A new genus and three new species of mangrove slugs from the Indo-West Pacific (Mollusca: Gastropoda: Euthyneura: Onchidiidae) Dayrat, Benoît Goulding, Tricia C. Khalil, Munawar Apte, Deepak Bourke, Adam J. Comendador, Joseph Tan, Shau Hwai European Journal of Taxonomy 2019 2019-02-22 500 1 77 4DRDR Dayrat & Goulding Dayrat & Goulding & Khalil & Apte & Bourke & Comendador & Tan 2019 [424,980,614,641] Gastropoda Onchidiidae Paromoionchis Animalia Systellommatophora 49 50 Mollusca species boholensis gen. et sp. nov.   urn:lsid:zoobank.org:act: 104C35EF-FBF9-4EC2-A5A8-89AC30009270 Figs 31–40    Etymology   Paromoionchis boholensis gen. et sp. nov.is named after Bohol Island, where the typelocality is.    Material examined   Holotype   PHILIPPINES• holotype(28/18 [3288] mm); Bohol, Maribojoc; 09°43.645´N, 123°50.988´E;  15 Jul. 2014; station 193; small island at end of boardwalk, sandy mud and rocks in back of mangrove; PNM0 41266.  Other material   INDONESIA–  Sulawesi•2spec.(35/22[2128]and37/20[2129]mm); Wori; 01°36.055´N, 124°51.730´E;  9 Mar. 2013; station 84; tall mangrove forest of  Sonneratiaand  Avicennia, with old logs; UMIZ0 0 141• 1 spec. (9/6 [2175] mm); Bahoi; 01°43.355´N, 125°01.232´E;  10 Mar. 2013; station 85; sand, small rocks and pieces of wood, near narrow coastal mangrove; UMIZ0 0 142• 1 spec. (20/13 [2199] mm); Tamperong; 01°41.513´N, 125°00.797´E;  12 Mar. 2013; station 87; muddy mangrove with small and dense  Rhizophora; UMIZ0 0 143• 1 spec. (12/8 [2316] mm); Mantehang; 01°41.880´N, 124°46.741´E;  15 Mar. 2013; station 91;  Sonneratiaat low intertidal and  Rhizophoraat high intertidal; UMIZ0 0 144• 1 spec. (20/13 [2360] mm); Panikkiang Island; 04°21.730´S, 119°35.630´E;  25 Mar. 2013; station 94;  Rhizophora,  Avicennia,  Sonneratiaand old logs; UMIZ0 0 145.–   Ambon• 3spec. (40/25 [2849], 45/30 [2850] and 45/25 [2851] mm); Wai; 03°34.652´S, 128°19.526´E;  15 Feb. 2014; station 132; narrow band of old  Avicenniatrees on sandy mud, old logs on ground; UMIZ 0 0 146.–   Seram• 1spec. (45/28 [2884] mm); Piru; 03°04.072´S, 128°11.362´E;  19 Feb. 2014; station 136;   Sonneratiamangrove next to fish market, next to beach of palms and ferns, with cattle roaming around; UMIZ 0 0 147.–   Kei Islands• 2spec. (10/8 [2896] and 17/8 [2901] mm); Un; 05°38.273´S, 132°45.738´E;  23 Feb. 2014; station 137;   Bruguieraand  Rhizophora, some muddy areas and some with coral rubble; UMIZ 0 0 148• 2 spec. (15/10 [2903] and 18/8 [2911] mm); Un; 05°38.273´S, 132°45.738´E;  25 Feb. 2014; station 140; back of mangrove, on rocks, on mud, inside logs and under leaf litter; UMIZ 0 0 149•  3spec. (40/22 [3565], 30/20 [2935] and 40/22 [2937] mm); Fiditan; 05°35.957´S, 132°45.112´E;  28 Feb. 2014; station 144; rocks behind muddy  Rhizophoramangrove; UMIZ 0 0 150. –   Bali• 1 spec. (35/17 [3117] mm); Gilimanuk; 08°10.156´S, 114°26.652´E;  4 Apr. 2014; station 156; muddy mangrove with  Rhizophoraand  Avicenniatrees; UMIZ0 0 140.–   Halmahera• 1 spec. (25/16 [5019] mm); Sofifi; 00°45.473´N, 127°35.897´E;  8 Mar. 2015; station 205;  Sonneratiamangrove, with dense roots and hard mud; UMIZ0 0 151• 2 spec. (47/30 [5140] and 35/22 [5146] mm); Gamkonora; 01°26.911´N, 127°31.625´E;  21 Mar. 2015; station 219; mostly  Rhizophoramangrove with some sandy areas and some open muddy spaces; UMIZ0 0 152.   Fig. 31.  Paromoionchis boholensis  gen. et sp. nov., unit #1, live animals. A. Holotype, dorsal view, 28 mmlong [3288], Philippines, Bohol( PNM 041266).  B. Dorsalview, 26 mmlong [3609], Philippines, Luzon ( PNM 041267).  C. Dorsalview, 38 mmlong [3417], Philippines, Bohol( PNM 041270).  D. Dorsalview, 17 mmlong [3283], Philippines, Bohol( PNM 041268).  