Lenticellaria marerubris Simon, Logan & Mottequin

Simon, Eric, Logan, Alan, Zuschin, Martin, Mainguy, Jerome & Mottequin, Bernard, 2016, Lenticellaria and Hillerella, new kraussinoid genera (Kraussinoidea, Brachiopoda) from Indo-Pacific and Red Sea waters: evolution in the subfamily Megerliinae, Zootaxa 4137 (1), pp. 1-34 : 20-22

Lenticellaria marerubris Simon, Logan & Mottequin sp. nov.

Pl. 11, Figs. 1–6.

1921 Megerlia truncata var. paucistriata: Jackson , p. 48.

1973 Megerlia echinata (Fischer & Oehlert) : Cooper, p. 18–19, pl. 3, figs. 27–31). 2008 Megerlia truncata var. paucistriata, Jackson : Bitner, Logan & Gischler, p. 279.

pp 2008 Megerlia truncata: Bitner, Logan & Gischler , pp. 279, 284.

pp v 2008 Megerlia echinata ( Fischer & Oehlert, 1890) : Logan, Tomašových, Zuschin & Grill, p. 395; fig. Q non figs. 2, P, R, S, T.

pp v 2013 Megerlia echinata (Fischer & Oehlert) : Logan & Bitner, pp. 161, 171.

Holotype. Lenticellaria marerubris sp. nov. Pl.11, Figs.1a–1o. Well preserved articulated specimen that has been opened for the present study. It is preserved in the collections of the Natural History Museum of Vienna, Austria ( NHMW 87192/GP 247). The morphological measurements of the holotype are indicated in Table 2 .

Paratypes: NHMW 87192/GP 248: small articulated adult (Pl. 11, Figs.2a–e; Table 2 ) with a dorso-biconvex structure.

NHMW 87192/GP 249: large articulated adult with a quite distorted outline (Pl. 11, Figs. 3a–e; Table 2 ).

NHMW 87192/GP 250: medium sized adult specimen used for illustrating the ventral external ornamentation (Pl. 11, Fig. 4a; Table 2 ).

NHMW 87192/GP 251: early juvenile articulated specimen with a loop at the early cucullate stage of development (Pl. 11, Figs. 5a–f; Table 2 ).

NHMW 87192/GP 252: young articulated specimen showing the two claws of the loop at earliest stage of growth (Pl. 11, Figs. 6a–d).

Etymology. the specific name “ marerubris ” is the latin translation of “from the Red Sea”.

Locus typicus: Dahab, Egypt, Gulf of Aqaba at a depth of 12 m.

Material investigated. Most of the specimens studied were collected by M. Zuschin (Fig. 4) in Dahab, Gulf of Aqaba, Egypt in very shallow water (12 m) and a few specimens more were collected at Port Sudan (see also Logan et al., 2008, fig. 1, p. 300 and Table 1 , p. 301). For this study 38 complete articulated shells, 26 dorsal valves (sometimes fragmented) and 48 ventral valves (sometimes fragmented) were observed.

Diagnosis of species. Micromorphic brachiopod with a very variable outline in dorsal view depending on the topography of the substrate to which the specimen is attached. Shell often distorted but sometimes semicircular in outline. External surface of dorsal valve smooth. Ventral valve with radial tuberculation. Between the radial rows very small scales are regularly developed in concentric lines. Foramen amphithyrid. Cardinal process and hinge plates absent. Inner dorsal valve floor tuberculate. Short crura developed. Loop made of two claws relatively narrow and thin with sharp tip and with a clearly raised pedestal. Descending branches absent. Septum on the ventral valve floor partly interrupted in its posterior portion.

Diagnose de l’espèce. Brachiopode micro-morphique de forme très variable en vue dorsale dépendant de la structure du substrat sur laquelle le spécimen vit fixé. La coquille est souvent fortement déformée mais parfois elle peut apparaître semi-circulaire et plus régulière. La surface externe de la valve dorsale est lisse. La valve ventrale est radialement tuberculée. Entre les rangées de tubercules se développent de très petites écailles disposées concentriquement. Foramen amphithyride. Processus cardinal et plaques de charnières absentes. Surface interne de la valve dorsale tuberculée. Crura très courtes clairement développées. Le brachidium se compose de deux pinces plutôt étroites et minces avec des pointes aigües. Le septum bifide est nettement surélevé. Branches descendantes absentes. Septum de la valve ventrale interrompu dans sa partie postérieure.

