taxonID	type	description	language	source
081987A1A21EBB52FF5DDCC7FAE789C7.taxon	diagnosis	Diagnosis. Shell apparently nacreous internally, strongly compressed in anteroposterior direction and laterally expanded; shell compression associated with ca. 30 º rotation of the largest dimension (height) in relation to the anteroposterior axis; lateral outline cardioid; height larger than width; width larger than length. Byssus very well developed (indicating attachment for life); foot vestigial, never leaving infraseptal chamber; posterior byssal retractor muscles wider in cross-section than posterior adductor muscles; anterior labial palps very well developed, cup-shaped; posterior labial palps very reduced, consisting of short projections flush to surrounding surface.	en	Leal, Jos Ẽ H. (2008): A remarkable new genus of carnivorous, sessile bivalves (Mollusca: Anomalodesmata: Poromyidae) with descriptions of two new species. Zootaxa 1764: 1-18, DOI: 10.5281/zenodo.181996
081987A1A21EBB52FF5DDCC7FAE789C7.taxon	description	Description. Shell apparently nacreous internally, thin, equivalve (except for slight anteroposterior overlap at umbo), inequilateral, strongly compressed in anteroposterior direction, lateral outline cardioid, anteroventral surface flat or slightly concave, height larger than width, width larger than length. Umbones projecting dorsally, anterior. Byssal gap anteroventral when present. Hinge with sub-triangular, cardinal-like tooth in each valve; tooth in left valve with cleft distal extremity and more developed than that in right. Ligament external, sunken; inner ligamental layer apparently calcified, white. Outer ligamental layer brown, splitting and diverging anteriorly, with each half curved as a result of tangential component of shell growth; periostracum fused externally with outer ligamental layer. Lithodesma absent. Posterior byssal retractor scar larger than posterior adductor scar, elongate. Lunule absent; escutcheon smooth, well-defined. Animal compressed in anteroventral to posterodorsal direction. Mantle lobes thin, except in siphonal area, with three apertures (see below). Incurrent siphonal length and siphonal opening diameter larger than equivalent dimensions in excurrent siphon. Incurrent siphon eversible, resting inside infraseptal chamber. Incurrent siphonal opening separated from byssal gape by well-developed ventral portion of perisiphonal suture. Base of incurrent siphon surrounded by up to 15 tentacles; tentacles simple, tapered, with one large unpaired tentacle along fused mantle margin dorsal to excurrent siphon; pair of tentacles present internally, in supraseptal chamber, between posterior margin of excurrent siphon and posterior adductor muscle. Septum thin, perforated by byssal opening and by groups of ostia arranged to roughly define three pairs of line segments deployed in septum around byssal opening. Adductor muscles almost parallel to attachment surfaces on valves. Anterior adductor short, flattened; posterior adductor longer, also flattened. Posterior byssal retractors very well developed, attaching to locations close to posterior margin of valves. Anterior byssal retractors thinner, attaching dorsally to internal surface of entrance to umbonal cavity. (I prefer to use byssal retractor muscles instead of pedal retractor muscles.) Byssus well-developed, prominent, circular in cross section. Vestigial foot dorsal to byssus, narrow, or consisting only of an expansion around the middle region of byssus. Position and size of vestigial foot indicates that it can never exit infraseptal chamber. Mouth indicated by beginning of pleats that continue inside esophagus. Posterior labial palps reduced to two small projections flush with surrounding surface and united along midline. Posterior palps not extending posteroventrally on either side of vestigial foot. Anterior labial palps strongly developed, large, folded in the shape of cups over mouth, free from anterior adductor muscle, potentially expandable in posteroventral direction (toward siphonal area). Esophagus very short, with strong internal folds, penetrating stomach anterodorsally. Stomach of Type II, compact, strongly muscular, situated in dorsal orientation in relation to mouth, between two “ horns ” that house digestive diverticula and ovary. Midgut relatively short, connecting to stomach in anterodorsal position, ventral to esophagus. Testes situated in anteroventral position in relation to ovary, ovary overlying the testes. Kidneys situated posterodorsally between remaining of visceral mass and posterior byssal retractor muscle. Kidneys comprising two elongate structures, one on each side of midline of posterior region.	