E. Dorsalview, 30 mmlong [3372], Philippines, Bohol( PNM 041269).  F. Dorsalview, 17 mmlong [3619], Philippines, Bohol( PNM 041268).  G. Ventralview, same as E. H. Ventralview, 38 mmlong [3422], Philippines, Bohol( PNM 041270).  I. Ventralview, 32 mmlong [3413], Philippines, Bohol( PNM 041270).  J. Ventralview, same as C.   Fig. 32.  Paromoionchis boholensis gen. et sp. nov., unit #2, live animals. A. Dorsal view, 37 mmlong [2129], Indonesia, Sulawesi(UMIZ 00141). B. Dorsal view, 45 mmlong [2851], Indonesia, Ambon(UMIZ 00146). C. Dorsal view, 35 mmlong [3117], Indonesia, Bali(UMIZ 00140). D. Dorsal view, 18 mmlong [2911], Indonesia, Kei (UMIZ 00149). E. Dorsal view, 40 mmlong [2937], Indonesia, Kei (UMIZ 00150). F. Dorsal view, 15 mmlong [2903], Indonesia, Kei (UMIZ 00149). G. Ventral view, 45 mmlong [2884], Indonesia, Seram (UMIZ 00147). H. Ventral view, same as B. I. Ventral view, 45 mmlong [2850], Indonesia, Ambon(UMIZ 00146). J. Frontal view, 17 mmlong [2901], Indonesia, Kei (UMIZ 00148).   PHILIPPINES– Luzon• 1 spec. (25/18 [3609] mm); Lian, Batangas; 13°58.130´N, 120°37.471´E;  5 Jul. 2014; station 179; narrow and impacted mangrove of  Avicennianear village, very sandy, little to no mud; PNM0 41267. –   Bohol• 2 spec. (16/9 [3283] and 17/10 [3619] mm); same data as for holotype; PNM0 41268• 3 spec. (20/15 [3369], 35/18 [3372] and 27/20 [3411] mm); Mabini; 09°51.586´N, 124°34.155´E;  18 Jul. 2014; station 196; open  Avicenniaand  Sonneratiaforest with sand, algae and coral rubble; PNM0 41269• 5 spec. (30/22 [3412], 30/23 [3413], 40/17 [3417], 40/20 [3422] and 42/25 [3423] mm); Maribojoc; 09°44.280´N, 123°49.389´E;  20 Jul. 2014; station 202; uplifted coral rubble with sand and algae, near  Sonneratiatrees; PNM0 41270.   Color and morphology of live animals( Figs 31–32) Live animals are often covered with mud, in which case their dorsal color can hardly be seen. In unit #1, the background of the dorsal notum is brown, occasionally mottled with darker or lighter areas, while in unit #2 it ranges from very light brown (almost white) to dark brown, mottled or not. In some animals, there is a reddish hue on the margin of the dorsal notum (unit #1). In addition, in most animals the tip of the dorsal papillae (with and without dorsal eyes) can be bright yellow. The foot is orange (unit #1) or varies from gray to yellow and orange (unit #2). The hyponotum is also orange, often with a darker ring on the margin which may be bright red (unit #1) or homogenously gray, yellow, or orange, but can also display a mix of two or three of those colors (unit #2). The color of both the foot and the hyponotum of an individual can change very rapidly, especially when disturbed. The ocular tentacles are reddish brown and may or may not be speckled with white dots, like the head. The ocular tentacles are short (just a few millimeters long).   Fig. 33.  Paromoionchis boholensis gen. et sp. nov., unit #1, holotype, Philippines, Bohol[3288] (PNM 041266). A. Digestive system. B. Posterior hermaphroditic (female) reproductive system. C. Male copulatory organs. Abbreviations: ag = accessory penial gland; dd = deferent duct; ddg = dorsal lobe of digestive gland; fgm = female gland mass; hd = hermaphroditic duct; hg = hermaphroditic gland; i = intestine; ms = muscular sac (of accessory penial gland); ov = oviduct; pdg = posterior lobe of digestive gland; ps = penial sheath; r = rectum; rm = retractor muscle; rs = receptaculum seminis; sp = spermatheca; st = stomach; v = vestibule. Scales = 2 mm.  Digestive system( Figs 33A, 34A, 35–36) Radulae measure up to 4.5 mm(unit #1) and 4 mm(unit #2) in length. Examples of radular formulae are presented in Table 4.   