Inermonephtys turcica, Kuş & Kurt & Çinar, 2021

Kuş, Sevgi, Kurt, Güley & Çinar, Melih Ertan, 2021, Nephtyidae (Annelida: Polychaeta) from the Sea of Marmara and Black Sea, with descriptions of two new species, Zootaxa 5060 (2), pp. 183-214 : 186-191

publication ID	https://doi.org/ 10.11646/zootaxa.5060.2.2
publication LSID	lsid:zoobank.org:pub:081DB1D0-CD1D-4B53-ADD8-F2831A67A419
DOI	https://doi.org/10.5281/zenodo.5633515
persistent identifier	https://treatment.plazi.org/id/AB5287C1-FFDE-A90E-38B4-AB7BFC38A340
treatment provided by	Plazi
scientific name	Inermonephtys turcica
status	sp. nov.

Treatment

Inermonephtys turcica View in CoL n. sp.

( Figures 2–4 View FIGURE 2 View FIGURE 3 View FIGURE 4 )

urn:lsid:zoobank.org:act:1C719DAD-B8C1-4E95-ACE7-CEC32B55DF07

Material examined. Holotype: ESFM-POL/2000-910 , Aegean Sea, 03 August 2000, Saros Bay , 40˚20’03”N, 26˚13’12”E, 94 m, muddy sand.

Paratypes: ESFM-POL/2013-1305 , Sea of Marmara , 15 June 2013, station Y21, 40°35’14’’N, 27°57’16’’E, 50 m, muddy sand with shell fragments GoogleMaps ; ESFM-POL/2000-911 , Aegean Sea, 03 August 2000, Saros Bay , 40˚20’03”N, 26˚13’12”E, 94 m, muddy sand, 3 specimens ; ESFM-POL/2000-916 , 02 August 2000, Gökçeada , 40˚13’20”N, 26˚03’00”E, 96 m, mud, 2 specimens ; ESFM-POL/2000-912 , 15 September 2000, Didim , 37˚23’55”N, 27˚06’52”E, 71 m, muddy sand, 6 specimens ; ESFM-POL/2000-917 , 14 September 2000, Kuşadası Bay , 37˚55’18”N, 27˚07’41”E, 78 m, mud, 1 specimen ; ESFM-POL/2000-918 , 29 September 2000, Güllük Bay , 37˚12’43”N, 27˚12’18”E, 85 m, mud, 1 specimen ; ESFM-POL/2000-915 , 18 September 2000, Bodrum , 36˚59’00”N, 27˚05’35”E, 83 m, mud, 3 specimens ; ESFM-POL/2000-919 , 18 September 2000, Gökova Bay , 36˚58’30”N, 27˚57’10”E, 109 m, muddy sand, 1 specimen ; ESFM-POL/2000-913 , 21 September 2000, Bozburun , 36˚42’30”N, 28˚00’15”E, 57 m, muddy sand, 1 specimen ; ESFM-POL/2016-349 , 15 August 2016, Aliağa , 38°49’23.88”N, 26°57’4.74”E, 21 m, mud, 1 specimen GoogleMaps ; ESFM-POL/2000-914 , 23 September 2000, Marmaris , 36˚44’30”N, 28˚26’10”E, 110 m, sand with mud, 1 specimen .

Additional material. Levantine Sea: ESFM-POL/2005-3416 , 30 September 2005, Finike Bay , 36°16’3.47”N, 30°11’19.81”E, 100 m, mud, 1 specimen GoogleMaps ; ESFM-POL/2005-3417 , 30 September 2005, Finike Bay , 36°16’7.88”N, 30°12’22.66”E, 100 m, mud, 2 specimens GoogleMaps .