en	Leal, Jos Ẽ H. (2008): A remarkable new genus of carnivorous, sessile bivalves (Mollusca: Anomalodesmata: Poromyidae) with descriptions of two new species. Zootaxa 1764: 1-18, DOI: 10.5281/zenodo.181996
081987A1A21EBB52FF5DDCC7FAE789C7.taxon	materials_examined	Type Species. Dilemma frumarkernorum new species, by original designation.	en	Leal, Jos Ẽ H. (2008): A remarkable new genus of carnivorous, sessile bivalves (Mollusca: Anomalodesmata: Poromyidae) with descriptions of two new species. Zootaxa 1764: 1-18, DOI: 10.5281/zenodo.181996
081987A1A21EBB52FF5DDCC7FAE789C7.taxon	etymology	Etymology. The generic name is the Greek noun dilemma, a proposition consisting of questionable alternatives. It is used in this case to denote the impasses faced by the author in the course of this work.	en	Leal, Jos Ẽ H. (2008): A remarkable new genus of carnivorous, sessile bivalves (Mollusca: Anomalodesmata: Poromyidae) with descriptions of two new species. Zootaxa 1764: 1-18, DOI: 10.5281/zenodo.181996
081987A1A218BB56FF5DDA84FE49891A.taxon	diagnosis	Diagnosis. Shell with sculpture of coarse growth lines; escutcheon not well separated from remainder of shell; foot filiform; byssus relatively thick, robust; siphonal cowl of moderate size; siphonal tentacles arranged around entire incurrent siphonal opening; septal ostia arranged to define three pairs of line segments deployed around byssal opening, roughly delineating a hexagon; siphonal ostia distributed as follows: three anterior, four median, and four posterior.	en	Leal, Jos Ẽ H. (2008): A remarkable new genus of carnivorous, sessile bivalves (Mollusca: Anomalodesmata: Poromyidae) with descriptions of two new species. Zootaxa 1764: 1-18, DOI: 10.5281/zenodo.181996
081987A1A218BB56FF5DDA84FE49891A.taxon	description	Description. SHELL (Figures 1 – 29, 33): Apparently nacreous internally, thin, equivalve (except for slight anteroposterior overlap at umbo), inequilateral, strongly compressed in anteroposterior direction, cardioid in lateral outline. Large byssal gap present in anteroventral position, on central portion of anterior shell surface. Shell sculpture consisting of coarse growth lines, with well-developed carina separating anterior from posterior shell regions. Carina sometimes set by a constriction that resembles a “ pinched ” line parallel to main shell outline. Umbones (Figure 26, U) projecting dorsally, located in anterior position. Umbonal cavity, large, spacious. Hinge with subtriangular, cardinal-like tooth (Figure 26, CT) in each valve, tooth in left valve with cleft distal extremity and more developed than that in right. Corresponding sockets (Figure 26, HS) present in each valve, that in right valve deeper than that in left valve. Posterior lateral tooth elongate, about 1 / 10 shell height, low, present on right valve only (Figures 25, 26, 27, LAT) interlocking with notched depression on left valve (Figure 27, LG). Ligament (Figures 25, 26, 27, LI) external, sunken; inner ligamental layer (Figure 28, IL) in part white, hard, possibly calcified (Figure 28, CIL); outer ligamental layer (Figure 28, OL) brown, with dorsal periostracum adhering to outer layer. Anterior adductor muscle scar (Figures 25, 26, 29, AAS) located on projection close to margin of valve, dorsal to byssal gap. Posterior adductor muscle scar (Figure 25, PAS) about same size as anterior adductor scar. Anterior byssal retractor scar (Figure 26, 29, ABS) small, relatively deep, situated on internal entrance to umbonal cavity. Posterior byssal retractor scar (Figure 25, PBS) larger than posterior adductor scar, elongate. Pallial line (Figures 25, 29, PAL) continuous, strong. Lunule absent. Escutcheon