Fig. 34.  Paromoionchis boholensis gen. et sp. nov., unit #2, Indonesia, Bali[3117] (UMIZ 00140). A. Digestive system. B. Posterior hermaphroditic (female) reproductive system. C. Male copulatory organs. Abbreviations: ag = accessory penial gland; dd = deferent duct; ddg = dorsal lobe of digestive gland; fgm = female gland mass; hd = hermaphroditic duct; hg = hermaphroditic gland; i = intestine; ms = muscular sac (of accessory penial gland); ov = oviduct; pdg = posterior lobe of digestive gland; ps = penial sheath; r = rectum; rm = retractor muscle; rs = receptaculum seminis; sp = spermatheca; st = stomach; v = vestibule. Scales: A–B = 2 mm; C = 3 mm.   Fig. 35.  Paromoionchis boholensis gen. et sp. nov., unit #1, radula, Philippines, Bohol[3372] (PNM 041269). A. Rachidian and innermost lateral teeth. B. Lateral teeth with rachidian teeth. C. Lateral teeth. D. Outermost lateral teeth. Scales: A = 20 μm; B, D = 30 μm; C = 50 μm.   Fig. 36.  Paromoionchis boholensis gen. et sp. nov., unit #2, radula, Indonesia, Ambon[2851] (UMIZ 00146). A. Rachidian and innermost lateral teeth. B. Lateral teeth with rachidian teeth. C. Lateral teeth. D. Outermost lateral teeth. Scales: A, D = 30 μm; B–C = 50 μm.   Fig. 37.  Paromoionchis boholensis  gen. et sp. nov., unit #1, spine of accessory penial gland. A. Holotype, Philippines, Bohol[3288] ( PNM 041266). B. Philippines, Bohol[3372] ( PNM 041269).  C. Distaltip of spine, same as B. Scales: A–B = 100 μm; C = 10 μm.   Fig. 38.  Paromoionchis boholensis gen. et sp. nov., unit #2, spine of accessory penial gland. A. Indonesia, Bali[3117] (UMIZ 00140). B. Indonesia, Kei [2911] (UMIZ 00149). C. Tip of spine, Indonesia, Ambon[2851] (UMIZ 00146). D. Distal tip of spine, same as B. E. Tip of spine, same as A. F. Tip of spine, Indonesia, Halmahera [5140] (UMIZ 00152). Scales: A–B = 200 μm; C–F = 30 μm.  Reproductive system( Figs 33B–C, 34B–C, 37–38) The male anterior organs consist of the penial complex (penis, penial sheath, vestibule, deferent duct, retractor muscle) and the accessory penial gland (flagellum and hollow spine). The hollow spine of the accessory penial gland is narrow, elongated, slightly curved. Its base is conical. Its diameter is approximately 50 to 70 μm for most of its length and 100–130 μm at its base (unit #1) and approximately 70 to 80 μm for most of its length and 150–200 μm at its base (unit #2). Its length ranges from 1 mm([3288] PNM 0 41266, holotype) to 1.2 mm([3372] PNM 041269) in unit #1 and from 1.1 mm([5019] UMIZ 00151) and 1.3 mm([3117] UMIZ 00140) to 1.8 mm([2911] UMIZ 0 0 149, [5140] UMIZ 00152) in unit #2, and its shape does vary between individuals ( Fig. 38). The penial sheath is narrow and elongated. The retractor muscle is vestigial, i.e., with its distal end being free in the visceral cavity, with no clear insertion (unit #1), or absent or vestigial (unit #2). The deferent duct is highly convoluted, with many loops. Inside the penial sheath, the penis is a narrow, elongated, soft, smooth (no hooks) and hollow tube of approximately 200 μm in diameter.    Distinctive diagnostic features Externally, the color of the foot and hyponotum can help one to identify  Paromoionchis boholensis gen. et sp. nov., but unfortunately it is not fully reliable. Specimens with a bright orange foot and hyponotum are only found in  P. boholensis gen. et sp. nov., especially in unit #1 but also in unit #2; the ventral side of  P. tumidus, which is sympatric with  P. boholensis( Fig. 6), can be orange but not bright orange. However, specimens with a more yellowish or greyish foot and hyponotum cannot be identified externally. The internal anatomy of  P. boholensis gen. et sp. nov.