MEDORIPPINAE, Guinot, 2023

Guinot, Danièle, 2023, A new subfamily classification of the highly diversified Dorippidae H. Milne Edwards, 1837 (Crustacea, Decapoda, Brachyura, Dorippoidea), using morphological, molecular and palaeotonlogical data, with special emphasis on its unique female reproductive system, Zoosystema 45 (9), pp. 225-372 : 274-277

Subfamily MEDORIPPINAE n. subfam.

TYPE GENUS. — Medorippe Manning & Holthuis, 1981 (type species by original designation: Cancer lanatus Linnaeus, 1767 ). Other included species:? Medorippe crosnieri Chen, 1988 (see Remarks about the validity of Medorippe crosnieri Chen, 1988 and Fig. 23A, B, D ).

DESCRIPTION

Carapace ( Figs 22A, B ; 23A, B )

Carapace wider than long, hexagonal. Dorsal surface without large tubercles or spines, and only with numerous small tubercles and relatively low ridges. Meso-, meta-, urogastric regions clearly defined. Cardiac region usually with distinct V-or Y-shaped ridge. Precervical groove indistinct; cervical groove more marked but shallow; branchiocardiac groove moderately deep. Gastric pits as two quite distant small slits on depression separating meso-meta gastric regions from urogastric regions. Antero- and posterolateral margins demarcated by distinct but short epibranchial tooth. Front narrow, bidentate, consisting of two very close triangular teeth, separated by narrow emargination. Inner orbital teeth very low, at a much lower level. Superior margin of orbit with fissure. Lower infraorbital margin smooth. Inner suborbital tooth slender, reaching to level of outer orbital tooth. Supraorbital lobe present. Exposure of pleurites 5-7, with smooth texture; margin of carapace lying in small gutter at this level. Carapace posterior rim extending laterally sideways along posterolateral margin, passing behind exposed pleurite 6, and tapering further to reach arthrodial cavity of P2; lined posteriorly by thin strip that is slightly thicker on each lateral side, more concave and elongated in females.

Illustrations: Medorippe lanata: Monod 1933b: 39 , fig. 5A, as Dorippe lanata (reproduced by Monod 1956: fig. 103, erroneously as D. armata ; by Manning & Holthuis 1981: fig. 4a; by Holthuis & Manning 1990: fig. 36; by Sin et al. 2009: fig. 3c); Zariquiey Alvarez 1968: fig. 106d, as D. lanata ; Holthuis & Manning 1990: fig. 37a; Henriksen 2009: fig. 11; Guinot et al. 2013: 219, figs 46A, B, 47A, B; Emmerson 2016: 332.? M. crosnieri Chen, 1988 : fig. 2a (reproduced by Holthuis & Manning 1990: fig. 38a), pl. 1D.

Cephalic structures ( Figs 22 A-C; 23A, B)

Eyestalks elongated but stout and not reaching beyond outer orbital teeth. Antennule not completely folded into fossa. Antenna entirely directed anteriorly: articles 2+3 rather wide, moveable, with external portion elevated; following articles setose; article 4 short, bent inwards; article 5 slightly elongate.

Illustrations: Medorippe lanata: Bouvier 1940: 199 , fig. 140, as Dorippe lanata ; Zariquiey Alvarez 1968: fig. 2f, as D. lanata ; Guinot et al. 2013: figs 42C, 46A, 47A, B.

Oxystomatous disposition ( Figs 4 ; 22C )

Exposed portion of mxp1 endopod protruding beyond extent of mxp3 being very long. Opening of exhalant channels clearly visible in dorsal view between rostral teeth.

Illustrations: Medorippe lanata: Bouvier 1940: 199 , fig. 140, as Dorippe lanata ; Guinot et al. 2013: fig. 42C (reproduced by Davie et al. 2015a: 41, fig. 72-2.14A).

Pereiopods ( Figs 22A, B ; 23A, B )

Left and right chelipeds equal, similar in both sexes and in young adult males; heterochely in large males (from 18 to 29 mm carapace width), with male major chela swollen and setiferous, remaining setiferous even when it becomes larger

Illustrations: Medorippe lanata : A. Milne-Edwards & Bouvier 1900: 33, as Dorippe lanata ; Mori 1986: 81, figs 3, 4; Rossetti et al. 2006: fig. 7.