relatively poorly defined, not separated by a prominent groove, but distinguishable from remainder of shell by slightly smoother texture and commarginal band of lighter color. In specimens examined, shell color ranging from dull light-brown to olive-brown, sometimes suffused with peach-orange, usually on posteroventral part of valves. Periostracum light-brown, laid in coarse commarginal lamellae, mostly flaking in live-collected specimens. Macroanatomy. MANTLE MARGIN AND SIPHONS: Mantle margins fused (Figure 31, FM) leaving two siphonal openings (Figures 30, 32, 33, ES, IS) and byssal gape (Figure 31, BGA). Byssal gape circular to elliptical. Siphonal apertures separate; siphonal area sometimes colorful in freshly preserved animals, siphons formed by fusion of inner mantle folds (“ Type A ” of Yonge, 1982). Incurrent siphonal opening (Figures 30, 32, IS) located ventrally, much larger (at least twice as wide) than that of excurrent siphonal opening (Figures 30, 32, 33, ES); siphonal cowl (Figure 32, SC) inverted, resting inside infraseptal chamber, covering incurrent siphonal opening internally, probably eversible for prey capture, relatively short. Base of incurrent siphon surrounded by 15 tentacles (Figures 30 – 32, TN); tentacles simple, tapered. Large unpaired tentacle (Figures 30, 32, UT) present along fused mantle margin dorsal to excurrent siphonal opening; following six (3 + 3) tentacles deployed along membranous hem-like projection of middle mantle fold on each side of intersiphonal junction. Remaining eight tentacles arranged around incurrent siphonal opening. Incurrent siphonal opening located almost ventrally, at least twice as wide as excurrent siphonal opening. Excurrent siphonal opening located posteriorly; angle formed by junction of margins of two valves in posterior direction subtending excurrent siphonal opening (Figures 30, 33). MANTLE CAVITY: Septum (Figure 32, SE) located dorso-ventrally within mantle cavity; septum roughly parallel to anterior shell surface. Septum thin, strong, dividing the mantle cavity into two chambers, the supraseptal (posterior) (Figure 32, SSC) and infraseptal (anterior) (Figure 32, ISC) chambers. Septum attaching to dorsal region of shell posterior to anterior adductor muscles but attaching to ventral region of shell anterior to posterior adductor muscle. Septum perforated by byssal opening (Figure 58 [left], BO) and by groups of ostia arranged to define three pairs of line segments deployed around byssal opening, roughly delineating a hexagon. Ostia distributed as follows: three anterior (Figure 58 [left], ASO), four median (Figure 58 [left], MSO), and four posterior (Figure 58 [left], PSO). MAJOR SHELL MUSCLES: Strong modification of shell shape associated with shape and positioning of adductor muscles: adductor muscles almost parallel to valve surfaces to which they are attached. Anterior adductor muscles (Figures 31, 32, AA) short, flattened; posterior adductor muscles (Figures 30, 32, PA) longer, also flattened. Posterior byssal retractor muscles (Figure 30, 32, PBR) Y-shaped, very well developed, attaching to locations close to posterior margin of valves. Anterior byssal retractor muscles much thinner, attaching dorsally to internal surface of entrance to umbonal cavity. Septal attachment muscles difficult to observe given poor preservation of specimens. BYSSUS AND FOOT: Byssus (Figures 31, 32, BY) well-developed, prominent, circular in cross section, in preserved animals attached to grains of calcareous sediment, consisting of bundle of very fine, fused filaments, cylindrical in cross-section. Byssus originating from a thickened section of vestigial foot (Figure 31, F), which is narrow and filiform. Position and size of vestigial foot indicates that it might never exit infraseptal chamber. MOUTH AND LABIAL PALPS: Mouth ridged internally along entire circumference; posterior labial palps reduced to two vestigial projections flush with surrounding surface. Anterior labial palps very well developed, broad, folded over mouth, potentially expandable in posterodorsal direction. ALIMENTARY SYSTEM: Esophagus with strong folds, very short, opening anterodorsally into