(accessory penial gland, vestigial penial retractor muscle, penis with no hooks) is similar to that of  P. daemelii. However,  P. boholensis gen. et sp. nov.and  P. daemeliido not overlap geographically, at least based on the present data. Thus, within its distribution range  P. boholensis gen. et sp. nov.is the only species with this combination of internal characters. Indeed, the internal characters of the two species of  Paromoionchis gen. nov.with which  P. boholensis gen. et sp. nov.is sympatric (  P. goslineri gen. et sp. nov.and  P. tumidus) are different ( Table 3). It must be noted that the known distribution of species of  Paromoionchis gen. nov.may change as new records are found in the future and so the use of geographic data should only be used with caution for identification.   Distribution( Fig. 6)  Philippines(unit #1): Bohol( typelocality), Luzon. Indonesia(unit #2): Ambon, Bali, Halmahera, Kei Islands, Seram, Sulawesi.   Habitat( Figs 39–40) Unit #1 of  Paromoionchis boholensis gen. et sp. nov.is found on sandy mud or sand with very little mud, in mangroves or near mangrove trees and is rare (it was found at only four stations). Unit #2 is found in open or dense mangroves, on soft or hard mud, as well as on muddy sand and is common (but not as common as  P. tumidusunit #1). 2005634536 2014-07-15 PNM Philippines 9.727417 Maribojoc 1 123.8498 49 50 1 Bohol holotype 2005634530 2013-03-09 UMIZ Indonesia 1.6009166 Wori 1 124.86217 49 50 1 Sulawesi Utara 2005634528 2013-03-10 UMIZ Indonesia 1.7225833 Bahoi 1 125.02053 49 50 1 Sulawesi Utara 2005634521 2013-03-12 UMIZ Indonesia 1.6918833 Tamperong 1 125.01328 49 50 1 Sulawesi Utara 2005634534 2013-03-15 UMIZ Indonesia 1.698 Mantehang 1 124.779015 49 50 1 Sulawesi Utara 2005720719 2013-03-25 UMIZ Indonesia -4.362167 Ambon 1 119.593834 Panikkiang Island 49 50 1 Sulawesi Utara 2005720714 narrow band of old Avicennia trees on sandy mud, old logs on ground 2014-02-15 UMIZ Indonesia -3.5775332 station 132 1 128.32544 Wai 49 50 0 0 146 3 Ambon 2005720716 Sonneratia mangrove next to fish market, next to beach of palms and ferns, with cattle roaming around 2014-02-19 UMIZ Indonesia -3.0678666 station 136 1 128.18936 Piru 49 50 1, 0 0 147 1 Seram 2005720717 Bruguiera and Rhizophora, some muddy areas and some with coral rubble 2014-02-23 UMIZ Indonesia -5.637883 Un 1 132.7623 49 50 0 0 148 2 Kei Islands 2005634543 back of mangrove, on rocks, on mud, inside logs and under leaf litter 2014-02-25 Key Island UMIZ Indonesia -5.637883 Un 1 132.7623 49 50 0 0 149 1 Sulawesi Utara 2005634538 rocks behind muddy Rhizophora mangrove 2014-02-28 UMIZ Indonesia -5.599283 Fiditan 1 132.75186 49 50 0 0 150 3 Sulawesi Utara 2005720722 2014-04-04 UMIZ Indonesia -8.169267 Halmahera 1 114.4442 Gilimanuk 49 50 1 Bali 2005720733 2015-03-08 UMIZ Indonesia 0.7578833 Sofifi 1 127.59828 49 50 1 Bali 2005634525 2015-03-21 UMIZ Indonesia 1.4485166 Gamkonora 1 127.527084 49 50 1 Bali 2005634509 PNM B. Dorsal & C. Dorsal & D. Dorsal & E. Dorsal & F. Dorsal & G. Ventral & E. H. Ventral & I. Ventral & J. Ventral Philippines Bohol 50 51 PNM 041266, PNM 041267, PNM 041270, PNM 041268, PNM 041269 1 Bohol holotype 2005634532 2014-07-05 PNM Philippines 13.968833 Lian 1 120.62452 52 53 1 Batangas 2005634531 2014-07-15 PNM Philippines 9.727417 Maribojoc 1 123.8498 52 53 1 Bohol 2005634544 2014-07-18 PNM Philippines 9.859767 Mabini 1 124.56925 52 53 1 Bohol 2005634541 2014-07-20 PNM Philippines 9.738 Maribojoc 1 123.82315 52 53 1 Bohol 2005634539 PNM C. Distal & B. Scales Philippines Bohol 55 56 PNM 041266, PNM 041269 1 Bohol holotype