Mendiagnosia. « Micromorphic » Brachiopoda dengan bentuk yang sangat bervariasi dilihat atas katup dorsal.Kadang-kadang bentuk juga setengah lingkaran tergantung pada substrat dimana spesimen hidup dilampirkan. Shell sering sangat terdistorsi tapi kadang-kadang bisa muncul berbentuk setengah lingkaran dan lebih teratur. Permukaan luar katup dorsal halus sedangkan permukaan luar katup ventral adalah baris radial dengan tuberkel terucut yang kecil. Antara baris radial dari tuberkel ada banyak skala yang sangat kecil dikembangkan di garis konsentris. Amphithyrid foramen. Proses kardinal dan engsel piring tidak ada. Dalam lantai katup punggung ada tuberkel juga. Krura singkat dikembangkan. Brachidium merupakan dua cakar, sempit dan tipis sederhana dengan teratas tajam. Septum bercabang secara signifikan meningkat. Cabang turun tidak ada. Septum dari katup ventral terputus di bagian posteriornya.

Description. Micromorphic kraussinid brachiopod ( Table 2 ) with a very variable outline in dorsal view depending on the topography of the substrate to which the shell is attached. This species probably lives with its dorsal valve applied tightly to the substrate. The shell is plano-convex or concavo-convex, ventri-biconvex (pl. 11, Fig. 1d), sometimes biconvex and rarely dorso-biconvex (Pl. 11, Fig. 2c–2d). Cardinal area orthocline. Anterior commissure rectimarginate, slightly sulcate to sulcate. Lateral commissure sinuous. Beak erect, often with intact obtuse umbo, sometimes slightly abraded. Amphithyrid foramen shared conspicuously by the dorsal valve. The dorsal side of the foramen is very convex (Pl. 11, Figs. 1g, 2c, 2e). Deltidial plates, very small, triangular, disjunct. Dorsal valve with external surface smooth except for several distinct growth lines. Ventral valve external surface with radial tuberculation and many very small scales disposed concentrically on the surface between the radial rows of tubercles (Pl. 11, Figs. 3b, 4a, 5b, 6b). The tubercles in this species are quite spiny in lateral view (Pl. 11, Figs. 1d–e, 2c).

Obtuse hinge angle quite variable depending of the peculiar outline of each specimen. Cyrtomatodont teeth smooth, robust, short, flat dorsally and obtusely pointed. Pedicle collar thickened, sessile (Pl. 11, Fig. 1n) with numerous punctae parallel to the external surface (visible with a binocular microscope, not with the SEM).

Socket ridges thick, mainly the inner socket ridge that is also higher. The sockets are not deep. Cardinal process absent.

Ventral valve with a low thick septum interrupted in its posterior part. The septum reaches the pedicle collar but does not join it. The commissural dorsal valve floor is heavily tuberculate. The commissural ventral valve floor is not tuberculate but hollow traces of the tips of dorsal tubercles are clearly visible.

The brachidium consists of two pointed relatively slender claws attached to the dorsal valve floor by a relatively high pedestal. The distance between the tips of the claws is highly variable ( Table 2 ) and depends partly on the general size of the specimen but also on the stage of ontogeny reached. Short crura are clearly developed but descending branches are never produced.

Tables

TABLE 2. Lenticellaria marerubris sp. nov. Morphometric measurements were taken from holotype, paratypes and other measurable articulated specimens collected in Dahab (at - 12 m), Gulf of Aqaba, Red Sea by M. Zuschin (NHMW). L: length (mm); LDV: length of dorsal valve; W: width (mm); T: thickness (mm); ØF: maximal width of the foramen (mm); Wbrach: maximum width of the brachidium (mm); ↔: distance between the acute tips of the brachidium (µm); L / W = ratio length to width, T / W = ratio thickness to width; ØF / W: ratio width of foramen to width. Mean values, standard deviations and confidence intervals are indicated.

Specimens L	W	T	Ø F	L/W	T/W	Ø F/W	Wbrach ↔
mm	mm	mm	mm				mm µm
all from Dahab, Gulf of Aqaba 1.95	2.21	0.74	0.66	0.88	0.34	0.30	0.62 170
Holotype NHMW 87192/GP 247 1.34	1.83	0.64	0.47	0.73	0.35	0.26	0.30 75
Paratype NHMW 87192/GP 248 2.10	2.71	0.82	0.72	0.75	0.30	0.27	0.75 262
Paratype NHMW 87192/GP 249 1.99	1.41	0.85	0.70	0.77	0.60	0.50	0.60 3
Paratype NHMW 87192/GP 250 0.99	1.00	0.41	0.30	0.99	0.41	0.30	0.06 0
Paratype NHMW 87192/GP 251 2.81	3.13	1.31	0.94	0.90	0.42	0.30	0.85 230
Paratype NHMW 87192/GP 252
Mean value for all specimens 1.68	2.01	0.58	0.62	0.84	0.47	0.31	0.46 98.55
Number of specimens measured (N) 29	29	29	29	29	29	29	23 20
σ 0.4437	0.4418	0.1621	0.1434	0.1734	0.0730	0.0568	0.1841 77.744
σ/√ N [Confidence interval (±)] 0.0824	0.0820	0.0301	0.0266	0.0322	0.0147	0.0105	0.0384 17.384