stomach. Stomach (Figure 30, ST) of Type II, compact, slightly elongate dorsoventrally, forming posteroventral projection, internally ridged, with ridges stronger in ventral surface. Crystalline style situated just ventral to esophagus opening, projecting slightly into stomach, surrounded by chitinous shield. Openings of digestive diverticula not observed because of poor fixation. Digestive diverticula located in dorsal “ horns ” (Figures 30, DD). Midgut short, connecting to stomach anteroventral position, ventral to esophagus, curving to more posterodorsal position, anus opening in supra-septal chamber near opening of excurrent siphon between posterior byssal retractor muscles. STOMACH CONTENTS: Examination of stomach contents of four paratypes revealed, in one specimen, partially digested remains of unidentifiable ostracod species. KIDNEYS: Kidneys situated posterodorsally between the remainder of visceral mass and posterior byssal retractor muscle. Kidneys comprising two elongate structures, one on each side of the midline of posterior region (Figure 30, K). REPRODUCTIVE SYSTEM: Testes (Figure 31, TE) elongated situated in anteroventral position in relation to ovaries, ovary overlying the testes. Ovaries (Figures 30, OV) consisting of pair of elongated sacs symmetrically deployed on each side of midline. Ovaries and testis ventral to digestive diverticula.	en	Leal, Jos Ẽ H. (2008): A remarkable new genus of carnivorous, sessile bivalves (Mollusca: Anomalodesmata: Poromyidae) with descriptions of two new species. Zootaxa 1764: 1-18, DOI: 10.5281/zenodo.181996
081987A1A218BB56FF5DDA84FE49891A.taxon	materials_examined	Type material. Holotype, BMSM 15029, (length × height × width [in mm] = 7.41 × 20.37 × 16.55) Paratype 1, USNM 1112670 (6.61 × 16.76 × 14.87). Paratype 2, UF 416419 (7.85 × 17.34 × 14.90), Paratype 3, collection of Steve Kern unnumbered (6.79 × 17.24 × 14.52), Paratype 4, collection of Frank Frumar (6 × 16 × 14; not measured with same accuracy as other types), unnumbered. All from type locality, Steve Kern coll. May 2006, dredged, lobster boat. Type locality. Southwest of Key West, Monroe County, Florida, USA, 229 m depth. Abbreviations: AAS = scar of anterior adductor muscle; ABS = scar of anterior byssal retractor muscle; ASC = scar of anterior septal muscle; CIL = calcified part of inner ligament layer; CT = cardinal-like tooth; HS = hinge socket; IL = inner ligament layer; LAT = lateral tooth; LG = lateral groove; LI = ligament; OL = outer ligament layer; PAL = pallial line; PAS = scar of posterior adductor muscle; PBS = scar of posterior byssal retractor muscle; PE = periostracum; OL = outer ligament layer; U = umbo.	en	Leal, Jos Ẽ H. (2008): A remarkable new genus of carnivorous, sessile bivalves (Mollusca: Anomalodesmata: Poromyidae) with descriptions of two new species. Zootaxa 1764: 1-18, DOI: 10.5281/zenodo.181996
081987A1A218BB56FF5DDA84FE49891A.taxon	etymology	Etymology. The new species is named simultaneously after Frank Frumar and Steve Kern, for kindly making the material available for study.	en	Leal, Jos Ẽ H. (2008): A remarkable new genus of carnivorous, sessile bivalves (Mollusca: Anomalodesmata: Poromyidae) with descriptions of two new species. Zootaxa 1764: 1-18, DOI: 10.5281/zenodo.181996
081987A1A218BB56FF5DDA84FE49891A.taxon	discussion	Remarks on habitat and type locality. The depth given above for the type locality is as related by the collector. The two other congeners (below) were collected much deeper, between 805 and 961 m depth. Remarks. See comparative remarks below, under Dilemma spectralis new species and Dilemma inexpectatum new combination.	en	Leal, Jos Ẽ H. (2008): A remarkable new genus of carnivorous, sessile bivalves (Mollusca: Anomalodesmata: Poromyidae) with descriptions of two new species. Zootaxa 1764: 1-18, DOI: 10.5281/zenodo.181996