Description. Holotype (ESFM-POL/2000-910) posteriorly incomplete, 25.7 mm long, 2.8 mm wide, with 97 chaetigers; paratypes incomplete (some pygidium-bearing posterior parts present); 25–55 mm long, 2.14–2.9 wide and 44–109 chaetigers. Colour in ethanol yellowish, without any pigmentation ( Fig. 3A View FIGURE 3 ). Prostomium subrectangular (0.6 mm long, 0.5 mm wide), flattened, reaching to chaetiger 2 ( Figs. 2A View FIGURE 2 , 3B View FIGURE 3 ). Anterior margin rounded, posterior margin “V” shaped, with a pair of conspicuous and digitiform nuchal organs ( Figs. 2A View FIGURE 2 , 3B View FIGURE 3 ). Eyes visible in small specimens (1 mm wide) becoming indistinct or absent in larger specimens. Antennae absent. One pair of cushionlike palps with digitiform tips (0.08 mm long) present on ventro-lateral margin of prostomium ( Figs. 2B View FIGURE 2 , 3C View FIGURE 3 ). Pharynx partly everted; proboscis without papillae. One pair of jaws present near pharyngeal base, light brown, spindle-shaped (length about 0.7 mm long, height 0.3 mm) ( Fig. 2C View FIGURE 2 ).

Parapodia of first chaetiger slightly smaller than subsequent ones, directed anteriorly, parallel to prostomium. First parapodia with well developed notopodial postchaetal lamellae, conical neuropodia with protruding acicular lobe, ventral and dorsal cirri. Dorsal and ventral cirri of the first chaetiger conical, with a broad base and tapering distally, similar in size (0.2 mm) ( Figs. 2A View FIGURE 2 , 3B View FIGURE 3 ).

Neuropodial postchaetal lamellae well developed on chaetiger 2 in largest paratype, and on chaetiger 3 or 4 in small specimens. Prechaetal lamellae well developed on neuropodia of chaetiger 4 and on notopodia of chaetiger 5 (in smallest specimens very rudimentary and could not be seen in the whole body). In anterior chaetigers (chaetiger 10), prechaetal lamellae small, broadly rounded, shorter than acicular lobe ( Figs. 2G View FIGURE 2 , 4A View FIGURE 4 1 View FIGURE 1 ); notopodial postchaetal lamellae well developed, broadly rounded, extending well beyond acicular lobe ( Figs. 2G View FIGURE 2 , 4A View FIGURE 4 2 View FIGURE 2 ); neuropodial postchaetal lamellae cylindrical, extending well beyond acicular lobe ( Figs. 2G View FIGURE 2 , 4A View FIGURE 4 2 View FIGURE 2 ). In chaetiger 20, prechaetal and postchaetal lamellae somewhat similar to those on chaetiger 10 ( Figs. 2H View FIGURE 2 , 4B View FIGURE 4 1 View FIGURE 1 ), but notopodial postchaetal lamellae becoming leaf-like with a tapered tip ( Figs. 2H View FIGURE 2 , 4B View FIGURE 4 2 View FIGURE 2 ). In middle chaetigers (chaetiger 40), notopodial postchaetal lamellae narrower distally, tapered towards a rounded tip, neuropodial postchaetal lamellae cylindrical, extending well beyond acicular lobe ( Figs. 2I View FIGURE 2 , 4C View FIGURE 4 2 View FIGURE 2 ); noto- and neuropodial prechaetal lamellae rounded, shorter than acicular lobes ( Figs. 2I View FIGURE 2 , 4C View FIGURE 4 1 View FIGURE 1 ). In posterior chaetigers (chaetiger 102), notopodial postchaetal lamellae leaf-like, similar to chaetiger 20 but with more pointed tips ( Figs. 2J View FIGURE 2 , 4D View FIGURE 4 2 View FIGURE 2 ). Neuropodial postchaetal lamellae reduced, almost not visible ( Figs. 2J View FIGURE 2 , 4D View FIGURE 4 1–2 View FIGURE 1 View FIGURE 2 ). Noto- and neuropodial prechaetal lamellae small, rounded, narrower than anterior and median region ( Figs. 2J View FIGURE 2 , 4D View FIGURE 4 1 View FIGURE 1 ). Acicular lobes oblique-shaped in anterior region ( Figs. 2G View FIGURE 2 , 4A View FIGURE 4 1 –B 1 View FIGURE 1 ), becoming conical in middle region ( Figs. 2I View FIGURE 2 , 4C View FIGURE 4 1 View FIGURE 1 ) and acutely pointed in posterior region ( Figs. 2J View FIGURE 2 , 4D View FIGURE 4 1 View FIGURE 1 ).