P2, P3 meri with dorsal margin carrying row of spines ( M. lanata , see Figs22A, B ; 23C ) or unarmed if? M. crosnieri (see Fig. 23A, B, D ) is confirmed as valid. Dactyli narrow and slightly twisted, mostly not fringed with setae. Both P4, P5 reduced and setose; P5 being much thinner and shorter than P4.

Illustrations: Medorippe lanata: Monod 1933b : figs 3C- E, as Dorippe lanata ; Monod 1956: fig. 103, erroneously as D. armata ; Manning & Holthuis 1981: fig. 4a-f; Holthuis & Manning 1990: fig. 36.

Thoracic sternum ( Figs 4 ; 22 C-F)

Thoracic sternum rather wide. Sternites 1 and 2 forming fairly pentagonal, broad shield, separated from sternite 3 by slight lateral notch, extending medially into depressed sulcus; sternite 1 visible dorsally as blunt tip but extending ventrally by large, concealed piece; sternite 3 broad, connected to pterygostome by wide extension; sternite 8 of female without median spine. Sutures 3/4 short but deep, ending in marked boutonniere; sutures 4/5-7/8 interrupted; suture 4/5 straight; suture 5/6 deep, abruptely curved backwards, with conspicuous curve lodging press-button; suture 6/7 oblique; suture 7/8 shorter. Female thoracic sternum extremely tilted backwards at level of ridge crossing whole sternite 6.

Illustrations: Medorippe lanata: Guinot 1979a : fig. 28A, as Dorippe lanata (reproduced by Davie et al. 2015a: fig. 71- 2.18A); Holthuis & Manning 1990: figs 37c; Guinot & Bouchard 1998: figs 15C, D, 16A, B; Guinot et al. 2013: figs 46, 47A, B.

Pleon and telson

Male pleon ( Fig. 22D, F ) with all somites free and dorsal first somites; articular membranes being situated between all somites and on complete breadth of each somite; somite 1 trapezoidal, widening posteriorly, posterior margin concave; somite 2 longer and wider than somite 1; somite 3 widest of all and without teeth in both sexes; pleon regularly narrowing from somite 4 to telson; tip of telson exceeding level of suture 5/6.

Illustrations: Medorippe lanata: Guinot 1979a : fig. 28A, B, as Dorippe lanata ; Guinot & Bouchard 1998: figs 15D, 16B; Guinot et al. 2013: fig. 51G.

Female pleon ( Fig. 22B ) with dorsal first somites, very wide, unarmed, with conspicuous transverse ridges on somites 2-5; telson about as long as wide, suboval, with rounded apex.

Illustrations: Medorippe lanata ( Guinot & Bouchard 1998: fig. 16A).

Pleonal-locking mechanism by press-button ( Figs 4 ; 22 C-E) Press-button located in abruptely curved sternal suture 5/6, effective in both sexes.

Illustrations: Medorippe lanata: Holthuis & Manning 1990 : fig. 37c; Guinot & Bouchard 1998: figs 15C, 16A, B.

Male gonopore and penis

Male gonopore coxal, oriented vertically and unprotected by thoracic sternum, i.e., nearly coxal condition. Penis lying on steep slope formed by sternite 7; sternites 7 and 8 laterally expanded at level of bulb, just leaving gap for penis passage, thus sternites 7 and 8 not joined proximally; bulb and small portion of penial tube (hidden by setae) being the only exposed portions; remaining portion being concealed by pleon.

Illustrations: Medorippe lanata: Guinot 1979a : figs 28, 46F; 1979b: fig. 2A, B1, B2, as Dorippe lanata ; Guinot et al. 2013: fig. 15A.

Gonopods ( Figs 4A ; 22D, E ; 31C )

G1 short, stout, abruptly turned outward, setiferous, with long, very acute, sharp apex, angled at nearly 90°; basal lobe with pappose setae and small denticles.