081987A1A214BB5AFF5DDC6BFF3E8A97.taxon	diagnosis	Diagnosis. Shell thin, with sculpture of shell pores on external shell layer (and corresponding periostracal spicules); foot digitiform (rather than filiform), large (relative to previous species); byssus narrow; siphonal cowl large, and siphonal tentacles more concentrated ventral to the incurrent siphonal opening; arrangement of siphonal ostia with middle and posterior groups of ostia not converging but forming lines roughly parallel with each other; siphonal ostia distributed as follows: five anterior, four median, and six posterior.	en	Leal, Jos Ẽ H. (2008): A remarkable new genus of carnivorous, sessile bivalves (Mollusca: Anomalodesmata: Poromyidae) with descriptions of two new species. Zootaxa 1764: 1-18, DOI: 10.5281/zenodo.181996
081987A1A214BB5AFF5DDC6BFF3E8A97.taxon	description	Description. SHELL (Figures 34 – 40): General shape and proportions as for genus (above). Shell with minute pores on external layer (Figure 39) arranged in lines oblique to shell margin (Figure 39, SM). Shell apparently nacreous internally, very thin, equivalve (except for slight anteroposterior overlap at umbo), inequilateral, strongly compressed in anteroposterior direction; lateral outline cardioid (Figures 34, 35). Moderate byssal gap (Figure 35, BG) in anteroventral position, on central portion of anterior shell surface. Welldeveloped carina separating anterior and posterior shell regions (Figures 36, 44). Umbones, (Figure 37), umbonal cavity, hinge, cardinal-like teeth (Figure 40, CT), hinge sockets, and posterior lateral tooth (present in right valve only) as in previous species. Ligament, inner ligamental layer (Figure 40, IL), outer ligamental layer (Figure 37, OL) as in previous species, with dorsal periostracum adhering to outer layer. Anterior adductor muscle scar, posterior adductor muscle scar anterior byssal retractor scar, and posterior byssal retractor scar as in previous species. Pallial line continuous. Lunule absent. Escutcheon smooth, relatively well-defined, not separated by prominent groove, but distinguishable from remainder of shell by smoother texture and commarginal band of lighter color. Shell color dull-white. Periostracum yellowish-brown, with hollow spicules (Figures 38, 39) along lines oblique to the shell margin; spicules coinciding with minute pores on external shell layer. Macroanatomy. MANTLE MARGIN AND SIPHONS: Mantle margins (Figures 47, 49, FM), and siphonal openings as in previous species. Byssal gape (Figures 35, 49, BGA) circular to elliptical. Siphons separate; siphonal area well-defined; siphons formed by fusion of inner mantle folds (“ Type A ” of Yonge, 1982). Incurrent siphonal opening (Figures 46, 47, 57, IS) and excurrent siphonal opening (Figures 46, 51, 55, 57, ES) as in previous species; siphonal cowl (Figures 47 – 51, 54, SC) as in previous species but considerably larger. Base of the incurrent siphon surrounded by 15 simple, tapered tentacles (Figure 46, TN). Large unpaired tentacle (Figure 46, 57, UT) as in previous species; following four tentacles (2 + 2) (Figure 57, JTN) deployed along each side of intersiphonal junction. Remaining ten tentacles (5 + 5) (Figure 57, ITN) deployed below ventral half of incurrent siphonal opening. Incurrent siphonal opening located almost ventrally, at least twice as wide as excurrent siphonal opening. Relationship between excurrent siphonal opening and angle formed by junction of margins of two valves in posterior direction as in previous species. Pair of tentacles present internally (Figures 51, 55, IT), in supraseptal chamber, between posterior margin of excurrent siphon and posterior adductor muscle. MANTLE CAVITY: Septum (Figures 50, 51, 54, SE), supraseptal (posterior) chamber (Figure 48, 55, SSC), and infraseptal (anterior) chamber (Figures 48, 54, ISC) as in previous species. Septum attachment to internal shell surface as in previous species. Septum perforated by byssal opening (Figure 58 [right], BO) and by groups of ostia arranged to define three pairs of line segments deployed around byssal gape. Segments containing posterior (Figures 47, 49, 52, 58 [right], PSO) and middle (Figures 49, 52, 58 [right], MSO) groups of ostia roughly parallel to one another, each forming ca. 45 º angle with sagittal plane; segment defined by anterior group of ostia (Figures 46, 52, 58 [right], ASO) forming ca. 135 º angle with sagittal plane. Ostia distributed as follows: five anterior, four median, and six posterior. MAJOR SHELL