Branchiae involute, long and digitiform ( Figs. 2G–J View FIGURE 2 , 4A–D View FIGURE 4 ), heavily ciliated when fully developed, starting from chaetiger 3 (as a small papilla) or 4, in large specimens (body width> 2 mm); from chaetiger 5–7 in medium size specimens (body wide 1 to 2 mm); and from chaetiger 10–13 in small specimens (body wide <1 mm); absent on last 3–4 chaetigers. The smallest complete specimen (length 0.4 mm) completely lacks branchiae.Accessory cirri (basal papillae) conspicuous, first appearing on dorsal surface of branchiae on chaetiger 4–5 (or after second or third chaetiger where branchiae first seen) and disappearing in posterior parapodia, after chaetigers 79–80.

Dorsal cirri conical, longer than branchiae on first 4–5 anterior chaetigers; relatively robust and shorter in following parapodia, becoming slender and longer towards the posterior end ( Figs. 2G–J View FIGURE 2 , 4A–D View FIGURE 4 ). Ventral cirri conical in anterior and middle region, longer than neuropodial acicular lobes ( Figs. 2G–I View FIGURE 2 , 4A–C View FIGURE 4 ), become leaf-like in posterior parapodia, and similar size to the neuropodial lobes ( Figs. 2J View FIGURE 2 , 4D View FIGURE 4 ).

Four types of chaetae present in parapodia; capillary chaetae, barred-like chaetae, spinulated chaetae and lyrate chaetae. Capillary chaetae only present on notopodia of first chaetiger, numbering 3–4. Barred chaetae with very light sandpaper-like appearance ( Figs. 2E View FIGURE 2 , 3F View FIGURE 3 ), thick and long, numbering 7–8 in first chaetiger, becoming thinner and shorter in middle parapodia, first appearing on both preacicular position of noto- and neuropodium of chaetiger 1 and disappearing in chaetiger 30–33. Spinulated chaetae first appearing on postacicular position of neuropodia in chaetiger 1, with one lateral row of coarsely serrated edge ( Figs. 2F View FIGURE 2 , 3D View FIGURE 3 ). Spinulated chaetae begin to appear on both pre- and postacicular position of noto- and neuropodia after disappearence of barred chaetae in chaetiger 30–33, numbering 30–35 in median chaetigers. Lyrate chaetae starting from chaetiger 3 or 4 in adults and on chaetiger 6–7 in small specimens, until the end of body, numbering 1–4 in each ramus, with slightly unequal branches ( Figs. 2D View FIGURE 2 , 3E View FIGURE 3 ).

Aciculae reddish-brown, with strong longitudinal stripes, blunt tips in anterior and middle parapodia, becoming clearly curved in posterior parapodia; numbering 3–4 per ramus in first 7–10 anterior parapodia, 2 between parapodia 10 and 30–33 in adults, and 1 in posterior chaetigers; usually, notopodia carrying one more acicula than neuropodia in anterior chaetigers, and number of aciculae changing according to body size (1 in juveniles, up to 4 in adults).

Pygidium rounded with one anal cirrus placed dorsally.

Reproduction. One of the paratypes had eggs. Eggs appear from median chaetigers to posterior, in the coelomic cavity. The diameter of eggs varied between 100 and 120 μm. Eggs are light yellowish in colour and the specimens did not have any morphological modification on the body.