Illustrations: Medorippe lanata: Brocchi 1875: 102 , fig. 194, as Dorippe lanata ; Monod 1933b: fig. 3F, as D. lanata (reproduced by Manning & Holthuis 1981: fig. 4j; by Sin et al. 2009: fig. 4C; by Davie et al. 2015a: fig. 71-2.31B); Zariquiey Alvarez 1968: fig. 14b, as D. lanata ; Guinot et al. 2013: fig. 15B, D; Vehof 2020: fig. 9.

G2 rather long, straight, with indistinct partition ( Guinot et al. 2013: fig. 15B, C; Vehof 2020: fig. 9A).

Illustrations: Medorippe lanata: Brocchi 1875: 102 , fig. 195, as Dorippe lanata ; Guinot et al. 2013: fig. 15C.

Vulvae ( Figs 4A ; 32C )

Vulva placed anteriorly and medially on sternite 6, recessed at internal margin of very salient sternal prominence in prolongation of sternal ridge; opening small, of oval shape, partially roofed by anterolateral sternal projection; histologically, opening enclosed by protruding parts of vagina. Operculum stiff. Numerous and very small eggs.

Illustrations: Medorippe lanata: Hartnoll 1968: 293 , as Dorippe lanata ; Mori 1986: 78; Holthuis & Manning 1990: 89, fig. 37c, d; Guinot et al. 2013: fig. 42C; Vehof et al. 2017: figs 1B-E, 2B.

Female reproductive system

Studied in Medorippe lanata by Vehof et al. (2017) and Vehof (2020) ( Figs 35C ; 37 ). See below, The female reproductive system in Brachyura , its evolution and unique disposition in Dorippidae .

DISTRIBUTION AND HABITAT

Medorippe lanata inhabits the Eastern Atlantic, from Portugal to Angola ( Crosnier 1970; Muñoz et al. 2012) and South Africa, and the Mediterranean Sea ( Modena et al. 2001; Abelló et al. 2002; Biagi et al. 2002; Pipitone & Arculeo 2003; Zenetos et al. 2005; Fanelli et al. 2007; El Lakhrach et al. 2012), including the Israel Coast ( Galil & Shlagman 2010) and the Adriatic Sea (d’Udekem d’Acoz 1994; Artüz 2007; Çelik et al. 2007; Kocataş & Katağan 2007, Ungaro et al. 2005). It is a neritic species that may be found in rather deep waters to about 100 m, even 112 m in Mauritania ( De Matos-Pita et al. 2017), the depth of 952-1038 m off Morocco given by Türkay (1976: 36) being far in excess ( Manning & Holthuis 1981: 34); preferently on soft sandy bottoms ( Balss 1921: 49; Monod 1956: 92; Manning & Holthuis 1981: 34; Forest & Guinot 1966: 50; d’Udekem d’Acoz 1999: 203; Mori 1986: 78; Rossetti et al. 2006: 21); a wide bathymetrical distribution over muddy bottoms, but with peak abundance on the shelf off the Catalan coast (North-West Mediterranean) ( Abelló et al. 1988: 47, tables 2, 3, 5). In the western Mediterranean, M. lanata is one of the most abundant and frequent brachyurans on the West coast of Central Italy, with a depth range of 15-306 m ( Fanelli et al. 2007).

Medorippe lanata cohabits with Phyllodorippe armata along the West-African coast, in Dahomey (Crosnier coll. et det., MNHN-IU-2009-2004 (= MNHN-B16380), Ghana (in the same station 24, see Forest & Guinot 1966: 36, 50), Gulf of Guinea ( Henriksen 2009), Sierra Leone, and Ivory Coast ( Forest & Guinot 1966: 36, 50; Manning & Holthuis 1981: 36).

CARRYING BEHAVIOUR

Medorippe lanata carries living organisms, but studies on its biology do not mention the carried objects. Marine experiments in Mediterranean aquaria showed that M. lanata preferred large tunicates ( Pesta 1918; Mori 1986; Bedini et al. 2003: figs 2, 7; Rossetti et al. 2006).