MUSCLES: Relationship between strongly modified shell shape and positioning of adductor muscles as in previous species. Anterior adductor muscles (Figures 47 – 50, 54, AA), posterior adductor muscles (Figures 46, 48, 50, 51, 54, 55, 57, PA), posterior byssal retractor muscles (Figures 46, 48, 50, 51, 54, 55, 57, PBR), anterior byssal retractor muscles as in previous species. Anterior and lateral septal muscle insertions difficult to observe due to poor specimen preservation. Posterior septal muscle insertions Figure 46, PSM) located adjacent to insertion of posterior adductor muscles. BYSSUS AND FOOT: Byssus (Figures 47 – 50, 54, BY) well developed, elliptical in cross section; byssus of holotype attached to sliver of dense, apparently volcanic, rock. Byssus consisting of consisting of bundle of very fine, fused filaments, originating from collar-like expansion of vestigial foot (Figures 47, 49, 50, 53, F), the latter narrow, digitiform. As in previous species, position and size of vestigial foot indicates that it might never exit infraseptal chamber. MOUTH AND LABIAL PALPS: Mouth (Figures 53, 54, 56, MO) as in previous species; posterior labial palps (Figure 53, 56, PLP) reduced to two vestigial projections flush with surrounding surface. Anterior labial palps (Figure 47, 48, 53, 54, 56, ALP) very well developed, strongly ridged, pointed distally, potentially expandable in posterodorsal direction. ALIMENTARY SYSTEM: Esophagus (Figure 54, OE) and stomach (Figures 46, 54, ST) generally as in previous species, but stomach more globose. Openings of digestive diverticula situated anteriorly, between esophagus and midgut opening in stomach. Digestive diverticula located in dorsal “ horns ” (Figures 46, 48, 54, DD.) Midgut (Figure 54, MG) and anus as in previous species. STOMACH CONTENTS: Examination of stomach contents of holotype revealed single specimen, still relatively intact, of possibly unnamed cirolanid isopod (Marilyn Schotte, pers. comm., November 1, 2007); the stomach was greatly distended (Figure 57). Ms. Schotte could not find any evidence of eyes, ommatidia, or pigment, which indicates that the prey item was an eyeless isopod. KIDNEYS: Kidneys situated posterodorsally between the remainder of visceral mass and posterior byssal retractor muscle. Kidneys comprising two elongate structures, one on each side of midline of posterior region. Proximal regions of kidney elongate, with distal regions broader, club-shaped (Figures 46 – 48, 54, 57, K). REPRODUCTIVE SYSTEM: Testes (Figures 46, 48, TE) elongated situated in anteroventral position in relation to ovaries, ovary overlying the testes. Ovaries (Figures 46, 48, 54, OV) consisting of pair of elongated sacs symmetrically deployed on each side of midline. Ovaries and testes ventral to digestive diverticula.	en	Leal, Jos Ẽ H. (2008): A remarkable new genus of carnivorous, sessile bivalves (Mollusca: Anomalodesmata: Poromyidae) with descriptions of two new species. Zootaxa 1764: 1-18, DOI: 10.5281/zenodo.181996
081987A1A214BB5AFF5DDC6BFF3E8A97.taxon	materials_examined	Type Material. Holotype, MNHN 20818 (length × height × width [in mm] = 5.20 × 13.50 × 11.77), N / O ALIS, Campagne MUSORSTOM 8, station CP- 1112 (beam trawl), P. Bouchet and B. Richer de Forges coll., 0 8 Oct. 1994, from type locality. Type Locality. Off Republic of Vanuatu, 14 ° 53 ' S, 167 ° 12 ' E, 950 – 961 m, bottom with boulders.	en	Leal, Jos Ẽ H. (2008): A remarkable new genus of carnivorous, sessile bivalves (Mollusca: Anomalodesmata: Poromyidae) with descriptions of two new species. Zootaxa 1764: 1-18, DOI: 10.5281/zenodo.181996
081987A1A214BB5AFF5DDC6BFF3E8A97.taxon	etymology	Etymology. From the Latin spectrum, meaning apparition or an evanescent, supernatural image.	en	Leal, Jos Ẽ H. (2008): A remarkable new genus of carnivorous, sessile bivalves (Mollusca: Anomalodesmata: Poromyidae) with descriptions of two new species. Zootaxa 1764: 1-18, DOI: 10.5281/zenodo.181996
