsal cirri digitiform in first chaetigers, conical in median-posterior ones; longer than ventral cirri in all chaetigers; best developed in chaetigers 2–16, following ones smaller ( Fig. 3 View FIGURE 3 F–J). Prechaetal lobes short, as transverse folds in all chaetigers ( Fig. 3 View FIGURE 3 F–J). Chaetal lobes rounded in first 25 chaetigers, shorter than postchaetal lobe, with aciculae emerging dorsal to midline; from chaetiger 26 triangular, longer than other lobes, with acicula emerging in midline ( Fig. 3 View FIGURE 3 F–J). Postchaetal lobes well developed in the first 32 chaetigers; digitiform in the first five chaetigers, ovoid in chaetigers 6 to 10, rounded from chaetiger 11, progressively smaller from chaetiger 10; from chaetiger 33 inconspicuous ( Fig. 3 View FIGURE 3 F–J). Ventral cirri digitiform in the first five chaetigers; from chaetigers 6 to 68 with an oval swollen base and digitiform tip; digitiform from chaetiger 69, gradually reducing in size ( Fig. 3 View FIGURE 3 F–J).

Aciculae blunt, reddish along most of its length, and amber on the distal tip ( Fig. 3 View FIGURE 3 F–J). First three chaetigers with two aciculae; in chaetigers 4–17 with three aciculae; in chaetigers 18–32 with two aciculae; from chaetiger 33 with only one.

Limbate chaetae of two lengths in same chaetiger: long and short, long blades in dorsal position, short blades in ventral position; limbate chaetae reduced in number around chaetiger 20, and then maintained a similar number until the posterior end. Four types of pectinate chaetae; in anterior chaetigers, thin, isodont narrow, symmetric, with long and slender teeth, 1–2 chaetae, up to 17 teeth ( Fig. 3K View FIGURE 3 ); in median-posterior chaetigers, thin, isodont wide, asymmetric, with short and slender teeth, 15–16 chaetae, up to 26 teeth ( Fig. 3L View FIGURE 3 ); in posterior chaetigers, thick, anodont wide, symmetric, with short and slender teeth, 3–5 chaetae, between 17 and 18 teeth ( Fig. 3M View FIGURE 3 ), and thick, anodont wide, asymmetric, with long and thick teeth, 1–2 chaetae, and up to eight teeth ( Fig. 3N View FIGURE 3 ). Compound spinigers present throughout; with blades of three sizes in anterior chaetigers: shorter and median blades more abundant than longer blades; two lengths blades in median-posterior chaetigers: shorter blades more abundant than longer blades ( Fig. 3O View FIGURE 3 ). Subacicular hooks bidentate, translucent; starting from chaetigers 25L–27R, one per chaetiger, present continuously in all chaetigers, with blunt teeth, distal smaller than proximal, both teeth directed upward. In some chaetigers, unidentate subacicular hook with a hood in distal end ( Fig. 3P View FIGURE 3 ).

Pygidium with dorsal pair of anal cirri as long as the last seven chaetigers, left cirrus lost; ventral pair short, as long as the last chaetiger.

Variation. Material examined with L10 = 3.5–10.4 mm, W10 = 1.2–4.8 mm, TChae = 87–124. Palps reaching the second peristomial ring or first chaetiger; lateral antennae reaching first or second chaetiger; median antenna reaching the middle of first or second chaetiger. The maxillary formula is variable: MII 3–4 + 4, MIII 5–6, MIV 3–4 + 7. The proportions of the maxillary apparatus vary as follows: MI are 2.3–2.8 times longer than the length of maxillary carriers; MI are 4.2–6 times longer than length of closing system; MII are 3–4 times longer than length of cavity opening. Branchiae from chaetigers 15–19 to 13–17 chaetigers before pygidium. Maximum number of branchial filaments varied from two to three and postchaetal lobes were conspicuous in first 18–42 chaetigers. Ventral cirri with a swollen base from chaetiger 6 to 41–51 chaetigers before of pygidium. Start of subacicular hooks in chaetigers 20–27.

Type locality. Trieste and Cres Island, Adriatic Sea .

Distribution. Adriatic Sea, Mediterranean Sea.

Habitat. According to Grube (1864) the material from Lussingrande was possibly collected in the port area, somewhere between 31.1 and 36.6 mm. The substrate type was not recorded.

Etymology. The species is named after Dr. Birger Neuhaus, in recognition of his support and facilities while ICMA carried out the research stay in Berlin, and for allowing the review of this material and other European collections at the Museum für Naturkunder, Berlin.

Remarks. The specimens collected by Grube from the Adriatic Sea and misidentified as Eunice sanguinea (= Marphysa sanguinea ) presented important differences from the neotype of M. sanguinea after a thorough comparison. Herein, the Adriatic Sea material was described as a new species, Marphysa birgeri n. sp..

Marphysa birgeri n. sp. differ from M. sanguinea by the color of subacicular hook, because in former is translucent, whereas in latter species the subacicular hook is reddish on its base, and translucent in distal end. Also, M. birgeri n. sp. (type and additional material, L10 = 3.5–10.4 mm) has branchiae from chaetigers 15–19, the specimens have only two to three branchial filaments, and there are four types of pectinate chaetae present, whereas in M. sanguinea (neotype and additional material, L10 = 11.5–20.4 mm), the branchiae starts in chaetigers 21–25, specimens have from five to six branchial filaments, and there are only three types of pectinate chaetae.

Marphysa birgeri n. sp. resembles M. acicularum ( Bermuda) , M. brasiliensis ( Brazil) , M. bulla (Yellow Sea, China), M. californica (San Diego, California), M. maxidenticulata (Yellow Sea, China), M. parishii ( Brazil) , and M. baileybrockae n. sp. (Hawaii) by having pectinate branchiae with long filaments, the absence of limbate subacicular chaetae, and by the subacicular hook translucent. However, M. birgeri n. sp. has the dorsal cirri digitiform in anterior region, instead of M. acicularum , M. brasiliensis , M. bulla , M. maxidenticulata , M. parishii , and M. baileybrockae n. sp. in which the dorsal cirri are always conical. Moreover, in M. birgeri n. sp. the prechaetal lobe is as transverse fold in anterior chaetigers, whereas in M. baileybrockae n. sp. the prechaetal lobe has the dorsal edge longer than ventral in the first few chaetigers. Furthermore, M. birgeri n. sp. has four types of the pectinate chaetae, in contrast of M. acicularum and M. brasiliensis , that have only three types, and in M. bulla and M. parishii , there are five types of pectinate chaetae. Also, M. birgeri n. sp. has eyes, but in M. maxidenticulata , eyes are absent. Finally, in M. birgeri n. sp. the ventral cirri with swollen base start from chaetiger 6, whereas in M. californica the swollen base start from chaetigers 13–14. The comparison of M. birgeri n. sp. with the related species is provided in Table 1.