REMARKS

Dorippe facchino , originally described by Herbst (1785) while including a reference to the Mediterranean Dorippe lanata of Plancus (1739), is now definitely related to the Indo-West Pacific Dorippoides facchino rather than the Mediterranean Medorippe lanata (see Remarks under Dorippoides facchino ).

As Phyllodorippe armata cohabits with Medorippe lanata in some places, their main distinguishing characteristics, which are also those that separate the two subfamilies Phyllodorippinae n. subfam. and Medorippinae n. subfam., are listed below: in Phyllodorippe , carapace dorsal surface without V-shaped ridge (present on cardiac region in Medorippe ); distinct, sometimes strong epibranchial tooth (variably marked in Medorippe but never as long); no supra-orbital lobe (present in Medorippe ); short exposed portion of mxp1 endopod exceeding extent of mxp3 (long in Medorippe ), thus opening of exhalant channels barely visible in dorsal view (clearly visible in Medorippe ); antennule partially folded, distal part of antennular article out the fossa (unable to be retracted into fossa and directed anteriorly as antenna in Medorippe ); male pleon with low, blunt elevations (more pronounced in Medorippe ); articular membranes between pleonal somites very poorly developed or even absent (present between all pleonal somites in Medorippe , see Guinot et al. 2013: fig. 51G); telson short (longer in Medorippe ); dorsal exposure of a large part of sternite 8 (of a smaller part in Medorippe ); G1 long, very slender, S-shaped, with two short, lobiform distal appendages, and ending in narrow corneous point (short, stout, subdistally abruptly turned outward, setiferous, with long, acute, sharp apex in Medorippe ); vulva submedian and elongate (recessed on external border of salient bulge in Medorippe ); females with erect median spine on sternite 8 (without sternal spine in Medorippe ); suture 6/7 practically continuous medially (interrupted in Medorippe ); marked sexual dimorphism, strong heterochely, with palm of right cheliped strongly swollen and glabrous in males, even in young adults 20 mm width (right chela becoming larger only in large-sized males, about over 30 mm width, but palm never as swollen as in M. lanata ; palm surface setiferous in M. lanata , even when the right chela becomes larger).

The question of the validity of Medorippe crosnieri described from Madagascar and synonymised with Medorippe lanata by Holthuis & Manning (1990: 89, 93, fig. 38) is not resolved (see below).

Figures

FIG. 23. — Medorippinae n. subfam.: A, B,?Medorippe crosnieri Chen, 1988. Mozambique Channel, MAINBAZA Expedition: A, ♂ 21.1 × 25.9 mm, CP 3132, MNHN-IU-2009-1998, with dimorphic chelipeds; B, young ♂ 12.0 × 15.0 mm, CP 3130, MNHN-IU-2009-1999, with symmetrical chelipeds. Photos courtesy of T.-Y.Chan.C, Medorippe lanata (Linnaeus,1767),♂ 23.2 × 28.9 mm,no data,ZRC 2009.0412 (ex MNHN):P2 merus with spinulated dorsal margin;D,?Medorippe crosnieri Chen, 1988, ♂ 21.1 × 25.9 mm, same data as in A (MNHN-IU-2009-1998): P2 merus with smooth dorsal margin.Photographs made by S. Soubzmaigne.

FIG. 22. — Medorippinae n. subfam. Medorippe lanata (Linnaeus, 1767): A, ♂ 18.5 × 23.2 mm, Dahomey Coasts, ZRC 2009.0411: habitus; B, ovigerous ♀ 21.2 × 27.7 mm, Israel, ZRC 1999.0632: habitus; C-E, ♂ 18.5 × 23.2 mm, same data as A: C, anterior ventral view; D, thoracic sternum, press-button and G1; E, G1 and G2. F, ♂ 23.2 × 28.9 mm, no data, ZRC 2009.0412 (ex MNHN): thoracic sternum with pleon.