Remarks. The genus Inermonephtys includes ten valid species: I. aramco Ravara & Carvalho, 2017 , I. brasiliensis Martin, Gil & Da Cunha Lana, 2009, I. foretmontardoi Ravara, Cunha & Pleijel, 2010 , I. gallardi Fauchald, 1968 , I. inermis ( Ehlers, 1887) , I. japonica Imajima & Takeda, 1985 , I. palpata Paxton, 1974 , I. patongi Nateewathana & Hylleberg, 1986 , I. soldius Franco & Rizzo, 2016 and I. tetrophthalmus Rainer & Kaly, 1988 . Inermonephtys turcica n. sp. differs from the other Inermonephtys (except I. foretmontardoi ) species in having long and digitiform neuropodial postchaetal lamellae on the anterior and middle chaetigers. Inermonephtys turcica n. sp. closely resembles I. foretmontardoi and I. inermis . This new species differs from I. inermis in having well developed neuropodial postchaetal lamellae in the anterior and middle regions, which extend well beyond the acicular lobes (rudimentary throughout the body in I. inermis ) and differs from I. foretmontardoi in having barred chaetae in the preacicular area of the noto- and neuropodia, shape of palps (digitiform process with cushion-like base in I. turcica n. sp., ovoid, very small in I. foretmontardoi ) and the first presence of branchiae (from chaetiger 4 in I. foretmontardoi ; from chaetiger 3 to 13 in I. turcica n. sp.). In addition, the neuropodial postchaetal lamellae on the posterior chaetigers are greatly reduced and smaller than acicular lobes in I. turcica n. sp., a character that has not been mentioned in the original description of I. foretmontardoi (holotype incomplete) by Ravara et al. (2010). Another close species, I. aramco from the southern region of the Red Sea, differs from I. turcica n. sp. by the presence of branchiae from chaetiger 15 or 16 (3–13 in I. turcica n. sp.), and the rudimentary neuropodial postchaetal lamellae (well developed in I. turcica n. sp.). In addition, Ravara & Carvalho (2017) described Inermonephtys aff. inermis from the Red Sea based on a single specimen that has mixed characteristics of I. foretmontardoi and I. inermis . This species differs from I. turcica n. sp. by having rounded postchaetal lamellae slightly shorter than the acicular lobe (well developed and longer than acicular lobes in anterior and median chaetigers of I. turcica n. sp.) and spinose preacicular chaetae (preacicular chaetae are barred in anterior and median chaetigers, spinulated in posterior chaetigers in I. turcica n. sp.). The lack of barred chaetae in the posterior chaetigers in I. turcica n. sp. was also mentioned for I. soldius described from the coast of Brazil. However, these two species differ from each other by a set of morphological characters: 1) neuropodial postchaetal lamellae are rounded in I. soldius . vs. long and digitiform in I. turcica n. sp., 2) branchiae start at chaetiger 5 in I. soldius vs. between chaetigers 3 and 13 in I. turcica n. sp., 3) parapodia bear 1 or 2 aciculae in I. soldius vs. bear up to 4 aciculae in anterior parapodia in I. turcica n. sp.

Since the majority of the individuals of Inermonephtys turcica n. sp. were incomplete, except for the smallest specimens, it was not possible to compare biometric features of the species such as the body length, the number of chaetigers and the number of branchiae-bearing chaetigers. However, the width of the chaetiger 15 was used to designate three size groups within I. turcica n. sp.: adult (body width> 2 mm), young (between 2 mm and 1 mm) and juveniles (body width <1 mm). Some characters significantly changed according to the groups. For example, branchiae first appeared on chaetiger 10 or more posteriorly in the juvenile specimens, while they appeared on chaetiger 5–7 in the young specimens and on chaetiger 3 or 4 in the adult specimens. Besides that, the basal papilla on the branchiae was absent in juveniles, while it was very small in the young specimens and very prominent in the adult specimens. The pre- and postchaetal lamellae are rudimentary in the juveniles. A pair of eyes on the prostomium are distinct in the juveniles, whereas they absent or indistinct in the adult specimens.

Distribution. Sea of Marmara, Aegean Sea, Levantine Sea

Habitat. This species was predominantly found in muddy sandy biotopes between 21 and 109 m depths.

Etymology. This species name refers to the type locality, Turkey.