081987A1A214BB5AFF5DDC6BFF3E8A97.taxon	discussion	Remarks. Dilemma spectralis differs from D. frumarkernorum in having a thinner shell, shell pores (and corresponding periostracal spicules), a filiform (rather than digitiform) foot, a different arrangement of septal ostia, a larger siphonal cowl, and siphonal tentacles more concentrated ventral to the incurrent siphonal opening.	en	Leal, Jos Ẽ H. (2008): A remarkable new genus of carnivorous, sessile bivalves (Mollusca: Anomalodesmata: Poromyidae) with descriptions of two new species. Zootaxa 1764: 1-18, DOI: 10.5281/zenodo.181996
081987A1A217BB5FFF5DDF0CFD808D5C.taxon	diagnosis	Diagnosis. Shell with sculpture of strong, regular commarginal grooves on posterior surface, with interspaces twice as wide. Byssal gap absent. Escutcheon relatively large, smooth, well-defined, separated by prominent groove from remainder of posterior shell surface.	en	Leal, Jos Ẽ H. (2008): A remarkable new genus of carnivorous, sessile bivalves (Mollusca: Anomalodesmata: Poromyidae) with descriptions of two new species. Zootaxa 1764: 1-18, DOI: 10.5281/zenodo.181996
081987A1A217BB5FFF5DDF0CFD808D5C.taxon	description	Description (based on holotype, a left shell valve). SHELL (Figures 41 – 45): Sculpture of strong, regular commarginal grooves on posterior surface, with interspaces at least twice as wide. Anterior shell surface smoother, with worn aspect and commarginal growth lines that often coincide with grooves on posterior surface. Shell apparently nacreous internally, relatively thick, compressed in anteroposterior direction, cardioid in lateral outline (assuming that right valve is symmetrical with left). Byssal gap absent. Well-developed carina separating anterior from posterior shell surfaces. Umbones and umbonal cavity as in previous species. Umbones, umbonal cavity, hinge, cardinal-like teeth (Figures 40, 45, CT), hinge sockets (Figure 45, HS), as in previous species. Posterior lateral tooth (present in right valve only) not seen. Ligament lacking in examined holotype. Anterior adductor muscle scars (Figure 45, AAS), posterior adductor muscle scars as in previous species. Anterior and posterior byssal retractor scars difficult to examine due to worn nature of holotype. Pallial line continuous. Lunule absent. Escutcheon (Figure 41, ES) relatively large, smooth, well-defined, separated by prominent groove from remainder of posterior shell surface. Periostracum lacking in holotype. Shell color dirty-white with some staining evocative of iron oxide.	en	Leal, Jos Ẽ H. (2008): A remarkable new genus of carnivorous, sessile bivalves (Mollusca: Anomalodesmata: Poromyidae) with descriptions of two new species. Zootaxa 1764: 1-18, DOI: 10.5281/zenodo.181996
081987A1A217BB5FFF5DDF0CFD808D5C.taxon	materials_examined	Type Material. Holotype, NMNZ M. 018488, 3.94 mm (length) × 8.19 mm (height) × 8.16 mm (width; width was calculated by multiplying width of single left valve by two, assuming the shell to be perfectly equivalve), RNZFA TUI, 15 July 1962 (Images available online at Museum of New Zealand Te Papa Tongarewa, 2007.) Paratype, one right valve NMNZ M 18491 (not seen; both assumed from type locality). Type Locality. North of Three Kings Islands, 34 º 00 ' S, 171 º 55 ' E, 805 m depth, bryozoan and shell bottom.	en	Leal, Jos Ẽ H. (2008): A remarkable new genus of carnivorous, sessile bivalves (Mollusca: Anomalodesmata: Poromyidae) with descriptions of two new species. Zootaxa 1764: 1-18, DOI: 10.5281/zenodo.181996
081987A1A217BB5FFF5DDF0CFD808D5C.taxon	discussion	Remarks. This species is also known only from its type locality. It was originally described as a Corculum (Cardiidae) from the holotype, a left valve (above), and one paratype, a right valve (not examined). The original description gave dimensions as “ 2.7 mm (length) × 8.0 mm (height). ” Notwithstanding the lack of known soft parts, Dilemma inexpectatum is easily separated from the two new species described above by its sculpture of strong grooves on its posterior surface that contrasts with a relatively large and very well-defined escutcheon devoid of sculpture, a relatively thicker shell, and the lack of a byssal gap on the anterior shell surface.	en	Leal, Jos Ẽ H. (2008): A remarkable new genus of carnivorous, sessile bivalves (Mollusca: Anomalodesmata: Poromyidae) with descriptions of two new species. Zootaxa 1764: 1-18, DOI: 10.5281/zenodo.181996