FIG. 4. — Dorippid thoracic sternum exemplified here by Medorippe lanata (Linnaeus,1767),Mediterranean Sea,dehydrated specimens for skeletal preparation by Sylvie Secretan (MNHN): A, ♂; B, ♀. Abbreviations: b.p., press-button located in curved sternal suture 5/6; cx4, P4 coxa: e, episternite; G1, G2, first and second gonopods; j, sternum/pterygostome junction; m, membrane; m.o., Milne Edwards opening as pterygostomial slit; p, perforation at the end of sternal suture 3/4; r, sternal ridge; s.p., sternal prominence; v, vulva; 1-8, thoracic sternites 1-8; 2/3-7/8, sternal sutures 2/3-7/8. Photographs by Barry van Bakel.

FIG. 31. — Diversity of G1s in the seven dorippid subfamilies (schematic drawings): A, Dorippinae n. stat. (Dorippe quadridens); B, Dorippoidinae n. subfam. (Dorippoides facchino); C, Medorippinae n. subfam.(Medorippe lanata); D-F, Heikeopsinae n.subfam.:D, Heikeopsis?japonica; E, Neodorippe callida; F, Nobilum histrio; G, Paradorippinae n. subfam. (Paradorippe cathayana); H, Philippidorippinae n. subfam. (Philippidorippe philippinensis); I, Phyllodorippinae n. subfam. (Phyllodorippe armata). (A-H, after Holthuis & Manning 1990; I, after Manning & Holthuis 1981). From Sin et al. (2009: fig. 4). Setae not always figured.

FIG. 32. — Diversity of vulvae in the seven dorippid subfamilies (schematic drawings): A, Dorippinae n. stat. (Dorippe quadridens); B, Dorippoidinae n. subfam. (Dorippoides facchino); C, Medorippinae n.subfam.(Medorippe lanata); D-F, Heikeopsinae n. subfam.;D, Heikeopsis?japonica; E, Neodorippe callida; F, Nobilum histrio; G, Paradorippinae n. subfam. (Paradorippe cathayana); H, Philippidorippinae n. subfam. (Philippidorippe philippinensis); I, Phyllodorippinae n. subfam. (Phyllodorippe armata, ♀ 13.0 × 19.0 mm, Guinean Trawling Survey, MNHN-IU-2021-8731 [= MNHN-B24199]). Setae represented only on B. A-H, modified from Holthuis & Manning (1990).

FIG. 35. — Schematic illustrations of female reproductive systems in representatives of four dorippid subfamilies:A, B, Dorippinae n. stat.: A, Dorippe sinica Chen, 1980, as interpreted by Hayer et al. (2016a: fig. 2); B, Dorippe quadridens (Fabricius, 1793) and D. sinica, as interpreted by Vehof et al. (2017: fig. 2A); C, Medorippinae n. subfam.: Medorippe lanata (Linnaeus, 1767), as interpreted by Vehof et al. (2017: fig. 2B); D, Paradorippinae n. subfam.: Paradorippe granulata (De Haan, 1841), as interpreted by Vehof et al. (2018b: fig. 3). E, Heikeopsinae n. subfam.: Heikeopsis japonica (von Siebold, 1824), with the same pattern shared by Neodorippe callida (Fabricius, 1798) and Nobilum histrio (Nobili, 1903), as interpreted by Vehof (2020: fig. 4). Abbreviations: a, apodeme; amb, anteromedian bursa; bu, bursa;cu, cuticle;cv, cuticular valves;bu, bursa; ev, extension of vulva;ge, glandular epithelium; mu, musculature;oc, oocyte; od, oviduct; ov, ovary; plb, posterolateral bursa; sr, seminal receptacle; vg, vagina; v, vulva.

FIG. 37. — Schematic representation of character mapping of sperm storage organs in the different dorippid subfamilies recognised here (except Phyllodorippinae n.subfam.not studied) and in a typical eubrachyuran:ovary with oocytes; oviduct; cuticular bursae (thin black line), of equal or unequal size; seminal receptacle either bilateral twin- or bilateral single,and either completely cuticular (thin black line) or partially glandular (thick black line). The twin system occurs in Dorippinae n. stat., Dorippoidinae n. subfam., Paradorippinae n. subfam. and Philippidorippinae n. subfam.; the single system occurs in Heikeopsinae n. subfam.,Medorippinae n. subfam.and in the typical Eubrachyura (most, see e.g. Ethusidae). Modified from Vehof 2020: figs 20-22).